From patchwork Wed Nov 7 19:48:36 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672991 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E1F9E13AD for ; Wed, 7 Nov 2018 19:52:21 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D56DE2CFB1 for ; Wed, 7 Nov 2018 19:52:21 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D3B5D2D047; Wed, 7 Nov 2018 19:52:21 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6F4E22CFB1 for ; Wed, 7 Nov 2018 19:52:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726788AbeKHFVC (ORCPT ); Thu, 8 Nov 2018 00:21:02 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41830 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726337AbeKHFVC (ORCPT ); Thu, 8 Nov 2018 00:21:02 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTp4-00070Q-OG; Wed, 07 Nov 2018 20:49:07 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 01/23] x86/fpu: Use ULL for shift in xfeature_uncompacted_offset() Date: Wed, 7 Nov 2018 20:48:36 +0100 Message-Id: <20181107194858.9380-2-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The xfeature mask is 64bit so a shift from a number to its mask should have LL prefix or else nr > 31 will be lost. This is not a problem now but should XFEATURE_MASK_SUPERVISOR gain a bit >31 then this check won't catch it. Add a ULL suffix so >31bit number will be properly shifted. Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/kernel/fpu/xstate.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 87a57b7642d36..9dc0a2c8c2755 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -444,7 +444,7 @@ static int xfeature_uncompacted_offset(int xfeature_nr) * format. Checking a supervisor state's uncompacted offset is * an error. */ - if (XFEATURE_MASK_SUPERVISOR & (1 << xfeature_nr)) { + if (XFEATURE_MASK_SUPERVISOR & (1ULL << xfeature_nr)) { WARN_ONCE(1, "No fixed offset for xstate %d\n", xfeature_nr); return -1; } From patchwork Wed Nov 7 19:48:37 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672981 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8583817D4 for ; Wed, 7 Nov 2018 19:51:32 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 77BAD2CFB7 for ; Wed, 7 Nov 2018 19:51:32 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6BE382D014; Wed, 7 Nov 2018 19:51:32 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DB3582CFB7 for ; Wed, 7 Nov 2018 19:51:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727197AbeKHFVH (ORCPT ); Thu, 8 Nov 2018 00:21:07 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41874 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725953AbeKHFVH (ORCPT ); Thu, 8 Nov 2018 00:21:07 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTp5-00070Q-J5; Wed, 07 Nov 2018 20:49:07 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 02/23] x86/fpu: Remove fpu->initialized usage in __fpu__restore_sig() Date: Wed, 7 Nov 2018 20:48:37 +0100 Message-Id: <20181107194858.9380-3-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This is a preparation for the removal of the ->initialized member in the fpu struct. __fpu__restore_sig() is deactivating the FPU via fpu__drop() and then setting manually ->initialized followed by fpu__restore(). The result is that it is possible to manipulate fpu->state and the state of registers won't be saved/restore on a context switch which would overwrite state. Don't access the fpu->state while the content is read from user space and examined / sanitized. Use a temporary buffer kmalloc() buffer for the preparation of the FPU registers and once the state is considered okay, load it. Should something go wrong, return with and error and without altering the original FPU registers. The removal of "fpu__initialize()" is a nop because fpu->initialized is already set for the user task. Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/include/asm/fpu/signal.h | 2 +- arch/x86/kernel/fpu/regset.c | 5 ++-- arch/x86/kernel/fpu/signal.c | 41 ++++++++++++------------------- 3 files changed, 19 insertions(+), 29 deletions(-) diff --git a/arch/x86/include/asm/fpu/signal.h b/arch/x86/include/asm/fpu/signal.h index 44bbc39a57b30..7fb516b6893a8 100644 --- a/arch/x86/include/asm/fpu/signal.h +++ b/arch/x86/include/asm/fpu/signal.h @@ -22,7 +22,7 @@ int ia32_setup_frame(int sig, struct ksignal *ksig, extern void convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk); -extern void convert_to_fxsr(struct task_struct *tsk, +extern void convert_to_fxsr(struct fxregs_state *fxsave, const struct user_i387_ia32_struct *env); unsigned long diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c index bc02f5144b958..5dbc099178a88 100644 --- a/arch/x86/kernel/fpu/regset.c +++ b/arch/x86/kernel/fpu/regset.c @@ -269,11 +269,10 @@ convert_from_fxsr(struct user_i387_ia32_struct *env, struct task_struct *tsk) memcpy(&to[i], &from[i], sizeof(to[0])); } -void convert_to_fxsr(struct task_struct *tsk, +void convert_to_fxsr(struct fxregs_state *fxsave, const struct user_i387_ia32_struct *env) { - struct fxregs_state *fxsave = &tsk->thread.fpu.state.fxsave; struct _fpreg *from = (struct _fpreg *) &env->st_space[0]; struct _fpxreg *to = (struct _fpxreg *) &fxsave->st_space[0]; int i; @@ -350,7 +349,7 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset, ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &env, 0, -1); if (!ret) - convert_to_fxsr(target, &env); + convert_to_fxsr(&target->thread.fpu.state.fxsave, &env); /* * update the header bit in the xsave header, indicating the diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 61a949d84dfa5..5777ee0c32fed 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -207,11 +207,11 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size) } static inline void -sanitize_restored_xstate(struct task_struct *tsk, +sanitize_restored_xstate(union fpregs_state *state, struct user_i387_ia32_struct *ia32_env, u64 xfeatures, int fx_only) { - struct xregs_state *xsave = &tsk->thread.fpu.state.xsave; + struct xregs_state *xsave = &state->xsave; struct xstate_header *header = &xsave->header; if (use_xsave()) { @@ -238,7 +238,7 @@ sanitize_restored_xstate(struct task_struct *tsk, */ xsave->i387.mxcsr &= mxcsr_feature_mask; - convert_to_fxsr(tsk, ia32_env); + convert_to_fxsr(&state->fxsave, ia32_env); } } @@ -284,8 +284,6 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) if (!access_ok(VERIFY_READ, buf, size)) return -EACCES; - fpu__initialize(fpu); - if (!static_cpu_has(X86_FEATURE_FPU)) return fpregs_soft_set(current, NULL, 0, sizeof(struct user_i387_ia32_struct), @@ -314,41 +312,34 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) * thread's fpu state, reconstruct fxstate from the fsave * header. Validate and sanitize the copied state. */ + union fpregs_state *state; + void *tmp; struct user_i387_ia32_struct env; int err = 0; - /* - * Drop the current fpu which clears fpu->initialized. This ensures - * that any context-switch during the copy of the new state, - * avoids the intermediate state from getting restored/saved. - * Thus avoiding the new restored state from getting corrupted. - * We will be ready to restore/save the state only after - * fpu->initialized is again set. - */ - fpu__drop(fpu); + tmp = kmalloc(sizeof(*state) + fpu_kernel_xstate_size + 64, GFP_KERNEL); + if (!tmp) + return -ENOMEM; + state = PTR_ALIGN(tmp, 64); if (using_compacted_format()) { - err = copy_user_to_xstate(&fpu->state.xsave, buf_fx); + err = copy_user_to_xstate(&state->xsave, buf_fx); } else { - err = __copy_from_user(&fpu->state.xsave, buf_fx, state_size); + err = __copy_from_user(&state->xsave, buf_fx, state_size); if (!err && state_size > offsetof(struct xregs_state, header)) - err = validate_xstate_header(&fpu->state.xsave.header); + err = validate_xstate_header(&state->xsave.header); } if (err || __copy_from_user(&env, buf, sizeof(env))) { - fpstate_init(&fpu->state); - trace_x86_fpu_init_state(fpu); err = -1; } else { - sanitize_restored_xstate(tsk, &env, xfeatures, fx_only); + sanitize_restored_xstate(state, &env, + xfeatures, fx_only); + copy_kernel_to_fpregs(state); } - fpu->initialized = 1; - preempt_disable(); - fpu__restore(fpu); - preempt_enable(); - + kfree(tmp); return err; } else { /* From patchwork Wed Nov 7 19:48:38 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672987 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 58C1E15A6 for ; Wed, 7 Nov 2018 19:51:54 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4B9502D027 for ; Wed, 7 Nov 2018 19:51:54 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 496862D037; Wed, 7 Nov 2018 19:51:54 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A4B742D04B for ; Wed, 7 Nov 2018 19:51:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727027AbeKHFVD (ORCPT ); Thu, 8 Nov 2018 00:21:03 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41831 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726435AbeKHFVC (ORCPT ); Thu, 8 Nov 2018 00:21:02 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTp6-00070Q-3X; Wed, 07 Nov 2018 20:49:08 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 03/23] x86/fpu: Remove fpu__restore() Date: Wed, 7 Nov 2018 20:48:38 +0100 Message-Id: <20181107194858.9380-4-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP There are no users of fpu__restore() so it is time to remove it. The comment regarding fpu__restore() and TS bit is stale since commit b3b0870ef3ffe ("i387: do not preload FPU state at task switch time") and has no meaning since. Signed-off-by: Sebastian Andrzej Siewior --- Documentation/preempt-locking.txt | 1 - arch/x86/include/asm/fpu/internal.h | 1 - arch/x86/kernel/fpu/core.c | 24 ------------------------ arch/x86/kernel/process_32.c | 4 +--- arch/x86/kernel/process_64.c | 4 +--- 5 files changed, 2 insertions(+), 32 deletions(-) diff --git a/Documentation/preempt-locking.txt b/Documentation/preempt-locking.txt index 509f5a422d571..dce336134e54a 100644 --- a/Documentation/preempt-locking.txt +++ b/Documentation/preempt-locking.txt @@ -52,7 +52,6 @@ preemption must be disabled around such regions. Note, some FPU functions are already explicitly preempt safe. For example, kernel_fpu_begin and kernel_fpu_end will disable and enable preemption. -However, fpu__restore() must be called with preemption disabled. RULE #3: Lock acquire and release must be performed by same task diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 5f7290e6e954e..32ea458f13b5c 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -28,7 +28,6 @@ extern void fpu__initialize(struct fpu *fpu); extern void fpu__prepare_read(struct fpu *fpu); extern void fpu__prepare_write(struct fpu *fpu); extern void fpu__save(struct fpu *fpu); -extern void fpu__restore(struct fpu *fpu); extern int fpu__restore_sig(void __user *buf, int ia32_frame); extern void fpu__drop(struct fpu *fpu); extern int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu); diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 2ea85b32421a0..9387e0fec7d17 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -305,30 +305,6 @@ void fpu__prepare_write(struct fpu *fpu) } } -/* - * 'fpu__restore()' is called to copy FPU registers from - * the FPU fpstate to the live hw registers and to activate - * access to the hardware registers, so that FPU instructions - * can be used afterwards. - * - * Must be called with kernel preemption disabled (for example - * with local interrupts disabled, as it is in the case of - * do_device_not_available()). - */ -void fpu__restore(struct fpu *fpu) -{ - fpu__initialize(fpu); - - /* Avoid __kernel_fpu_begin() right after fpregs_activate() */ - kernel_fpu_disable(); - trace_x86_fpu_before_restore(fpu); - fpregs_activate(fpu); - copy_kernel_to_fpregs(&fpu->state); - trace_x86_fpu_after_restore(fpu); - kernel_fpu_enable(); -} -EXPORT_SYMBOL_GPL(fpu__restore); - /* * Drops current FPU state: deactivates the fpregs and * the fpstate. NOTE: it still leaves previous contents diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index 5046a3c9dec2f..d9510452b69a6 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -274,9 +274,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) /* * Leave lazy mode, flushing any hypercalls made here. * This must be done before restoring TLS segments so - * the GDT and LDT are properly updated, and must be - * done before fpu__restore(), so the TS bit is up - * to date. + * the GDT and LDT are properly updated. */ arch_end_context_switch(next_p); diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 0e0b4288a4b2b..cf2c157714594 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -576,9 +576,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) /* * Leave lazy mode, flushing any hypercalls made here. This * must be done after loading TLS entries in the GDT but before - * loading segments that might reference them, and and it must - * be done before fpu__restore(), so the TS bit is up to - * date. + * loading segments that might reference them. */ arch_end_context_switch(next_p); From patchwork Wed Nov 7 19:48:39 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672989 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7AC6815A6 for ; Wed, 7 Nov 2018 19:52:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6D1212CF99 for ; Wed, 7 Nov 2018 19:52:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 6B8D62D04F; Wed, 7 Nov 2018 19:52:00 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 199362D04A for ; Wed, 7 Nov 2018 19:52:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726880AbeKHFXp (ORCPT ); Thu, 8 Nov 2018 00:23:45 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41836 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726495AbeKHFVC (ORCPT ); Thu, 8 Nov 2018 00:21:02 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTp6-00070Q-UB; Wed, 07 Nov 2018 20:49:09 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 04/23] x86/entry/32: Remove asm/math_emu.h include Date: Wed, 7 Nov 2018 20:48:39 +0100 Message-Id: <20181107194858.9380-5-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The math_emu.h header files contains the definition of struct math_emu_info. It is not used in this file. Remove asm/math_emu.h include. Signed-off-by: Sebastian Andrzej Siewior Reviewed-by: Andy Lutomirski --- arch/x86/kernel/process_32.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index d9510452b69a6..b8a935adc96fc 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -44,9 +44,6 @@ #include #include #include -#ifdef CONFIG_MATH_EMULATION -#include -#endif #include From patchwork Wed Nov 7 19:48:40 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672947 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 05F4213AD for ; Wed, 7 Nov 2018 19:49:17 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EC6182C888 for ; Wed, 7 Nov 2018 19:49:16 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DFDE52CF64; Wed, 7 Nov 2018 19:49:16 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 36CBF2CA32 for ; Wed, 7 Nov 2018 19:49:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727074AbeKHFVD (ORCPT ); Thu, 8 Nov 2018 00:21:03 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41841 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725953AbeKHFVD (ORCPT ); Thu, 8 Nov 2018 00:21:03 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTp7-00070Q-NO; Wed, 07 Nov 2018 20:49:09 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 05/23] x86/fpu: Remove preempt_disable() in fpu__clear() Date: Wed, 7 Nov 2018 20:48:40 +0100 Message-Id: <20181107194858.9380-6-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The preempt_disable() section was introduced in commit a10b6a16cdad8 ("x86/fpu: Make the fpu state change in fpu__clear() scheduler-atomic") and it was said to be temporary. fpu__initialize() initializes the FPU struct to its "init" value and then sets ->initialized to 1. The last part is the important one. The content of the `state' does not matter because it gets set via copy_init_fpstate_to_fpregs(). A preemption here has little meaning because the register will always be set to the same content after copy_init_fpstate_to_fpregs(). A softirq with a kernel_fpu_begin() could also force to save FPU's register after fpu__initialize() without changing the outcome here. Remove the preempt_disable() section in fpu__clear(), preemption here does not hurt. Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/kernel/fpu/core.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 9387e0fec7d17..b7d9b19ab8116 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -368,11 +368,9 @@ void fpu__clear(struct fpu *fpu) * Make sure fpstate is cleared and initialized. */ if (static_cpu_has(X86_FEATURE_FPU)) { - preempt_disable(); fpu__initialize(fpu); user_fpu_begin(); copy_init_fpstate_to_fpregs(); - preempt_enable(); } } From patchwork Wed Nov 7 19:48:41 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672985 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8E59613AD for ; Wed, 7 Nov 2018 19:51:46 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 827AB2D02F for ; Wed, 7 Nov 2018 19:51:46 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 765472CFEC; Wed, 7 Nov 2018 19:51:46 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 501292CFCC for ; Wed, 7 Nov 2018 19:51:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727188AbeKHFVF (ORCPT ); Thu, 8 Nov 2018 00:21:05 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41851 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726435AbeKHFVF (ORCPT ); Thu, 8 Nov 2018 00:21:05 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTp8-00070Q-DB; Wed, 07 Nov 2018 20:49:10 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 06/23] x86/fpu: Always init the `state' in fpu__clear() Date: Wed, 7 Nov 2018 20:48:41 +0100 Message-Id: <20181107194858.9380-7-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP fpu__clear() only initializes the `state' if the FPU is present. This initialisation is also required for the FPU-less system and takes place math_emulate(). Since fpu__initialize() only performs the initialization if ->initialized is zero it does not matter that it is invoked each time an opcode is emulated. It makes the removal of ->initialized easier if the struct is also initialized in FPU-less case at the same time. Move fpu__initialize() before the FPU check so it is also performed in FPU-less case. Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/include/asm/fpu/internal.h | 1 - arch/x86/kernel/fpu/core.c | 5 ++--- arch/x86/math-emu/fpu_entry.c | 3 --- 3 files changed, 2 insertions(+), 7 deletions(-) diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 32ea458f13b5c..971fb0988d56f 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -24,7 +24,6 @@ /* * High level FPU state handling functions: */ -extern void fpu__initialize(struct fpu *fpu); extern void fpu__prepare_read(struct fpu *fpu); extern void fpu__prepare_write(struct fpu *fpu); extern void fpu__save(struct fpu *fpu); diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index b7d9b19ab8116..8391debc57265 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -225,7 +225,7 @@ int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu) * Activate the current task's in-memory FPU context, * if it has not been used before: */ -void fpu__initialize(struct fpu *fpu) +static void fpu__initialize(struct fpu *fpu) { WARN_ON_FPU(fpu != ¤t->thread.fpu); @@ -238,7 +238,6 @@ void fpu__initialize(struct fpu *fpu) fpu->initialized = 1; } } -EXPORT_SYMBOL_GPL(fpu__initialize); /* * This function must be called before we read a task's fpstate. @@ -367,8 +366,8 @@ void fpu__clear(struct fpu *fpu) /* * Make sure fpstate is cleared and initialized. */ + fpu__initialize(fpu); if (static_cpu_has(X86_FEATURE_FPU)) { - fpu__initialize(fpu); user_fpu_begin(); copy_init_fpstate_to_fpregs(); } diff --git a/arch/x86/math-emu/fpu_entry.c b/arch/x86/math-emu/fpu_entry.c index 9e2ba7e667f61..a873da6b46d6b 100644 --- a/arch/x86/math-emu/fpu_entry.c +++ b/arch/x86/math-emu/fpu_entry.c @@ -113,9 +113,6 @@ void math_emulate(struct math_emu_info *info) unsigned long code_base = 0; unsigned long code_limit = 0; /* Initialized to stop compiler warnings */ struct desc_struct code_descriptor; - struct fpu *fpu = ¤t->thread.fpu; - - fpu__initialize(fpu); #ifdef RE_ENTRANT_CHECKING if (emulating) { From patchwork Wed Nov 7 19:48:42 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672983 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id DDE1215A6 for ; Wed, 7 Nov 2018 19:51:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D10B22CFEC for ; Wed, 7 Nov 2018 19:51:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C54472D020; Wed, 7 Nov 2018 19:51:42 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 611082D011 for ; Wed, 7 Nov 2018 19:51:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727214AbeKHFVF (ORCPT ); Thu, 8 Nov 2018 00:21:05 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41861 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725953AbeKHFVF (ORCPT ); Thu, 8 Nov 2018 00:21:05 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTp9-00070Q-7D; Wed, 07 Nov 2018 20:49:11 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 07/23] x86/fpu: Remove fpu->initialized usage in copy_fpstate_to_sigframe() Date: Wed, 7 Nov 2018 20:48:42 +0100 Message-Id: <20181107194858.9380-8-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Since ->initialized is always true for user tasks and kernel threads don't get this far, we always save the registers directly to userspace. Remove check for ->initialized because it is always true and remove the false condition. Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/kernel/fpu/signal.c | 30 ++++++------------------------ 1 file changed, 6 insertions(+), 24 deletions(-) diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 5777ee0c32fed..30e65085dc4d9 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -157,7 +157,6 @@ static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf) int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size) { struct fpu *fpu = ¤t->thread.fpu; - struct xregs_state *xsave = &fpu->state.xsave; struct task_struct *tsk = current; int ia32_fxstate = (buf != buf_fx); @@ -172,29 +171,12 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size) sizeof(struct user_i387_ia32_struct), NULL, (struct _fpstate_32 __user *) buf) ? -1 : 1; - if (fpu->initialized || using_compacted_format()) { - /* Save the live register state to the user directly. */ - if (copy_fpregs_to_sigframe(buf_fx)) - return -1; - /* Update the thread's fxstate to save the fsave header. */ - if (ia32_fxstate) - copy_fxregs_to_kernel(fpu); - } else { - /* - * It is a *bug* if kernel uses compacted-format for xsave - * area and we copy it out directly to a signal frame. It - * should have been handled above by saving the registers - * directly. - */ - if (boot_cpu_has(X86_FEATURE_XSAVES)) { - WARN_ONCE(1, "x86/fpu: saving compacted-format xsave area to a signal frame!\n"); - return -1; - } - - fpstate_sanitize_xstate(fpu); - if (__copy_to_user(buf_fx, xsave, fpu_user_xstate_size)) - return -1; - } + /* Save the live register state to the user directly. */ + if (copy_fpregs_to_sigframe(buf_fx)) + return -1; + /* Update the thread's fxstate to save the fsave header. */ + if (ia32_fxstate) + copy_fxregs_to_kernel(fpu); /* Save the fsave header for the 32-bit frames. */ if ((ia32_fxstate || !use_fxsr()) && save_fsave_header(tsk, buf)) From patchwork Wed Nov 7 19:48:43 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672949 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5122813AD for ; Wed, 7 Nov 2018 19:49:24 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 40B892CF64 for ; Wed, 7 Nov 2018 19:49:24 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 339DD2C888; Wed, 7 Nov 2018 19:49:24 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 16C822C888 for ; Wed, 7 Nov 2018 19:49:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727395AbeKHFVL (ORCPT ); Thu, 8 Nov 2018 00:21:11 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41870 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727272AbeKHFVK (ORCPT ); Thu, 8 Nov 2018 00:21:10 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTpA-00070Q-8O; Wed, 07 Nov 2018 20:49:12 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 08/23] x86/fpu: Remove fpu->initialized Date: Wed, 7 Nov 2018 20:48:43 +0100 Message-Id: <20181107194858.9380-9-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The `initialized' member of the fpu struct is always set to one user tasks and zero for kernel tasks. This avoids saving/restoring the FPU registers for kernel threads. By dropping that member the context switch time between kernel-threads increases because the FPU registers are needlessly stored and restored. The following context switch 1. TaskA -> kernel thread1 2. kernel thread1 -> TaskA will restore TaskA's FPU registers in step 2. This wasn't the case earlier because they would not have been destroyed by the kernel thread. This means now fpu_fpregs_owner_ctx points always to current's FPU struct (even for kernel threads). One different behaviour: Since the FPU registers are now restored for kernel threads, they will have PKRU=0. Before this change, the kernel thread had a random value (inherited from the previous user task). The increased context switch time will be reverted once the FPU registers are restored on return to userland. Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/ia32/ia32_signal.c | 17 +++---- arch/x86/include/asm/fpu/internal.h | 17 ++++--- arch/x86/include/asm/fpu/types.h | 9 ---- arch/x86/include/asm/trace/fpu.h | 5 +- arch/x86/kernel/fpu/core.c | 77 +++++++---------------------- arch/x86/kernel/fpu/init.c | 2 - arch/x86/kernel/fpu/regset.c | 19 ++----- arch/x86/kernel/fpu/xstate.c | 2 - arch/x86/kernel/process_32.c | 4 +- arch/x86/kernel/process_64.c | 4 +- arch/x86/kernel/signal.c | 17 +++---- arch/x86/mm/pkeys.c | 7 +-- 12 files changed, 51 insertions(+), 129 deletions(-) diff --git a/arch/x86/ia32/ia32_signal.c b/arch/x86/ia32/ia32_signal.c index 86b1341cba9ac..eb215ac5d9f46 100644 --- a/arch/x86/ia32/ia32_signal.c +++ b/arch/x86/ia32/ia32_signal.c @@ -216,8 +216,7 @@ static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size, void __user **fpstate) { - struct fpu *fpu = ¤t->thread.fpu; - unsigned long sp; + unsigned long sp, fx_aligned, math_size; /* Default to using normal stack */ sp = regs->sp; @@ -231,15 +230,11 @@ static void __user *get_sigframe(struct ksignal *ksig, struct pt_regs *regs, ksig->ka.sa.sa_restorer) sp = (unsigned long) ksig->ka.sa.sa_restorer; - if (fpu->initialized) { - unsigned long fx_aligned, math_size; - - sp = fpu__alloc_mathframe(sp, 1, &fx_aligned, &math_size); - *fpstate = (struct _fpstate_32 __user *) sp; - if (copy_fpstate_to_sigframe(*fpstate, (void __user *)fx_aligned, - math_size) < 0) - return (void __user *) -1L; - } + sp = fpu__alloc_mathframe(sp, 1, &fx_aligned, &math_size); + *fpstate = (struct _fpstate_32 __user *) sp; + if (copy_fpstate_to_sigframe(*fpstate, (void __user *)fx_aligned, + math_size) < 0) + return (void __user *) -1L; sp -= frame_size; /* Align the stack pointer according to the i386 ABI, diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 971fb0988d56f..d7ef8ac8b17eb 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -526,7 +526,7 @@ static inline void fpregs_activate(struct fpu *fpu) static inline void switch_fpu_prepare(struct fpu *old_fpu, int cpu) { - if (static_cpu_has(X86_FEATURE_FPU) && old_fpu->initialized) { + if (static_cpu_has(X86_FEATURE_FPU)) { if (!copy_fpregs_to_fpstate(old_fpu)) old_fpu->last_cpu = -1; else @@ -534,8 +534,7 @@ switch_fpu_prepare(struct fpu *old_fpu, int cpu) /* But leave fpu_fpregs_owner_ctx! */ trace_x86_fpu_regs_deactivated(old_fpu); - } else - old_fpu->last_cpu = -1; + } } /* @@ -548,12 +547,14 @@ switch_fpu_prepare(struct fpu *old_fpu, int cpu) */ static inline void switch_fpu_finish(struct fpu *new_fpu, int cpu) { - bool preload = static_cpu_has(X86_FEATURE_FPU) && - new_fpu->initialized; + if (static_cpu_has(X86_FEATURE_FPU)) { + if (!fpregs_state_valid(new_fpu, cpu)) { + if (current->mm) + copy_kernel_to_fpregs(&new_fpu->state); + else + copy_kernel_to_fpregs(&init_fpstate); + } - if (preload) { - if (!fpregs_state_valid(new_fpu, cpu)) - copy_kernel_to_fpregs(&new_fpu->state); fpregs_activate(new_fpu); } } diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h index 202c53918ecfa..c5a6edd92de4f 100644 --- a/arch/x86/include/asm/fpu/types.h +++ b/arch/x86/include/asm/fpu/types.h @@ -293,15 +293,6 @@ struct fpu { */ unsigned int last_cpu; - /* - * @initialized: - * - * This flag indicates whether this context is initialized: if the task - * is not running then we can restore from this context, if the task - * is running then we should save into this context. - */ - unsigned char initialized; - /* * @state: * diff --git a/arch/x86/include/asm/trace/fpu.h b/arch/x86/include/asm/trace/fpu.h index 069c04be15076..bd65f6ba950f8 100644 --- a/arch/x86/include/asm/trace/fpu.h +++ b/arch/x86/include/asm/trace/fpu.h @@ -13,22 +13,19 @@ DECLARE_EVENT_CLASS(x86_fpu, TP_STRUCT__entry( __field(struct fpu *, fpu) - __field(bool, initialized) __field(u64, xfeatures) __field(u64, xcomp_bv) ), TP_fast_assign( __entry->fpu = fpu; - __entry->initialized = fpu->initialized; if (boot_cpu_has(X86_FEATURE_OSXSAVE)) { __entry->xfeatures = fpu->state.xsave.header.xfeatures; __entry->xcomp_bv = fpu->state.xsave.header.xcomp_bv; } ), - TP_printk("x86/fpu: %p initialized: %d xfeatures: %llx xcomp_bv: %llx", + TP_printk("x86/fpu: %p xfeatures: %llx xcomp_bv: %llx", __entry->fpu, - __entry->initialized, __entry->xfeatures, __entry->xcomp_bv ) diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 8391debc57265..2ed82c6e646b9 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -101,15 +101,7 @@ void __kernel_fpu_begin(void) kernel_fpu_disable(); - if (fpu->initialized) { - /* - * Ignore return value -- we don't care if reg state - * is clobbered. - */ - copy_fpregs_to_fpstate(fpu); - } else { - __cpu_invalidate_fpregs_state(); - } + copy_fpregs_to_fpstate(fpu); } EXPORT_SYMBOL(__kernel_fpu_begin); @@ -117,8 +109,7 @@ void __kernel_fpu_end(void) { struct fpu *fpu = ¤t->thread.fpu; - if (fpu->initialized) - copy_kernel_to_fpregs(&fpu->state); + copy_kernel_to_fpregs(&fpu->state); kernel_fpu_enable(); } @@ -149,10 +140,9 @@ void fpu__save(struct fpu *fpu) preempt_disable(); trace_x86_fpu_before_save(fpu); - if (fpu->initialized) { - if (!copy_fpregs_to_fpstate(fpu)) { - copy_kernel_to_fpregs(&fpu->state); - } + + if (!copy_fpregs_to_fpstate(fpu)) { + copy_kernel_to_fpregs(&fpu->state); } trace_x86_fpu_after_save(fpu); preempt_enable(); @@ -192,7 +182,7 @@ int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu) { dst_fpu->last_cpu = -1; - if (!src_fpu->initialized || !static_cpu_has(X86_FEATURE_FPU)) + if (!static_cpu_has(X86_FEATURE_FPU)) return 0; WARN_ON_FPU(src_fpu != ¤t->thread.fpu); @@ -229,14 +219,10 @@ static void fpu__initialize(struct fpu *fpu) { WARN_ON_FPU(fpu != ¤t->thread.fpu); - if (!fpu->initialized) { - fpstate_init(&fpu->state); - trace_x86_fpu_init_state(fpu); + fpstate_init(&fpu->state); + trace_x86_fpu_init_state(fpu); - trace_x86_fpu_activate_state(fpu); - /* Safe to do for the current task: */ - fpu->initialized = 1; - } + trace_x86_fpu_activate_state(fpu); } /* @@ -249,32 +235,20 @@ static void fpu__initialize(struct fpu *fpu) * * - or it's called for stopped tasks (ptrace), in which case the * registers were already saved by the context-switch code when - * the task scheduled out - we only have to initialize the registers - * if they've never been initialized. + * the task scheduled out. * * If the task has used the FPU before then save it. */ void fpu__prepare_read(struct fpu *fpu) { - if (fpu == ¤t->thread.fpu) { + if (fpu == ¤t->thread.fpu) fpu__save(fpu); - } else { - if (!fpu->initialized) { - fpstate_init(&fpu->state); - trace_x86_fpu_init_state(fpu); - - trace_x86_fpu_activate_state(fpu); - /* Safe to do for current and for stopped child tasks: */ - fpu->initialized = 1; - } - } } /* * This function must be called before we write a task's fpstate. * - * If the task has used the FPU before then invalidate any cached FPU registers. - * If the task has not used the FPU before then initialize its fpstate. + * Invalidate any cached FPU registers. * * After this function call, after registers in the fpstate are * modified and the child task has woken up, the child task will @@ -291,17 +265,8 @@ void fpu__prepare_write(struct fpu *fpu) */ WARN_ON_FPU(fpu == ¤t->thread.fpu); - if (fpu->initialized) { - /* Invalidate any cached state: */ - __fpu_invalidate_fpregs_state(fpu); - } else { - fpstate_init(&fpu->state); - trace_x86_fpu_init_state(fpu); - - trace_x86_fpu_activate_state(fpu); - /* Safe to do for stopped child tasks: */ - fpu->initialized = 1; - } + /* Invalidate any cached state: */ + __fpu_invalidate_fpregs_state(fpu); } /* @@ -318,17 +283,13 @@ void fpu__drop(struct fpu *fpu) preempt_disable(); if (fpu == ¤t->thread.fpu) { - if (fpu->initialized) { - /* Ignore delayed exceptions from user space */ - asm volatile("1: fwait\n" - "2:\n" - _ASM_EXTABLE(1b, 2b)); - fpregs_deactivate(fpu); - } + /* Ignore delayed exceptions from user space */ + asm volatile("1: fwait\n" + "2:\n" + _ASM_EXTABLE(1b, 2b)); + fpregs_deactivate(fpu); } - fpu->initialized = 0; - trace_x86_fpu_dropped(fpu); preempt_enable(); diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c index 6abd83572b016..20d8fa7124c77 100644 --- a/arch/x86/kernel/fpu/init.c +++ b/arch/x86/kernel/fpu/init.c @@ -239,8 +239,6 @@ static void __init fpu__init_system_ctx_switch(void) WARN_ON_FPU(!on_boot_cpu); on_boot_cpu = 0; - - WARN_ON_FPU(current->thread.fpu.initialized); } /* diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c index 5dbc099178a88..d652b939ccfb5 100644 --- a/arch/x86/kernel/fpu/regset.c +++ b/arch/x86/kernel/fpu/regset.c @@ -15,16 +15,12 @@ */ int regset_fpregs_active(struct task_struct *target, const struct user_regset *regset) { - struct fpu *target_fpu = &target->thread.fpu; - - return target_fpu->initialized ? regset->n : 0; + return regset->n; } int regset_xregset_fpregs_active(struct task_struct *target, const struct user_regset *regset) { - struct fpu *target_fpu = &target->thread.fpu; - - if (boot_cpu_has(X86_FEATURE_FXSR) && target_fpu->initialized) + if (boot_cpu_has(X86_FEATURE_FXSR)) return regset->n; else return 0; @@ -370,16 +366,9 @@ int fpregs_set(struct task_struct *target, const struct user_regset *regset, int dump_fpu(struct pt_regs *regs, struct user_i387_struct *ufpu) { struct task_struct *tsk = current; - struct fpu *fpu = &tsk->thread.fpu; - int fpvalid; - fpvalid = fpu->initialized; - if (fpvalid) - fpvalid = !fpregs_get(tsk, NULL, - 0, sizeof(struct user_i387_ia32_struct), - ufpu, NULL); - - return fpvalid; + return !fpregs_get(tsk, NULL, 0, sizeof(struct user_i387_ia32_struct), + ufpu, NULL); } EXPORT_SYMBOL(dump_fpu); diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 9dc0a2c8c2755..a2041961f3008 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -894,8 +894,6 @@ const void *get_xsave_field_ptr(int xsave_state) { struct fpu *fpu = ¤t->thread.fpu; - if (!fpu->initialized) - return NULL; /* * fpu__save() takes the CPU's xstate registers * and saves them off to the 'fpu memory buffer. diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index b8a935adc96fc..5c99e49c0d392 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -292,10 +292,10 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) if (prev->gs | next->gs) lazy_load_gs(next->gs); - switch_fpu_finish(next_fpu, cpu); - this_cpu_write(current_task, next_p); + switch_fpu_finish(next_fpu, cpu); + /* Load the Intel cache allocation PQR MSR. */ intel_rdt_sched_in(); diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index cf2c157714594..4fd0dfa5bd83e 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -604,14 +604,14 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) x86_fsgsbase_load(prev, next); - switch_fpu_finish(next_fpu, cpu); - /* * Switch the PDA and FPU contexts. */ this_cpu_write(current_task, next_p); this_cpu_write(cpu_current_top_of_stack, task_top_of_stack(next_p)); + switch_fpu_finish(next_fpu, cpu); + /* Reload sp0. */ update_task_stack(next_p); diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c index 92a3b312a53c4..2687e698c31fc 100644 --- a/arch/x86/kernel/signal.c +++ b/arch/x86/kernel/signal.c @@ -246,7 +246,7 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, unsigned long sp = regs->sp; unsigned long buf_fx = 0; int onsigstack = on_sig_stack(sp); - struct fpu *fpu = ¤t->thread.fpu; + int ret; /* redzone */ if (IS_ENABLED(CONFIG_X86_64)) @@ -265,11 +265,9 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, sp = (unsigned long) ka->sa.sa_restorer; } - if (fpu->initialized) { - sp = fpu__alloc_mathframe(sp, IS_ENABLED(CONFIG_X86_32), - &buf_fx, &math_size); - *fpstate = (void __user *)sp; - } + sp = fpu__alloc_mathframe(sp, IS_ENABLED(CONFIG_X86_32), + &buf_fx, &math_size); + *fpstate = (void __user *)sp; sp = align_sigframe(sp - frame_size); @@ -281,8 +279,8 @@ get_sigframe(struct k_sigaction *ka, struct pt_regs *regs, size_t frame_size, return (void __user *)-1L; /* save i387 and extended state */ - if (fpu->initialized && - copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size) < 0) + ret = copy_fpstate_to_sigframe(*fpstate, (void __user *)buf_fx, math_size); + if (ret < 0) return (void __user *)-1L; return (void __user *)sp; @@ -763,8 +761,7 @@ handle_signal(struct ksignal *ksig, struct pt_regs *regs) /* * Ensure the signal handler starts with the new fpu state. */ - if (fpu->initialized) - fpu__clear(fpu); + fpu__clear(fpu); } signal_setup_done(failed, ksig, stepping); } diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c index 6e98e0a7c9231..0af3ece18f113 100644 --- a/arch/x86/mm/pkeys.c +++ b/arch/x86/mm/pkeys.c @@ -39,17 +39,12 @@ int __execute_only_pkey(struct mm_struct *mm) * dance to set PKRU if we do not need to. Check it * first and assume that if the execute-only pkey is * write-disabled that we do not have to set it - * ourselves. We need preempt off so that nobody - * can make fpregs inactive. + * ourselves. */ - preempt_disable(); if (!need_to_set_mm_pkey && - current->thread.fpu.initialized && !__pkru_allows_read(read_pkru(), execute_only_pkey)) { - preempt_enable(); return execute_only_pkey; } - preempt_enable(); /* * Set up PKRU so that it denies access for everything From patchwork Wed Nov 7 19:48:44 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672977 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A0E3C13AD for ; Wed, 7 Nov 2018 19:51:16 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 928EA2CFE9 for ; Wed, 7 Nov 2018 19:51:16 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 864F22D015; Wed, 7 Nov 2018 19:51:16 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 1FF5C2CFE6 for ; Wed, 7 Nov 2018 19:51:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727480AbeKHFVM (ORCPT ); Thu, 8 Nov 2018 00:21:12 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41895 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726948AbeKHFVM (ORCPT ); Thu, 8 Nov 2018 00:21:12 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTpB-00070Q-Ec; Wed, 07 Nov 2018 20:49:13 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 09/23] x86/fpu: Remove user_fpu_begin() Date: Wed, 7 Nov 2018 20:48:44 +0100 Message-Id: <20181107194858.9380-10-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP user_fpu_begin() sets fpu_fpregs_owner_ctx to task's fpu struct. This is always the case since there is no lazy FPU anymore. fpu_fpregs_owner_ctx is used during context switch to decide if it needs to load the saved registers or if the currently loaded registers are valid. This field is always updated on context switch so setting it manually has no benefit. Before the removal of the ->initialized member, fpu_fpregs_owner_ctx wouldn't be updated for kernel threads. But kernel threads don't use the fpu struct so again, user_fpu_begin() would not make a difference in user context (and would be wrong in kernel context). Remove user_fpu_begin(), it does not change fpu_fpregs_owner_ctx's content. Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/include/asm/fpu/internal.h | 17 ----------------- arch/x86/kernel/fpu/core.c | 4 +--- arch/x86/kernel/fpu/signal.c | 1 - 3 files changed, 1 insertion(+), 21 deletions(-) diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index d7ef8ac8b17eb..d7f9e14c73c19 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -559,23 +559,6 @@ static inline void switch_fpu_finish(struct fpu *new_fpu, int cpu) } } -/* - * Needs to be preemption-safe. - * - * NOTE! user_fpu_begin() must be used only immediately before restoring - * the save state. It does not do any saving/restoring on its own. In - * lazy FPU mode, it is just an optimization to avoid a #NM exception, - * the task can lose the FPU right after preempt_enable(). - */ -static inline void user_fpu_begin(void) -{ - struct fpu *fpu = ¤t->thread.fpu; - - preempt_disable(); - fpregs_activate(fpu); - preempt_enable(); -} - /* * MXCSR and XCR definitions: */ diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 2ed82c6e646b9..02bbd40fe1e95 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -328,10 +328,8 @@ void fpu__clear(struct fpu *fpu) * Make sure fpstate is cleared and initialized. */ fpu__initialize(fpu); - if (static_cpu_has(X86_FEATURE_FPU)) { - user_fpu_begin(); + if (static_cpu_has(X86_FEATURE_FPU)) copy_init_fpstate_to_fpregs(); - } } /* diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 30e65085dc4d9..f61f4d804537a 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -328,7 +328,6 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) * For 64-bit frames and 32-bit fsave frames, restore the user * state to the registers directly (with exceptions handled). */ - user_fpu_begin(); if (copy_user_to_fpregs_zeroing(buf_fx, xfeatures, fx_only)) { fpu__clear(fpu); return -1; From patchwork Wed Nov 7 19:48:45 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672979 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 04DC213AD for ; Wed, 7 Nov 2018 19:51:29 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E6BBE2D01C for ; Wed, 7 Nov 2018 19:51:28 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E53372D012; Wed, 7 Nov 2018 19:51:28 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 931782D02D for ; Wed, 7 Nov 2018 19:51:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727344AbeKHFVL (ORCPT ); Thu, 8 Nov 2018 00:21:11 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41888 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725953AbeKHFVK (ORCPT ); Thu, 8 Nov 2018 00:21:10 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTpC-00070Q-Dx; Wed, 07 Nov 2018 20:49:14 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 10/23] x86/entry: Remove _TIF_ALLWORK_MASK Date: Wed, 7 Nov 2018 20:48:45 +0100 Message-Id: <20181107194858.9380-11-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP There is no user of _TIF_ALLWORK_MASK since commit 21d375b6b34ff ("x86/entry/64: Remove the SYSCALL64 fast path"). Remove unused define _TIF_ALLWORK_MASK. Reviewed-by: Borislav Petkov Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/include/asm/thread_info.h | 8 -------- 1 file changed, 8 deletions(-) diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index 2ff2a30a264f4..cd6920674b905 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -136,14 +136,6 @@ struct thread_info { _TIF_SECCOMP | _TIF_SYSCALL_TRACEPOINT | \ _TIF_NOHZ) -/* work to do on any return to user space */ -#define _TIF_ALLWORK_MASK \ - (_TIF_SYSCALL_TRACE | _TIF_NOTIFY_RESUME | _TIF_SIGPENDING | \ - _TIF_NEED_RESCHED | _TIF_SINGLESTEP | _TIF_SYSCALL_EMU | \ - _TIF_SYSCALL_AUDIT | _TIF_USER_RETURN_NOTIFY | _TIF_UPROBE | \ - _TIF_PATCH_PENDING | _TIF_NOHZ | _TIF_SYSCALL_TRACEPOINT | \ - _TIF_FSCHECK) - /* flags to check in __switch_to() */ #define _TIF_WORK_CTXSW \ (_TIF_IO_BITMAP|_TIF_NOCPUID|_TIF_NOTSC|_TIF_BLOCKSTEP|_TIF_SSBD) From patchwork Wed Nov 7 19:48:46 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672975 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 20EBA15A6 for ; Wed, 7 Nov 2018 19:51:12 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 11BCF2CFD1 for ; Wed, 7 Nov 2018 19:51:12 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 100982CFF9; Wed, 7 Nov 2018 19:51:12 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8A8422CFF4 for ; Wed, 7 Nov 2018 19:51:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727529AbeKHFVM (ORCPT ); Thu, 8 Nov 2018 00:21:12 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41899 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727337AbeKHFVM (ORCPT ); Thu, 8 Nov 2018 00:21:12 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTpD-00070Q-C9; Wed, 07 Nov 2018 20:49:16 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 11/23] x86/fpu: Add (__)make_fpregs_active helpers Date: Wed, 7 Nov 2018 20:48:46 +0100 Message-Id: <20181107194858.9380-12-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Rik van Riel Add helper function that ensures the floating point registers for the current task are active. Use with preemption disabled. Signed-off-by: Rik van Riel Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/include/asm/fpu/api.h | 11 +++++++++++ arch/x86/include/asm/fpu/internal.h | 26 ++++++++++++++++---------- 2 files changed, 27 insertions(+), 10 deletions(-) diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h index a9caac9d4a729..8c03b42416656 100644 --- a/arch/x86/include/asm/fpu/api.h +++ b/arch/x86/include/asm/fpu/api.h @@ -10,6 +10,7 @@ #ifndef _ASM_X86_FPU_API_H #define _ASM_X86_FPU_API_H +#include /* * Careful: __kernel_fpu_begin/end() must be called with preempt disabled @@ -27,6 +28,16 @@ extern void kernel_fpu_begin(void); extern void kernel_fpu_end(void); extern bool irq_fpu_usable(void); +static inline void __fpregs_changes_begin(void) +{ + preempt_disable(); +} + +static inline void __fpregs_changes_end(void) +{ + preempt_enable(); +} + /* * Query the presence of one or more xfeatures. Works on any legacy CPU as well. * diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index d7f9e14c73c19..260cd4f4ba2bb 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -512,6 +512,20 @@ static inline void fpregs_activate(struct fpu *fpu) trace_x86_fpu_regs_activated(fpu); } +/* + * Load the FPU state for the current task. Call with preemption disabled. + */ +static inline void __fpregs_load_activate(struct fpu *fpu, int cpu) +{ + if (!fpregs_state_valid(fpu, cpu)) { + if (current->mm) + copy_kernel_to_fpregs(&fpu->state); + else + copy_kernel_to_fpregs(&init_fpstate); + } + fpregs_activate(fpu); +} + /* * FPU state switching for scheduling. * @@ -547,16 +561,8 @@ switch_fpu_prepare(struct fpu *old_fpu, int cpu) */ static inline void switch_fpu_finish(struct fpu *new_fpu, int cpu) { - if (static_cpu_has(X86_FEATURE_FPU)) { - if (!fpregs_state_valid(new_fpu, cpu)) { - if (current->mm) - copy_kernel_to_fpregs(&new_fpu->state); - else - copy_kernel_to_fpregs(&init_fpstate); - } - - fpregs_activate(new_fpu); - } + if (static_cpu_has(X86_FEATURE_FPU)) + __fpregs_load_activate(new_fpu, cpu); } /* From patchwork Wed Nov 7 19:48:47 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672971 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5E51B13AD for ; Wed, 7 Nov 2018 19:50:52 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 51A522CF8A for ; Wed, 7 Nov 2018 19:50:52 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 45E182CFE5; Wed, 7 Nov 2018 19:50:52 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D0B8C2CF96 for ; Wed, 7 Nov 2018 19:50:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727615AbeKHFVP (ORCPT ); Thu, 8 Nov 2018 00:21:15 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41908 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727272AbeKHFVO (ORCPT ); Thu, 8 Nov 2018 00:21:14 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTpF-00070Q-Di; Wed, 07 Nov 2018 20:49:17 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 12/23] x86/fpu: Make __raw_xsave_addr() use feature number instead of mask Date: Wed, 7 Nov 2018 20:48:47 +0100 Message-Id: <20181107194858.9380-13-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Most users of __raw_xsave_addr() use a feature number, shift it to a mask and then __raw_xsave_addr() shifts it back to the feature number. Make __raw_xsave_addr() use the feature number as argument. Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/kernel/fpu/xstate.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-) diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index a2041961f3008..3dfe3627deaf6 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -805,22 +805,20 @@ void fpu__resume_cpu(void) } /* - * Given an xstate feature mask, calculate where in the xsave + * Given an xstate feature nr, calculate where in the xsave * buffer the state is. Callers should ensure that the buffer * is valid. * * Note: does not work for compacted buffers. */ -void *__raw_xsave_addr(struct xregs_state *xsave, int xstate_feature_mask) +static void *__raw_xsave_addr(struct xregs_state *xsave, int xfeature_nr) { - int feature_nr = fls64(xstate_feature_mask) - 1; - - if (!xfeature_enabled(feature_nr)) { + if (!xfeature_enabled(xfeature_nr)) { WARN_ON_FPU(1); return NULL; } - return (void *)xsave + xstate_comp_offsets[feature_nr]; + return (void *)xsave + xstate_comp_offsets[xfeature_nr]; } /* * Given the xsave area and a state inside, this function returns the @@ -842,6 +840,7 @@ void *__raw_xsave_addr(struct xregs_state *xsave, int xstate_feature_mask) */ void *get_xsave_addr(struct xregs_state *xsave, int xstate_feature) { + int xfeature_nr; /* * Do we even *have* xsave state? */ @@ -869,7 +868,8 @@ void *get_xsave_addr(struct xregs_state *xsave, int xstate_feature) if (!(xsave->header.xfeatures & xstate_feature)) return NULL; - return __raw_xsave_addr(xsave, xstate_feature); + xfeature_nr = fls64(xstate_feature) - 1; + return __raw_xsave_addr(xsave, xfeature_nr); } EXPORT_SYMBOL_GPL(get_xsave_addr); @@ -1016,7 +1016,7 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int of * Copy only in-use xstates: */ if ((header.xfeatures >> i) & 1) { - void *src = __raw_xsave_addr(xsave, 1 << i); + void *src = __raw_xsave_addr(xsave, i); offset = xstate_offsets[i]; size = xstate_sizes[i]; @@ -1102,7 +1102,7 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i * Copy only in-use xstates: */ if ((header.xfeatures >> i) & 1) { - void *src = __raw_xsave_addr(xsave, 1 << i); + void *src = __raw_xsave_addr(xsave, i); offset = xstate_offsets[i]; size = xstate_sizes[i]; @@ -1159,7 +1159,7 @@ int copy_kernel_to_xstate(struct xregs_state *xsave, const void *kbuf) u64 mask = ((u64)1 << i); if (hdr.xfeatures & mask) { - void *dst = __raw_xsave_addr(xsave, 1 << i); + void *dst = __raw_xsave_addr(xsave, i); offset = xstate_offsets[i]; size = xstate_sizes[i]; @@ -1213,7 +1213,7 @@ int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf) u64 mask = ((u64)1 << i); if (hdr.xfeatures & mask) { - void *dst = __raw_xsave_addr(xsave, 1 << i); + void *dst = __raw_xsave_addr(xsave, i); offset = xstate_offsets[i]; size = xstate_sizes[i]; From patchwork Wed Nov 7 19:48:48 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672967 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CF59713AD for ; Wed, 7 Nov 2018 19:50:39 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C095A2CF9B for ; Wed, 7 Nov 2018 19:50:39 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BE1AF2CFCB; Wed, 7 Nov 2018 19:50:39 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CA37E2CF9B for ; Wed, 7 Nov 2018 19:50:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727735AbeKHFVQ (ORCPT ); Thu, 8 Nov 2018 00:21:16 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41912 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727579AbeKHFVP (ORCPT ); Thu, 8 Nov 2018 00:21:15 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTpG-00070Q-PV; Wed, 07 Nov 2018 20:49:19 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 13/23] x86/fpu: Make get_xsave_field_ptr() and get_xsave_addr() use feature number instead of mask Date: Wed, 7 Nov 2018 20:48:48 +0100 Message-Id: <20181107194858.9380-14-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP After changing the argument of __raw_xsave_addr() from a mask to number Dave suggested to check if it makes sense to do the same for get_xsave_addr(). As it turns out it does. Only get_xsave_addr() needs the mask to check if the requested feature is part of what is support/saved and then uses the number again. The shift operation is cheaper compared to "find last bit set". Also, the feature number uses less opcode space compared to the mask :) Make get_xsave_addr() argument a xfeature number instead of mask and fix up its callers. As part of this use xfeature_nr and xfeature_mask consistently. This results in changes to the kvm code as: feature -> xfeature_mask index -> xfeature_nr Suggested-by: Dave Hansen Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/include/asm/fpu/xstate.h | 4 ++-- arch/x86/kernel/fpu/xstate.c | 23 +++++++++++------------ arch/x86/kernel/traps.c | 2 +- arch/x86/kvm/x86.c | 28 ++++++++++++++-------------- arch/x86/mm/mpx.c | 6 +++--- 5 files changed, 31 insertions(+), 32 deletions(-) diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index 48581988d78c7..fbe41f808e5d8 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -46,8 +46,8 @@ extern void __init update_regset_xstate_info(unsigned int size, u64 xstate_mask); void fpu__xstate_clear_all_cpu_caps(void); -void *get_xsave_addr(struct xregs_state *xsave, int xstate); -const void *get_xsave_field_ptr(int xstate_field); +void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr); +const void *get_xsave_field_ptr(int xfeature_nr); int using_compacted_format(void); int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int offset, unsigned int size); int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned int offset, unsigned int size); diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 3dfe3627deaf6..375226055a413 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -832,15 +832,15 @@ static void *__raw_xsave_addr(struct xregs_state *xsave, int xfeature_nr) * * Inputs: * xstate: the thread's storage area for all FPU data - * xstate_feature: state which is defined in xsave.h (e.g. - * XFEATURE_MASK_FP, XFEATURE_MASK_SSE, etc...) + * xfeature_nr: state which is defined in xsave.h (e.g. XFEATURE_FP, + * XFEATURE_SSE, etc...) * Output: * address of the state in the xsave area, or NULL if the * field is not present in the xsave buffer. */ -void *get_xsave_addr(struct xregs_state *xsave, int xstate_feature) +void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr) { - int xfeature_nr; + u64 xfeature_mask = 1ULL << xfeature_nr; /* * Do we even *have* xsave state? */ @@ -852,11 +852,11 @@ void *get_xsave_addr(struct xregs_state *xsave, int xstate_feature) * have not enabled. Remember that pcntxt_mask is * what we write to the XCR0 register. */ - WARN_ONCE(!(xfeatures_mask & xstate_feature), + WARN_ONCE(!(xfeatures_mask & xfeature_mask), "get of unsupported state"); /* * This assumes the last 'xsave*' instruction to - * have requested that 'xstate_feature' be saved. + * have requested that 'xfeature_mask' be saved. * If it did not, we might be seeing and old value * of the field in the buffer. * @@ -865,10 +865,9 @@ void *get_xsave_addr(struct xregs_state *xsave, int xstate_feature) * or because the "init optimization" caused it * to not be saved. */ - if (!(xsave->header.xfeatures & xstate_feature)) + if (!(xsave->header.xfeatures & xfeature_mask)) return NULL; - xfeature_nr = fls64(xstate_feature) - 1; return __raw_xsave_addr(xsave, xfeature_nr); } EXPORT_SYMBOL_GPL(get_xsave_addr); @@ -884,13 +883,13 @@ EXPORT_SYMBOL_GPL(get_xsave_addr); * Note that this only works on the current task. * * Inputs: - * @xsave_state: state which is defined in xsave.h (e.g. XFEATURE_MASK_FP, - * XFEATURE_MASK_SSE, etc...) + * @xfeature_nr: state which is defined in xsave.h (e.g. XFEATURE_FP, + * XFEATURE_SSE, etc...) * Output: * address of the state in the xsave area or NULL if the state * is not present or is in its 'init state'. */ -const void *get_xsave_field_ptr(int xsave_state) +const void *get_xsave_field_ptr(int xfeature_nr) { struct fpu *fpu = ¤t->thread.fpu; @@ -900,7 +899,7 @@ const void *get_xsave_field_ptr(int xsave_state) */ fpu__save(fpu); - return get_xsave_addr(&fpu->state.xsave, xsave_state); + return get_xsave_addr(&fpu->state.xsave, xfeature_nr); } #ifdef CONFIG_ARCH_HAS_PKEYS diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c index 9b7c4ca8f0a73..626853b2ac344 100644 --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -455,7 +455,7 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code) * which is all zeros which indicates MPX was not * responsible for the exception. */ - bndcsr = get_xsave_field_ptr(XFEATURE_MASK_BNDCSR); + bndcsr = get_xsave_field_ptr(XFEATURE_BNDCSR); if (!bndcsr) goto exit_trap; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 5cd5647120f2b..75301b439b6e4 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -3650,15 +3650,15 @@ static void fill_xsave(u8 *dest, struct kvm_vcpu *vcpu) */ valid = xstate_bv & ~XFEATURE_MASK_FPSSE; while (valid) { - u64 feature = valid & -valid; - int index = fls64(feature) - 1; - void *src = get_xsave_addr(xsave, feature); + u64 xfeature_mask = valid & -valid; + int xfeature_nr = fls64(xfeature_mask) - 1; + void *src = get_xsave_addr(xsave, xfeature_nr); if (src) { u32 size, offset, ecx, edx; - cpuid_count(XSTATE_CPUID, index, + cpuid_count(XSTATE_CPUID, xfeature_nr, &size, &offset, &ecx, &edx); - if (feature == XFEATURE_MASK_PKRU) + if (xfeature_nr == XFEATURE_PKRU) memcpy(dest + offset, &vcpu->arch.pkru, sizeof(vcpu->arch.pkru)); else @@ -3666,7 +3666,7 @@ static void fill_xsave(u8 *dest, struct kvm_vcpu *vcpu) } - valid -= feature; + valid -= xfeature_mask; } } @@ -3693,22 +3693,22 @@ static void load_xsave(struct kvm_vcpu *vcpu, u8 *src) */ valid = xstate_bv & ~XFEATURE_MASK_FPSSE; while (valid) { - u64 feature = valid & -valid; - int index = fls64(feature) - 1; - void *dest = get_xsave_addr(xsave, feature); + u64 xfeature_mask = valid & -valid; + int xfeature_nr = fls64(xfeature_mask) - 1; + void *dest = get_xsave_addr(xsave, xfeature_nr); if (dest) { u32 size, offset, ecx, edx; - cpuid_count(XSTATE_CPUID, index, + cpuid_count(XSTATE_CPUID, xfeature_nr, &size, &offset, &ecx, &edx); - if (feature == XFEATURE_MASK_PKRU) + if (xfeature_nr == XFEATURE_PKRU) memcpy(&vcpu->arch.pkru, src + offset, sizeof(vcpu->arch.pkru)); else memcpy(dest, src + offset, size); } - valid -= feature; + valid -= xfeature_mask; } } @@ -8704,11 +8704,11 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) if (init_event) kvm_put_guest_fpu(vcpu); mpx_state_buffer = get_xsave_addr(&vcpu->arch.guest_fpu.state.xsave, - XFEATURE_MASK_BNDREGS); + XFEATURE_BNDREGS); if (mpx_state_buffer) memset(mpx_state_buffer, 0, sizeof(struct mpx_bndreg_state)); mpx_state_buffer = get_xsave_addr(&vcpu->arch.guest_fpu.state.xsave, - XFEATURE_MASK_BNDCSR); + XFEATURE_BNDCSR); if (mpx_state_buffer) memset(mpx_state_buffer, 0, sizeof(struct mpx_bndcsr)); if (init_event) diff --git a/arch/x86/mm/mpx.c b/arch/x86/mm/mpx.c index 2385538e80656..bcd55cc3050c2 100644 --- a/arch/x86/mm/mpx.c +++ b/arch/x86/mm/mpx.c @@ -142,7 +142,7 @@ int mpx_fault_info(struct mpx_fault_info *info, struct pt_regs *regs) goto err_out; } /* get bndregs field from current task's xsave area */ - bndregs = get_xsave_field_ptr(XFEATURE_MASK_BNDREGS); + bndregs = get_xsave_field_ptr(XFEATURE_BNDREGS); if (!bndregs) { err = -EINVAL; goto err_out; @@ -190,7 +190,7 @@ static __user void *mpx_get_bounds_dir(void) * The bounds directory pointer is stored in a register * only accessible if we first do an xsave. */ - bndcsr = get_xsave_field_ptr(XFEATURE_MASK_BNDCSR); + bndcsr = get_xsave_field_ptr(XFEATURE_BNDCSR); if (!bndcsr) return MPX_INVALID_BOUNDS_DIR; @@ -376,7 +376,7 @@ static int do_mpx_bt_fault(void) const struct mpx_bndcsr *bndcsr; struct mm_struct *mm = current->mm; - bndcsr = get_xsave_field_ptr(XFEATURE_MASK_BNDCSR); + bndcsr = get_xsave_field_ptr(XFEATURE_BNDCSR); if (!bndcsr) return -EINVAL; /* From patchwork Wed Nov 7 19:48:49 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672973 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E18E313AD for ; Wed, 7 Nov 2018 19:50:55 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D45782CFCF for ; Wed, 7 Nov 2018 19:50:55 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id C89FE2CFDC; Wed, 7 Nov 2018 19:50:55 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7DFAA2CFD1 for ; Wed, 7 Nov 2018 19:50:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727003AbeKHFWl (ORCPT ); Thu, 8 Nov 2018 00:22:41 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41921 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727590AbeKHFVP (ORCPT ); Thu, 8 Nov 2018 00:21:15 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTpI-00070Q-9L; Wed, 07 Nov 2018 20:49:20 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 14/23] x86/pkeys: Make init_pkru_value static Date: Wed, 7 Nov 2018 20:48:49 +0100 Message-Id: <20181107194858.9380-15-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The variable init_pkru_value isn't used outside of this file. Make init_pkru_value static. Acked-by: Dave Hansen Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/mm/pkeys.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c index 0af3ece18f113..05bb9a44eb1c3 100644 --- a/arch/x86/mm/pkeys.c +++ b/arch/x86/mm/pkeys.c @@ -126,6 +126,7 @@ int __arch_override_mprotect_pkey(struct vm_area_struct *vma, int prot, int pkey * in the process's lifetime will not accidentally get access * to data which is pkey-protected later on. */ +static u32 init_pkru_value = PKRU_AD_KEY( 1) | PKRU_AD_KEY( 2) | PKRU_AD_KEY( 3) | PKRU_AD_KEY( 4) | PKRU_AD_KEY( 5) | PKRU_AD_KEY( 6) | PKRU_AD_KEY( 7) | PKRU_AD_KEY( 8) | PKRU_AD_KEY( 9) | From patchwork Wed Nov 7 19:48:50 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672969 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 39B9013AD for ; Wed, 7 Nov 2018 19:50:47 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 2C3122CFE1 for ; Wed, 7 Nov 2018 19:50:47 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 208842CFB4; Wed, 7 Nov 2018 19:50:47 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id ABE112CFDD for ; Wed, 7 Nov 2018 19:50:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726649AbeKHFWa (ORCPT ); Thu, 8 Nov 2018 00:22:30 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41933 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727668AbeKHFVQ (ORCPT ); Thu, 8 Nov 2018 00:21:16 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTpJ-00070Q-BI; Wed, 07 Nov 2018 20:49:21 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 15/23] x86/fpu: Only write PKRU if it is different from current Date: Wed, 7 Nov 2018 20:48:50 +0100 Message-Id: <20181107194858.9380-16-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Dave Hansen says that the `wrpkru' is more expensive than `rdpkru'. It has a higher cycle cost and it's also practically a (light) speculation barrier. As an optimisation read the current PKRU value and only write the new one if it is different. Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/include/asm/special_insns.h | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h index 43c029cdc3fe8..c2ccf71b22dd6 100644 --- a/arch/x86/include/asm/special_insns.h +++ b/arch/x86/include/asm/special_insns.h @@ -107,7 +107,7 @@ static inline u32 __read_pkru(void) return pkru; } -static inline void __write_pkru(u32 pkru) +static inline void __write_pkru_insn(u32 pkru) { u32 ecx = 0, edx = 0; @@ -118,6 +118,17 @@ static inline void __write_pkru(u32 pkru) asm volatile(".byte 0x0f,0x01,0xef\n\t" : : "a" (pkru), "c"(ecx), "d"(edx)); } + +static inline void __write_pkru(u32 pkru) +{ + /* + * Writting PKRU is expensive. Only write the PKRU value if it is + * different from the current one. + */ + if (pkru == __read_pkru()) + return; + __write_pkru_insn(pkru); +} #else static inline u32 __read_pkru(void) { From patchwork Wed Nov 7 19:48:51 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672963 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8899515A6 for ; Wed, 7 Nov 2018 19:50:31 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7C3282CFB6 for ; Wed, 7 Nov 2018 19:50:31 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 796EF2CFC0; Wed, 7 Nov 2018 19:50:31 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 26EA22CFBE for ; Wed, 7 Nov 2018 19:50:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727817AbeKHFVS (ORCPT ); Thu, 8 Nov 2018 00:21:18 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41941 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727694AbeKHFVR (ORCPT ); Thu, 8 Nov 2018 00:21:17 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTpK-00070Q-Gd; Wed, 07 Nov 2018 20:49:23 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 16/23] x86/pkeys: Don't check if PKRU is zero before writting it Date: Wed, 7 Nov 2018 20:48:51 +0100 Message-Id: <20181107194858.9380-17-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP write_pkru() checks if the current value is the same as the expected value. So instead just checking if the current and new value is zero (and skip the write in such a case) we can benefit from that. Remove the zero check of PKRU, write_pkru() provides a similar check. Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/mm/pkeys.c | 7 ------- 1 file changed, 7 deletions(-) diff --git a/arch/x86/mm/pkeys.c b/arch/x86/mm/pkeys.c index 05bb9a44eb1c3..50f65fc1b9a3f 100644 --- a/arch/x86/mm/pkeys.c +++ b/arch/x86/mm/pkeys.c @@ -142,13 +142,6 @@ u32 init_pkru_value = PKRU_AD_KEY( 1) | PKRU_AD_KEY( 2) | PKRU_AD_KEY( 3) | void copy_init_pkru_to_fpregs(void) { u32 init_pkru_value_snapshot = READ_ONCE(init_pkru_value); - /* - * Any write to PKRU takes it out of the XSAVE 'init - * state' which increases context switch cost. Avoid - * writing 0 when PKRU was already 0. - */ - if (!init_pkru_value_snapshot && !read_pkru()) - return; /* * Override the PKRU state that came from 'init_fpstate' * with the baseline from the process. From patchwork Wed Nov 7 19:48:52 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672965 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 29A2413AD for ; Wed, 7 Nov 2018 19:50:34 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 192D82CF7B for ; Wed, 7 Nov 2018 19:50:34 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 0D7022CFC2; Wed, 7 Nov 2018 19:50:34 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9C1F12CF9E for ; Wed, 7 Nov 2018 19:50:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727795AbeKHFVS (ORCPT ); Thu, 8 Nov 2018 00:21:18 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41948 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727579AbeKHFVS (ORCPT ); Thu, 8 Nov 2018 00:21:18 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTpL-00070Q-QA; Wed, 07 Nov 2018 20:49:24 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 17/23] x86/fpu: Eager switch PKRU state Date: Wed, 7 Nov 2018 20:48:52 +0100 Message-Id: <20181107194858.9380-18-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Rik van Riel While most of a task's FPU state is only needed in user space, the protection keys need to be in place immediately after a context switch. The reason is that any access to userspace memory while running in kernel mode also need to abide by the memory permissions specified in the protection keys. The "eager switch" is a preparation for loading the FPU state on return to userland. Instead of decoupling PKRU state from xstate I update PKRU within xstate on write operations by the kernel. The read/write_pkru() is moved to another header file so it can easily accessed from pgtable.h and fpu/internal.h. Signed-off-by: Rik van Riel [bigeasy: save pkru to xstate, no cache] Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/include/asm/fpu/internal.h | 13 +++++++++++-- arch/x86/include/asm/fpu/xstate.h | 2 ++ arch/x86/kernel/fpu/xstate.c | 2 +- 3 files changed, 14 insertions(+), 3 deletions(-) diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 260cd4f4ba2bb..ed65e0642a1e1 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -561,8 +561,17 @@ switch_fpu_prepare(struct fpu *old_fpu, int cpu) */ static inline void switch_fpu_finish(struct fpu *new_fpu, int cpu) { - if (static_cpu_has(X86_FEATURE_FPU)) - __fpregs_load_activate(new_fpu, cpu); + if (!static_cpu_has(X86_FEATURE_FPU)) + return; + + __fpregs_load_activate(new_fpu, cpu); + + if (cpu_feature_enabled(X86_FEATURE_OSPKE)) { + struct pkru_state *pk; + + pk = __raw_xsave_addr(&new_fpu->state.xsave, XFEATURE_PKRU); + __write_pkru(pk->pkru); + } } /* diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h index fbe41f808e5d8..dd138f5eb5c66 100644 --- a/arch/x86/include/asm/fpu/xstate.h +++ b/arch/x86/include/asm/fpu/xstate.h @@ -5,6 +5,7 @@ #include #include #include +#include /* Bit 63 of XCR0 is reserved for future expansion */ #define XFEATURE_MASK_EXTEND (~(XFEATURE_MASK_FPSSE | (1ULL << 63))) @@ -47,6 +48,7 @@ extern void __init update_regset_xstate_info(unsigned int size, void fpu__xstate_clear_all_cpu_caps(void); void *get_xsave_addr(struct xregs_state *xsave, int xfeature_nr); +void *__raw_xsave_addr(struct xregs_state *xsave, int feature_nr); const void *get_xsave_field_ptr(int xfeature_nr); int using_compacted_format(void); int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int offset, unsigned int size); diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 375226055a413..5b33985d9f475 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -811,7 +811,7 @@ void fpu__resume_cpu(void) * * Note: does not work for compacted buffers. */ -static void *__raw_xsave_addr(struct xregs_state *xsave, int xfeature_nr) +void *__raw_xsave_addr(struct xregs_state *xsave, int xfeature_nr) { if (!xfeature_enabled(xfeature_nr)) { WARN_ON_FPU(1); From patchwork Wed Nov 7 19:48:53 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672961 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 9C7A315A6 for ; Wed, 7 Nov 2018 19:50:23 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 904C02C888 for ; Wed, 7 Nov 2018 19:50:23 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 83E5D2CFBD; Wed, 7 Nov 2018 19:50:23 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 21E992CF8A for ; Wed, 7 Nov 2018 19:50:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727962AbeKHFVU (ORCPT ); Thu, 8 Nov 2018 00:21:20 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41956 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727148AbeKHFVT (ORCPT ); Thu, 8 Nov 2018 00:21:19 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTpM-00070Q-Ja; Wed, 07 Nov 2018 20:49:24 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 18/23] x86/entry: Add TIF_NEED_FPU_LOAD Date: Wed, 7 Nov 2018 20:48:53 +0100 Message-Id: <20181107194858.9380-19-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Add TIF_NEED_FPU_LOAD. This is reserved for loading the FPU registers before returning to userland. This flag must not be set for systems without a FPU. If this flag is cleared, the CPU's FPU register hold the current content of current()'s FPU register. The in-memory copy (union fpregs_state) is not valid. If this flag is set, then all of CPU's FPU register may hold a random value (except for PKRU) and it is required to load the content of the FPU register on return to userland. It is introduced now, so we can add code handling it now before adding the main feature. Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/include/asm/thread_info.h | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/include/asm/thread_info.h b/arch/x86/include/asm/thread_info.h index cd6920674b905..963a39da0a95c 100644 --- a/arch/x86/include/asm/thread_info.h +++ b/arch/x86/include/asm/thread_info.h @@ -83,6 +83,7 @@ struct thread_info { #define TIF_SYSCALL_EMU 6 /* syscall emulation active */ #define TIF_SYSCALL_AUDIT 7 /* syscall auditing active */ #define TIF_SECCOMP 8 /* secure computing */ +#define TIF_NEED_FPU_LOAD 10 /* load FPU on return to userspace */ #define TIF_USER_RETURN_NOTIFY 11 /* notify kernel of userspace return */ #define TIF_UPROBE 12 /* breakpointed or singlestepping */ #define TIF_PATCH_PENDING 13 /* pending live patching update */ @@ -110,6 +111,7 @@ struct thread_info { #define _TIF_SYSCALL_EMU (1 << TIF_SYSCALL_EMU) #define _TIF_SYSCALL_AUDIT (1 << TIF_SYSCALL_AUDIT) #define _TIF_SECCOMP (1 << TIF_SECCOMP) +#define _TIF_NEED_FPU_LOAD (1 << TIF_NEED_FPU_LOAD) #define _TIF_USER_RETURN_NOTIFY (1 << TIF_USER_RETURN_NOTIFY) #define _TIF_UPROBE (1 << TIF_UPROBE) #define _TIF_PATCH_PENDING (1 << TIF_PATCH_PENDING) From patchwork Wed Nov 7 19:48:54 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672959 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 0F32613AD for ; Wed, 7 Nov 2018 19:50:19 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 001E92CF9B for ; Wed, 7 Nov 2018 19:50:18 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E855E2CFB6; Wed, 7 Nov 2018 19:50:18 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4A25E2CFBD for ; Wed, 7 Nov 2018 19:50:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728033AbeKHFVW (ORCPT ); Thu, 8 Nov 2018 00:21:22 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41964 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727696AbeKHFVV (ORCPT ); Thu, 8 Nov 2018 00:21:21 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTpN-00070Q-Jo; Wed, 07 Nov 2018 20:49:25 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 19/23] x86/fpu: Always store the registers in copy_fpstate_to_sigframe() Date: Wed, 7 Nov 2018 20:48:54 +0100 Message-Id: <20181107194858.9380-20-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Rik van Riel copy_fpstate_to_sigframe() stores the registers directly to user space. This is okay because the FPU register are valid and saving it directly avoids saving it into kernel memory and making a copy. However… We can't keep doing this if we are going to restore the FPU registers on the return to userland. It is possible that the FPU registers will be invalidated in the middle of the save operation and this should be done with disabled preemption / BH. Save the FPU registers to task's FPU struct and copy them to the user memory. later on. This code is extracted from an earlier version of the patchset while there still was lazy-FPU on x86. Signed-off-by: Rik van Riel Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/include/asm/fpu/internal.h | 45 ----------------------------- arch/x86/kernel/fpu/signal.c | 30 +++++++------------ 2 files changed, 11 insertions(+), 64 deletions(-) diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index ed65e0642a1e1..9e213a6703c84 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -123,22 +123,6 @@ extern void fpstate_sanitize_xstate(struct fpu *fpu); _ASM_EXTABLE_HANDLE(1b, 2b, ex_handler_fprestore) \ : output : input) -static inline int copy_fregs_to_user(struct fregs_state __user *fx) -{ - return user_insn(fnsave %[fx]; fwait, [fx] "=m" (*fx), "m" (*fx)); -} - -static inline int copy_fxregs_to_user(struct fxregs_state __user *fx) -{ - if (IS_ENABLED(CONFIG_X86_32)) - return user_insn(fxsave %[fx], [fx] "=m" (*fx), "m" (*fx)); - else if (IS_ENABLED(CONFIG_AS_FXSAVEQ)) - return user_insn(fxsaveq %[fx], [fx] "=m" (*fx), "m" (*fx)); - - /* See comment in copy_fxregs_to_kernel() below. */ - return user_insn(rex64/fxsave (%[fx]), "=m" (*fx), [fx] "R" (fx)); -} - static inline void copy_kernel_to_fxregs(struct fxregs_state *fx) { if (IS_ENABLED(CONFIG_X86_32)) { @@ -349,35 +333,6 @@ static inline void copy_kernel_to_xregs(struct xregs_state *xstate, u64 mask) XSTATE_XRESTORE(xstate, lmask, hmask); } -/* - * Save xstate to user space xsave area. - * - * We don't use modified optimization because xrstor/xrstors might track - * a different application. - * - * We don't use compacted format xsave area for - * backward compatibility for old applications which don't understand - * compacted format of xsave area. - */ -static inline int copy_xregs_to_user(struct xregs_state __user *buf) -{ - int err; - - /* - * Clear the xsave header first, so that reserved fields are - * initialized to zero. - */ - err = __clear_user(&buf->header, sizeof(buf->header)); - if (unlikely(err)) - return -EFAULT; - - stac(); - XSTATE_OP(XSAVE, buf, -1, -1, err); - clac(); - - return err; -} - /* * Restore xstate from user space xsave area. */ diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index f61f4d804537a..254a8dff9cd82 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -118,22 +118,6 @@ static inline int save_xstate_epilog(void __user *buf, int ia32_frame) return err; } -static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf) -{ - int err; - - if (use_xsave()) - err = copy_xregs_to_user(buf); - else if (use_fxsr()) - err = copy_fxregs_to_user((struct fxregs_state __user *) buf); - else - err = copy_fregs_to_user((struct fregs_state __user *) buf); - - if (unlikely(err) && __clear_user(buf, fpu_user_xstate_size)) - err = -EFAULT; - return err; -} - /* * Save the fpu, extended register state to the user signal frame. * @@ -157,6 +141,7 @@ static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf) int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size) { struct fpu *fpu = ¤t->thread.fpu; + struct xregs_state *xsave = &fpu->state.xsave; struct task_struct *tsk = current; int ia32_fxstate = (buf != buf_fx); @@ -171,12 +156,19 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size) sizeof(struct user_i387_ia32_struct), NULL, (struct _fpstate_32 __user *) buf) ? -1 : 1; - /* Save the live register state to the user directly. */ - if (copy_fpregs_to_sigframe(buf_fx)) - return -1; /* Update the thread's fxstate to save the fsave header. */ if (ia32_fxstate) copy_fxregs_to_kernel(fpu); + else + copy_fpregs_to_fpstate(fpu); + + if (using_compacted_format()) { + copy_xstate_to_user(buf_fx, xsave, 0, size); + } else { + fpstate_sanitize_xstate(fpu); + if (__copy_to_user(buf_fx, xsave, fpu_user_xstate_size)) + return -1; + } /* Save the fsave header for the 32-bit frames. */ if ((ia32_fxstate || !use_fxsr()) && save_fsave_header(tsk, buf)) From patchwork Wed Nov 7 19:48:55 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672957 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id F310615A6 for ; Wed, 7 Nov 2018 19:50:14 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id D996D2CFBD for ; Wed, 7 Nov 2018 19:50:14 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CDE182CF76; Wed, 7 Nov 2018 19:50:14 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6E6082CF76 for ; Wed, 7 Nov 2018 19:50:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728100AbeKHFVW (ORCPT ); Thu, 8 Nov 2018 00:21:22 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41970 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727454AbeKHFVW (ORCPT ); Thu, 8 Nov 2018 00:21:22 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTpO-00070Q-QI; Wed, 07 Nov 2018 20:49:27 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 20/23] x86/fpu: Prepare copy_fpstate_to_sigframe() for TIF_NEED_FPU_LOAD Date: Wed, 7 Nov 2018 20:48:55 +0100 Message-Id: <20181107194858.9380-21-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Rik van Riel The FPU registers need only to be saved if TIF_NEED_FPU_LOAD is not set. Otherwise this has been already done and can be skipped. Signed-off-by: Rik van Riel Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/kernel/fpu/signal.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-) diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 254a8dff9cd82..179e2b19976ad 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -156,11 +156,20 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size) sizeof(struct user_i387_ia32_struct), NULL, (struct _fpstate_32 __user *) buf) ? -1 : 1; - /* Update the thread's fxstate to save the fsave header. */ - if (ia32_fxstate) - copy_fxregs_to_kernel(fpu); - else - copy_fpregs_to_fpstate(fpu); + __fpregs_changes_begin(); + /* + * If we do not need to load the FPU registers at return to userspace + * then the CPU has the current state and we need to save it. Otherwise + * it is already done and we can skip it. + */ + if (!test_thread_flag(TIF_NEED_FPU_LOAD)) { + /* Update the thread's fxstate to save the fsave header. */ + if (ia32_fxstate) + copy_fxregs_to_kernel(fpu); + else + copy_fpregs_to_fpstate(fpu); + } + __fpregs_changes_end(); if (using_compacted_format()) { copy_xstate_to_user(buf_fx, xsave, 0, size); From patchwork Wed Nov 7 19:48:56 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672955 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7405915A6 for ; Wed, 7 Nov 2018 19:50:04 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 655B12CF65 for ; Wed, 7 Nov 2018 19:50:04 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 584902CF73; Wed, 7 Nov 2018 19:50:04 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 0662B2CF65 for ; Wed, 7 Nov 2018 19:50:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726444AbeKHFVr (ORCPT ); Thu, 8 Nov 2018 00:21:47 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41974 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727694AbeKHFVW (ORCPT ); Thu, 8 Nov 2018 00:21:22 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTpP-00070Q-TO; Wed, 07 Nov 2018 20:49:28 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 21/23] x86/fpu: Update xstate's PKRU value on write_pkru() Date: Wed, 7 Nov 2018 20:48:56 +0100 Message-Id: <20181107194858.9380-22-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP During the context switch the xstate is loaded which also includes the PKRU value. If xstate is restored on return to userland it is required that the PKRU value in xstate is the same as the one in the CPU. Save the PKRU in xstate during modification. Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/include/asm/pgtable.h | 19 +++++++++++++++++-- 1 file changed, 17 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 40616e8052924..45ca1c7802812 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -23,6 +23,8 @@ #ifndef __ASSEMBLY__ #include +#include +#include extern pgd_t early_top_pgt[PTRS_PER_PGD]; int __init __early_make_pgtable(unsigned long address, pmdval_t pmd); @@ -133,8 +135,21 @@ static inline u32 read_pkru(void) static inline void write_pkru(u32 pkru) { - if (boot_cpu_has(X86_FEATURE_OSPKE)) - __write_pkru(pkru); + struct pkru_state *pk; + + if (!boot_cpu_has(X86_FEATURE_OSPKE)) + return; + + pk = __raw_xsave_addr(¤t->thread.fpu.state.xsave, XFEATURE_PKRU); + /* + * The PKRU value in xstate needs to be in sync with the value that is + * written to the CPU. The FPU restore on return to userland would + * otherwise load the previous value again. + */ + __fpregs_changes_begin(); + pk->pkru = pkru; + __write_pkru(pkru); + __fpregs_changes_end(); } static inline int pte_young(pte_t pte) From patchwork Wed Nov 7 19:48:57 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672953 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 7A34D13AD for ; Wed, 7 Nov 2018 19:49:57 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6B47D2CF65 for ; Wed, 7 Nov 2018 19:49:57 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 5EFB32CF73; Wed, 7 Nov 2018 19:49:57 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id CD2BD2CF65 for ; Wed, 7 Nov 2018 19:49:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727719AbeKHFVZ (ORCPT ); Thu, 8 Nov 2018 00:21:25 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41990 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727454AbeKHFVY (ORCPT ); Thu, 8 Nov 2018 00:21:24 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTpR-00070Q-7K; Wed, 07 Nov 2018 20:49:29 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 22/23] x86/fpu: Don't restore the FPU state directly from userland in __fpu__restore_sig() Date: Wed, 7 Nov 2018 20:48:57 +0100 Message-Id: <20181107194858.9380-23-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP __fpu__restore_sig() restores the CPU's FPU state directly from userland. If we restore registers on return to userland then we can't load them directly from userland because a context switch/BH could destroy them. Restore the FPU registers after they have been copied from userland. __fpregs_changes_begin() ensures that they are not modified while beeing worked on. TIF_NEED_FPU_LOAD is clreared we want to keep our state, not the saved state. Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/include/asm/fpu/internal.h | 34 ----------------------------- arch/x86/kernel/fpu/signal.c | 33 ++++++++++++++++++---------- 2 files changed, 22 insertions(+), 45 deletions(-) diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 9e213a6703c84..5e86ff60a3a5c 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -137,28 +137,11 @@ static inline void copy_kernel_to_fxregs(struct fxregs_state *fx) } } -static inline int copy_user_to_fxregs(struct fxregs_state __user *fx) -{ - if (IS_ENABLED(CONFIG_X86_32)) - return user_insn(fxrstor %[fx], "=m" (*fx), [fx] "m" (*fx)); - else if (IS_ENABLED(CONFIG_AS_FXSAVEQ)) - return user_insn(fxrstorq %[fx], "=m" (*fx), [fx] "m" (*fx)); - - /* See comment in copy_fxregs_to_kernel() below. */ - return user_insn(rex64/fxrstor (%[fx]), "=m" (*fx), [fx] "R" (fx), - "m" (*fx)); -} - static inline void copy_kernel_to_fregs(struct fregs_state *fx) { kernel_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx)); } -static inline int copy_user_to_fregs(struct fregs_state __user *fx) -{ - return user_insn(frstor %[fx], "=m" (*fx), [fx] "m" (*fx)); -} - static inline void copy_fxregs_to_kernel(struct fpu *fpu) { if (IS_ENABLED(CONFIG_X86_32)) @@ -333,23 +316,6 @@ static inline void copy_kernel_to_xregs(struct xregs_state *xstate, u64 mask) XSTATE_XRESTORE(xstate, lmask, hmask); } -/* - * Restore xstate from user space xsave area. - */ -static inline int copy_user_to_xregs(struct xregs_state __user *buf, u64 mask) -{ - struct xregs_state *xstate = ((__force struct xregs_state *)buf); - u32 lmask = mask; - u32 hmask = mask >> 32; - int err; - - stac(); - XSTATE_OP(XRSTOR, xstate, lmask, hmask, err); - clac(); - - return err; -} - /* * These must be called with preempt disabled. Returns * 'true' if the FPU state is still intact and we can diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 179e2b19976ad..9720529859483 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -228,23 +228,30 @@ sanitize_restored_xstate(union fpregs_state *state, /* * Restore the extended state if present. Otherwise, restore the FP/SSE state. */ -static inline int copy_user_to_fpregs_zeroing(void __user *buf, u64 xbv, int fx_only) +static void copy_to_fpregs_zeroing(struct fpu *fpu, u64 xbv, int fx_only) { + __fpregs_changes_begin(); if (use_xsave()) { - if ((unsigned long)buf % 64 || fx_only) { + if (fx_only) { u64 init_bv = xfeatures_mask & ~XFEATURE_MASK_FPSSE; + copy_kernel_to_xregs(&init_fpstate.xsave, init_bv); - return copy_user_to_fxregs(buf); + copy_kernel_to_fxregs(&fpu->state.fxsave); } else { u64 init_bv = xfeatures_mask & ~xbv; + if (unlikely(init_bv)) copy_kernel_to_xregs(&init_fpstate.xsave, init_bv); - return copy_user_to_xregs(buf, xbv); + copy_kernel_to_xregs(&fpu->state.xsave, xbv); } } else if (use_fxsr()) { - return copy_user_to_fxregs(buf); - } else - return copy_user_to_fregs(buf); + copy_kernel_to_fxregs(&fpu->state.fxsave); + } else { + copy_kernel_to_fregs(&fpu->state.fsave); + } + clear_thread_flag(TIF_NEED_FPU_LOAD); + fpregs_activate(fpu); + __fpregs_changes_end(); } static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) @@ -255,6 +262,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) int state_size = fpu_kernel_xstate_size; u64 xfeatures = 0; int fx_only = 0; + int err = 0; ia32_fxstate &= (IS_ENABLED(CONFIG_X86_32) || IS_ENABLED(CONFIG_IA32_EMULATION)); @@ -298,7 +306,6 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) union fpregs_state *state; void *tmp; struct user_i387_ia32_struct env; - int err = 0; tmp = kmalloc(sizeof(*state) + fpu_kernel_xstate_size + 64, GFP_KERNEL); if (!tmp) @@ -327,12 +334,16 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) } else { /* * For 64-bit frames and 32-bit fsave frames, restore the user - * state to the registers directly (with exceptions handled). + * state from a copy in thread's fpu state. */ - if (copy_user_to_fpregs_zeroing(buf_fx, xfeatures, fx_only)) { + err = __copy_from_user(&fpu->state.xsave, buf_fx, state_size); + if (err) { fpu__clear(fpu); - return -1; + return -EFAULT; } + if ((unsigned long)buf_fx % 64) + fx_only = 1; + copy_to_fpregs_zeroing(fpu, xfeatures, fx_only); } return 0; From patchwork Wed Nov 7 19:48:58 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sebastian Andrzej Siewior X-Patchwork-Id: 10672951 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id F041515A6 for ; Wed, 7 Nov 2018 19:49:43 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DF5E52CF64 for ; Wed, 7 Nov 2018 19:49:43 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D34B92CF69; Wed, 7 Nov 2018 19:49:43 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id A1FF62CF64 for ; Wed, 7 Nov 2018 19:49:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727246AbeKHFVa (ORCPT ); Thu, 8 Nov 2018 00:21:30 -0500 Received: from Galois.linutronix.de ([146.0.238.70]:41996 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727454AbeKHFVa (ORCPT ); Thu, 8 Nov 2018 00:21:30 -0500 Received: from localhost ([127.0.0.1] helo=bazinga.breakpoint.cc) by Galois.linutronix.de with esmtp (Exim 4.80) (envelope-from ) id 1gKTpT-00070Q-Ax; Wed, 07 Nov 2018 20:49:31 +0100 From: Sebastian Andrzej Siewior To: linux-kernel@vger.kernel.org Cc: x86@kernel.org, Andy Lutomirski , Paolo Bonzini , =?utf-8?b?UmFkaW0gS3LEjW3DocWZ?= , kvm@vger.kernel.org, "Jason A. Donenfeld" , Rik van Riel , Dave Hansen , Sebastian Andrzej Siewior Subject: [PATCH 23/23] x86/fpu: Defer FPU state load until return to userspace Date: Wed, 7 Nov 2018 20:48:58 +0100 Message-Id: <20181107194858.9380-24-bigeasy@linutronix.de> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20181107194858.9380-1-bigeasy@linutronix.de> References: <20181107194858.9380-1-bigeasy@linutronix.de> MIME-Version: 1.0 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Rik van Riel Defer loading of FPU state until return to userspace. This gives the kernel the potential to skip loading FPU state for tasks that stay in kernel mode, or for tasks that end up with repeated invocations of kernel_fpu_begin() & kernel_fpu_end(). The __fpregs_changes_{begin|end}() section ensures that the register remain unchanged. Otherwise a context switch or a BH could save the registers to its FPU context and processor's FPU register would became random if beeing modified at the same time. KVM swaps the host/guest register on entry/exit path. I kept the flow as is. First it ensures that the registers are loaded and then saves the current (host) state before it loads the guest's register. The swap is done at the very end with disabled interrupts so it should not change anymore before theg guest is entered. The read/save version seems to be cheaper compared to memcpy() in a micro benchmark. Each thread gets TIF_NEED_FPU_LOAD set as part of fork() / fpu__copy(). For kernel threads, this flag gets never cleared which avoids saving / restoring the FPU state for kernel threads and during in-kernel usage of the FPU register. This should restore the performance regression which was introduced after the removal of the ->initialized field in struct fpu. Signed-off-by: Rik van Riel Signed-off-by: Sebastian Andrzej Siewior --- arch/x86/entry/common.c | 8 +++ arch/x86/include/asm/fpu/api.h | 14 +++++ arch/x86/include/asm/fpu/internal.h | 31 +++++---- arch/x86/include/asm/trace/fpu.h | 5 +- arch/x86/kernel/fpu/core.c | 97 +++++++++++++++++++++++------ arch/x86/kernel/fpu/signal.c | 49 ++++++++------- arch/x86/kernel/process.c | 2 +- arch/x86/kernel/process_32.c | 5 +- arch/x86/kernel/process_64.c | 5 +- arch/x86/kvm/x86.c | 19 ++++-- 10 files changed, 172 insertions(+), 63 deletions(-) diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c index 3b2490b819181..e46fe9aa2934a 100644 --- a/arch/x86/entry/common.c +++ b/arch/x86/entry/common.c @@ -31,6 +31,7 @@ #include #include #include +#include #define CREATE_TRACE_POINTS #include @@ -196,6 +197,13 @@ __visible inline void prepare_exit_to_usermode(struct pt_regs *regs) if (unlikely(cached_flags & EXIT_TO_USERMODE_LOOP_FLAGS)) exit_to_usermode_loop(regs, cached_flags); + /* Reload ti->flags; we may have rescheduled above. */ + cached_flags = READ_ONCE(ti->flags); + + fpregs_assert_state_consistent(); + if (unlikely(cached_flags & _TIF_NEED_FPU_LOAD)) + switch_fpu_return(); + #ifdef CONFIG_COMPAT /* * Compat syscalls set TS_COMPAT. Make sure we clear it before diff --git a/arch/x86/include/asm/fpu/api.h b/arch/x86/include/asm/fpu/api.h index 8c03b42416656..d10b60d80d35a 100644 --- a/arch/x86/include/asm/fpu/api.h +++ b/arch/x86/include/asm/fpu/api.h @@ -27,17 +27,31 @@ extern void __kernel_fpu_end(void); extern void kernel_fpu_begin(void); extern void kernel_fpu_end(void); extern bool irq_fpu_usable(void); +extern void fpregs_mark_activate(void); static inline void __fpregs_changes_begin(void) { preempt_disable(); + local_bh_disable(); } static inline void __fpregs_changes_end(void) { + local_bh_enable(); preempt_enable(); } +#ifdef CONFIG_X86_DEBUG_FPU +extern void fpregs_assert_state_consistent(void); +#else +static inline void fpregs_assert_state_consistent(void) { } +#endif + +/* + * Load the task FPU state before returning to userspace. + */ +extern void switch_fpu_return(void); + /* * Query the presence of one or more xfeatures. Works on any legacy CPU as well. * diff --git a/arch/x86/include/asm/fpu/internal.h b/arch/x86/include/asm/fpu/internal.h index 5e86ff60a3a5c..0406f0987697f 100644 --- a/arch/x86/include/asm/fpu/internal.h +++ b/arch/x86/include/asm/fpu/internal.h @@ -29,7 +29,7 @@ extern void fpu__prepare_write(struct fpu *fpu); extern void fpu__save(struct fpu *fpu); extern int fpu__restore_sig(void __user *buf, int ia32_frame); extern void fpu__drop(struct fpu *fpu); -extern int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu); +extern int fpu__copy(struct task_struct *dst, struct task_struct *src); extern void fpu__clear(struct fpu *fpu); extern int fpu__exception_code(struct fpu *fpu, int trap_nr); extern int dump_fpu(struct pt_regs *ptregs, struct user_i387_struct *fpstate); @@ -436,15 +436,20 @@ static inline void fpregs_activate(struct fpu *fpu) /* * Load the FPU state for the current task. Call with preemption disabled. */ -static inline void __fpregs_load_activate(struct fpu *fpu, int cpu) +static inline void __fpregs_load_activate(void) { + struct fpu *fpu = ¤t->thread.fpu; + int cpu = smp_processor_id(); + int kthread = current->mm == NULL; + + if (kthread) + return; if (!fpregs_state_valid(fpu, cpu)) { - if (current->mm) - copy_kernel_to_fpregs(&fpu->state); - else - copy_kernel_to_fpregs(&init_fpstate); + copy_kernel_to_fpregs(&fpu->state); + fpregs_activate(fpu); + fpu->last_cpu = cpu; } - fpregs_activate(fpu); + clear_thread_flag(TIF_NEED_FPU_LOAD); } /* @@ -455,8 +460,8 @@ static inline void __fpregs_load_activate(struct fpu *fpu, int cpu) * - switch_fpu_prepare() saves the old state. * This is done within the context of the old process. * - * - switch_fpu_finish() restores the new state as - * necessary. + * - switch_fpu_finish() sets TIF_NEED_FPU_LOAD; the floating point state + * will get loaded on return to userspace, or when the kernel needs it. */ static inline void switch_fpu_prepare(struct fpu *old_fpu, int cpu) @@ -477,15 +482,15 @@ switch_fpu_prepare(struct fpu *old_fpu, int cpu) */ /* - * Set up the userspace FPU context for the new task, if the task - * has used the FPU. + * Load PKRU from the FPU context if available. Delay loading the loading of the + * complete FPU state until the return to userland. */ -static inline void switch_fpu_finish(struct fpu *new_fpu, int cpu) +static inline void switch_fpu_finish(struct fpu *new_fpu) { if (!static_cpu_has(X86_FEATURE_FPU)) return; - __fpregs_load_activate(new_fpu, cpu); + set_thread_flag(TIF_NEED_FPU_LOAD); if (cpu_feature_enabled(X86_FEATURE_OSPKE)) { struct pkru_state *pk; diff --git a/arch/x86/include/asm/trace/fpu.h b/arch/x86/include/asm/trace/fpu.h index bd65f6ba950f8..91a1422091ceb 100644 --- a/arch/x86/include/asm/trace/fpu.h +++ b/arch/x86/include/asm/trace/fpu.h @@ -13,19 +13,22 @@ DECLARE_EVENT_CLASS(x86_fpu, TP_STRUCT__entry( __field(struct fpu *, fpu) + __field(bool, load_fpu) __field(u64, xfeatures) __field(u64, xcomp_bv) ), TP_fast_assign( __entry->fpu = fpu; + __entry->load_fpu = test_thread_flag(TIF_NEED_FPU_LOAD); if (boot_cpu_has(X86_FEATURE_OSXSAVE)) { __entry->xfeatures = fpu->state.xsave.header.xfeatures; __entry->xcomp_bv = fpu->state.xsave.header.xcomp_bv; } ), - TP_printk("x86/fpu: %p xfeatures: %llx xcomp_bv: %llx", + TP_printk("x86/fpu: %p load: %d xfeatures: %llx xcomp_bv: %llx", __entry->fpu, + __entry->load_fpu, __entry->xfeatures, __entry->xcomp_bv ) diff --git a/arch/x86/kernel/fpu/core.c b/arch/x86/kernel/fpu/core.c index 02bbd40fe1e95..85746819deed2 100644 --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -101,16 +101,20 @@ void __kernel_fpu_begin(void) kernel_fpu_disable(); - copy_fpregs_to_fpstate(fpu); + __cpu_invalidate_fpregs_state(); + if (!test_thread_flag(TIF_NEED_FPU_LOAD)) { + set_thread_flag(TIF_NEED_FPU_LOAD); + /* + * Ignore return value -- we don't care if reg state + * is clobbered. + */ + copy_fpregs_to_fpstate(fpu); + } } EXPORT_SYMBOL(__kernel_fpu_begin); void __kernel_fpu_end(void) { - struct fpu *fpu = ¤t->thread.fpu; - - copy_kernel_to_fpregs(&fpu->state); - kernel_fpu_enable(); } EXPORT_SYMBOL(__kernel_fpu_end); @@ -138,14 +142,16 @@ void fpu__save(struct fpu *fpu) { WARN_ON_FPU(fpu != ¤t->thread.fpu); - preempt_disable(); + __fpregs_changes_begin(); trace_x86_fpu_before_save(fpu); - if (!copy_fpregs_to_fpstate(fpu)) { - copy_kernel_to_fpregs(&fpu->state); + if (!test_thread_flag(TIF_NEED_FPU_LOAD)) { + if (!copy_fpregs_to_fpstate(fpu)) { + copy_kernel_to_fpregs(&fpu->state); + } } trace_x86_fpu_after_save(fpu); - preempt_enable(); + __fpregs_changes_end(); } EXPORT_SYMBOL_GPL(fpu__save); @@ -178,8 +184,11 @@ void fpstate_init(union fpregs_state *state) } EXPORT_SYMBOL_GPL(fpstate_init); -int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu) +int fpu__copy(struct task_struct *dst, struct task_struct *src) { + struct fpu *dst_fpu = &dst->thread.fpu; + struct fpu *src_fpu = &src->thread.fpu; + dst_fpu->last_cpu = -1; if (!static_cpu_has(X86_FEATURE_FPU)) @@ -194,16 +203,23 @@ int fpu__copy(struct fpu *dst_fpu, struct fpu *src_fpu) memset(&dst_fpu->state.xsave, 0, fpu_kernel_xstate_size); /* - * Save current FPU registers directly into the child - * FPU context, without any memory-to-memory copying. + * If the FPU registers are not current just memcpy() the state. + * Otherwise save current FPU registers directly into the child's FPU + * context, without any memory-to-memory copying. * * ( The function 'fails' in the FNSAVE case, which destroys - * register contents so we have to copy them back. ) + * register contents so we have to load them back. ) */ - if (!copy_fpregs_to_fpstate(dst_fpu)) { - memcpy(&src_fpu->state, &dst_fpu->state, fpu_kernel_xstate_size); - copy_kernel_to_fpregs(&src_fpu->state); - } + __fpregs_changes_begin(); + if (test_thread_flag(TIF_NEED_FPU_LOAD)) + memcpy(&dst_fpu->state, &src_fpu->state, fpu_kernel_xstate_size); + + else if (!copy_fpregs_to_fpstate(dst_fpu)) + copy_kernel_to_fpregs(&dst_fpu->state); + + __fpregs_changes_end(); + + set_tsk_thread_flag(dst, TIF_NEED_FPU_LOAD); trace_x86_fpu_copy_src(src_fpu); trace_x86_fpu_copy_dst(dst_fpu); @@ -219,10 +235,9 @@ static void fpu__initialize(struct fpu *fpu) { WARN_ON_FPU(fpu != ¤t->thread.fpu); + set_thread_flag(TIF_NEED_FPU_LOAD); fpstate_init(&fpu->state); trace_x86_fpu_init_state(fpu); - - trace_x86_fpu_activate_state(fpu); } /* @@ -301,6 +316,8 @@ void fpu__drop(struct fpu *fpu) */ static inline void copy_init_fpstate_to_fpregs(void) { + __fpregs_changes_begin(); + if (use_xsave()) copy_kernel_to_xregs(&init_fpstate.xsave, -1); else if (static_cpu_has(X86_FEATURE_FXSR)) @@ -310,6 +327,9 @@ static inline void copy_init_fpstate_to_fpregs(void) if (boot_cpu_has(X86_FEATURE_OSPKE)) copy_init_pkru_to_fpregs(); + + fpregs_mark_activate(); + __fpregs_changes_end(); } /* @@ -332,6 +352,45 @@ void fpu__clear(struct fpu *fpu) copy_init_fpstate_to_fpregs(); } +/* + * Load FPU context before returning to userspace. + */ +void switch_fpu_return(void) +{ + if (!static_cpu_has(X86_FEATURE_FPU)) + return; + + __fpregs_load_activate(); +} +EXPORT_SYMBOL_GPL(switch_fpu_return); + +#ifdef CONFIG_X86_DEBUG_FPU +/* + * If current FPU state according to its tracking (loaded FPU ctx on this CPU) + * is not valid then we must have TIF_NEED_FPU_LOAD set so the context is loaded on + * return to userland. + */ +void fpregs_assert_state_consistent(void) +{ + struct fpu *fpu = ¤t->thread.fpu; + + if (test_thread_flag(TIF_NEED_FPU_LOAD)) + return; + WARN_ON_FPU(!fpregs_state_valid(fpu, smp_processor_id())); +} +EXPORT_SYMBOL_GPL(fpregs_assert_state_consistent); +#endif + +void fpregs_mark_activate(void) +{ + struct fpu *fpu = ¤t->thread.fpu; + + fpregs_activate(fpu); + fpu->last_cpu = smp_processor_id(); + clear_thread_flag(TIF_NEED_FPU_LOAD); +} +EXPORT_SYMBOL_GPL(fpregs_mark_activate); + /* * x87 math exception handling: */ diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index 9720529859483..9a9c379c23c35 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -251,6 +251,7 @@ static void copy_to_fpregs_zeroing(struct fpu *fpu, u64 xbv, int fx_only) } clear_thread_flag(TIF_NEED_FPU_LOAD); fpregs_activate(fpu); + fpu->last_cpu = smp_processor_id(); __fpregs_changes_end(); } @@ -262,7 +263,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) int state_size = fpu_kernel_xstate_size; u64 xfeatures = 0; int fx_only = 0; - int err = 0; + int err; ia32_fxstate &= (IS_ENABLED(CONFIG_X86_32) || IS_ENABLED(CONFIG_IA32_EMULATION)); @@ -297,40 +298,43 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) } } + /* + * The current state of the FPU registers does not matter. By setting + * TIF_NEED_FPU_LOAD unconditionally it is ensured that the our xstate + * is not modified on context switch and that the xstate is considered + * to loaded again on return to userland (overriding last_cpu avoids the + * optimisation). + */ + set_thread_flag(TIF_NEED_FPU_LOAD); + __fpu_invalidate_fpregs_state(fpu); + if (ia32_fxstate) { /* * For 32-bit frames with fxstate, copy the user state to the * thread's fpu state, reconstruct fxstate from the fsave * header. Validate and sanitize the copied state. */ - union fpregs_state *state; - void *tmp; struct user_i387_ia32_struct env; - tmp = kmalloc(sizeof(*state) + fpu_kernel_xstate_size + 64, GFP_KERNEL); - if (!tmp) - return -ENOMEM; - state = PTR_ALIGN(tmp, 64); - if (using_compacted_format()) { - err = copy_user_to_xstate(&state->xsave, buf_fx); + err = copy_user_to_xstate(&fpu->state.xsave, buf_fx); } else { - err = __copy_from_user(&state->xsave, buf_fx, state_size); + err = __copy_from_user(&fpu->state.xsave, buf_fx, state_size); if (!err && state_size > offsetof(struct xregs_state, header)) - err = validate_xstate_header(&state->xsave.header); + err = validate_xstate_header(&fpu->state.xsave.header); + } + if (err) { + err = -EINVAL; + goto out; } - if (err || __copy_from_user(&env, buf, sizeof(env))) { - err = -1; - } else { - sanitize_restored_xstate(state, &env, - xfeatures, fx_only); - copy_kernel_to_fpregs(state); + if (__copy_from_user(&env, buf, sizeof(env))) { + err = -EFAULT; + goto out; } - kfree(tmp); - return err; + sanitize_restored_xstate(&fpu->state, &env, xfeatures, fx_only); } else { /* * For 64-bit frames and 32-bit fsave frames, restore the user @@ -338,8 +342,8 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) */ err = __copy_from_user(&fpu->state.xsave, buf_fx, state_size); if (err) { - fpu__clear(fpu); - return -EFAULT; + err = EFAULT; + goto out; } if ((unsigned long)buf_fx % 64) fx_only = 1; @@ -347,6 +351,9 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) } return 0; +out: + fpu__clear(fpu); + return err; } static inline int xstate_sigframe_size(void) diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index c93fcfdf16734..cd7105fb92bfc 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -96,7 +96,7 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src) dst->thread.vm86 = NULL; #endif - return fpu__copy(&dst->thread.fpu, &src->thread.fpu); + return fpu__copy(dst, src); } /* diff --git a/arch/x86/kernel/process_32.c b/arch/x86/kernel/process_32.c index 5c99e49c0d392..5c059ecb136db 100644 --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -233,7 +233,8 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) /* never put a printk in __switch_to... printk() calls wake_up*() indirectly */ - switch_fpu_prepare(prev_fpu, cpu); + if (!test_thread_flag(TIF_NEED_FPU_LOAD)) + switch_fpu_prepare(prev_fpu, cpu); /* * Save away %gs. No need to save %fs, as it was saved on the @@ -294,7 +295,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) this_cpu_write(current_task, next_p); - switch_fpu_finish(next_fpu, cpu); + switch_fpu_finish(next_fpu); /* Load the Intel cache allocation PQR MSR. */ intel_rdt_sched_in(); diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c index 4fd0dfa5bd83e..83c3ea439190a 100644 --- a/arch/x86/kernel/process_64.c +++ b/arch/x86/kernel/process_64.c @@ -558,7 +558,8 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) WARN_ON_ONCE(IS_ENABLED(CONFIG_DEBUG_ENTRY) && this_cpu_read(irq_count) != -1); - switch_fpu_prepare(prev_fpu, cpu); + if (!test_thread_flag(TIF_NEED_FPU_LOAD)) + switch_fpu_prepare(prev_fpu, cpu); /* We must save %fs and %gs before load_TLS() because * %fs and %gs may be cleared by load_TLS(). @@ -610,7 +611,7 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) this_cpu_write(current_task, next_p); this_cpu_write(cpu_current_top_of_stack, task_top_of_stack(next_p)); - switch_fpu_finish(next_fpu, cpu); + switch_fpu_finish(next_fpu); /* Reload sp0. */ update_task_stack(next_p); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 75301b439b6e4..4cc57223893c5 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7734,6 +7734,10 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu) wait_lapic_expire(vcpu); guest_enter_irqoff(); + fpregs_assert_state_consistent(); + if (test_thread_flag(TIF_NEED_FPU_LOAD)) + switch_fpu_return(); + if (unlikely(vcpu->arch.switch_db_regs)) { set_debugreg(0, 7); set_debugreg(vcpu->arch.eff_db[0], 0); @@ -7993,22 +7997,29 @@ static int complete_emulated_mmio(struct kvm_vcpu *vcpu) /* Swap (qemu) user FPU context for the guest FPU context. */ static void kvm_load_guest_fpu(struct kvm_vcpu *vcpu) { - preempt_disable(); + __fpregs_changes_begin(); + copy_fpregs_to_fpstate(&vcpu->arch.user_fpu); + /* PKRU is separately restored in kvm_x86_ops->run. */ __copy_kernel_to_fpregs(&vcpu->arch.guest_fpu.state, ~XFEATURE_MASK_PKRU); - preempt_enable(); + + fpregs_mark_activate(); + __fpregs_changes_end(); trace_kvm_fpu(1); } /* When vcpu_run ends, restore user space FPU context. */ static void kvm_put_guest_fpu(struct kvm_vcpu *vcpu) { - preempt_disable(); + __fpregs_changes_begin(); + copy_fpregs_to_fpstate(&vcpu->arch.guest_fpu); copy_kernel_to_fpregs(&vcpu->arch.user_fpu.state); - preempt_enable(); + + fpregs_mark_activate(); + __fpregs_changes_end(); ++vcpu->stat.fpu_reload; trace_kvm_fpu(0); }