From patchwork Tue Oct 12 18:40:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Gleixner X-Patchwork-Id: 12553513 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 34FB1C433F5 for ; Tue, 12 Oct 2021 18:44:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0DA9B60F38 for ; Tue, 12 Oct 2021 18:44:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235155AbhJLSq4 (ORCPT ); Tue, 12 Oct 2021 14:46:56 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:57634 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234995AbhJLSqz (ORCPT ); Tue, 12 Oct 2021 14:46:55 -0400 From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1634064033; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=KW+IJ7OIyygtO/OUib0E/8GQRDwfz133sFxAz7WGAxc=; b=if4AgnZt3vh78PzErZ4D+P8AL4EAGFPgHqgITlTOjCtWExcVjyr+WRGutjEkhGdAXGI3Tf 8bEBavF4jCqR92er3KEb/7PR2JGmzw08HTtArGN92IcY6YL9SspWR1FSeWWYKAOoSgq3n/ B+rdjCvnVfjy3FbKkzohq9r8ONHxRFKo00fcuLeNlFbxeirt085rcheR4Czi1nPKYGrTYw NvtDZB/JQ26kslfqDrVp5pIWf/fnUFCVJ+NjFOGATbTCznkiEaI/8/wxuNGvT4vbRqDl0B Dx68Uwly/S5e6/4G0q7WeY6B+IrBbLld+JdO8KyWv6UWmNWnpXWlLt9bA1kpzw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1634064033; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=KW+IJ7OIyygtO/OUib0E/8GQRDwfz133sFxAz7WGAxc=; b=Kd4INlPzpimcW+3qnVdzxma4uFCdRF49G8PXqO/bBZxtq+FMdI0w2Q1OxHLA2OBChJNnI3 5w81b0QJQyGwkkBw== To: Paolo Bonzini , LKML Cc: x86@kernel.org, "Chang S. Bae" , Dave Hansen , Arjan van de Ven , kvm@vger.kernel.org Subject: [patch V2 16/31] x86/fpu: Replace KVMs home brewed FPU copy to user In-Reply-To: <87fst6b0f5.ffs@tglx> References: <20211011215813.558681373@linutronix.de> <20211011223611.249593446@linutronix.de> <0d222978-014a-cdcb-f8aa-5b3179cb0809@redhat.com> <87fst6b0f5.ffs@tglx> Date: Tue, 12 Oct 2021 20:40:32 +0200 Message-ID: <87zgre9jdr.ffs@tglx> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Similar to the copy from user function the FPU core has this already implemented with all bells and whistles. Get rid of the duplicated code and use the core functionality. The memset(0) of the buffer is not required as it is already allocated with kzalloc() at the call site. Signed-off-by: Thomas Gleixner Cc: kvm@vger.kernel.org Cc: Paolo Bonzini --- V2: Add the missing xsave header assignment in the !XSAVE path and explain the memset(0) removal in the changelog - Paolo Rename the function and fix subject - Borislav --- arch/x86/include/asm/fpu/api.h | 1 arch/x86/kernel/fpu/core.c | 18 +++++++++++++ arch/x86/kvm/x86.c | 56 ++--------------------------------------- 3 files changed, 22 insertions(+), 53 deletions(-) --- a/arch/x86/include/asm/fpu/api.h +++ b/arch/x86/include/asm/fpu/api.h @@ -117,5 +117,6 @@ extern void fpu_init_fpstate_user(struct extern void fpu_swap_kvm_fpu(struct fpu *save, struct fpu *rstor, u64 restore_mask); extern int fpu_copy_kvm_uabi_to_fpstate(struct fpu *fpu, const void *buf, u64 xcr0, u32 *pkru); +extern void fpu_copy_fpstate_to_kvm_uabi(struct fpu *fpu, void *buf, unsigned int size, u32 pkru); #endif /* _ASM_X86_FPU_API_H */ --- a/arch/x86/kernel/fpu/core.c +++ b/arch/x86/kernel/fpu/core.c @@ -175,6 +175,24 @@ void fpu_swap_kvm_fpu(struct fpu *save, } EXPORT_SYMBOL_GPL(fpu_swap_kvm_fpu); +void fpu_copy_fpstate_to_kvm_uabi(struct fpu *fpu, void *buf, + unsigned int size, u32 pkru) +{ + union fpregs_state *kstate = &fpu->state; + union fpregs_state *ustate = buf; + struct membuf mb = { .p = buf, .left = size }; + + if (cpu_feature_enabled(X86_FEATURE_XSAVE)) { + __copy_xstate_to_uabi_buf(mb, &kstate->xsave, pkru, + XSTATE_COPY_XSAVE); + } else { + memcpy(&ustate->fxsave, &kstate->fxsave, sizeof(ustate->fxsave)); + /* Make it restorable on a XSAVE enabled host */ + ustate->xsave.header.xfeatures = XFEATURE_MASK_FPSSE; + } +} +EXPORT_SYMBOL_GPL(fpu_copy_fpstate_to_kvm_uabi); + int fpu_copy_kvm_uabi_to_fpstate(struct fpu *fpu, const void *buf, u64 xcr0, u32 *vpkru) { --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -4695,65 +4695,15 @@ static int kvm_vcpu_ioctl_x86_set_debugr return 0; } -static void fill_xsave(u8 *dest, struct kvm_vcpu *vcpu) -{ - struct xregs_state *xsave = &vcpu->arch.guest_fpu->state.xsave; - u64 xstate_bv = xsave->header.xfeatures; - u64 valid; - - /* - * Copy legacy XSAVE area, to avoid complications with CPUID - * leaves 0 and 1 in the loop below. - */ - memcpy(dest, xsave, XSAVE_HDR_OFFSET); - - /* Set XSTATE_BV */ - xstate_bv &= vcpu->arch.guest_supported_xcr0 | XFEATURE_MASK_FPSSE; - *(u64 *)(dest + XSAVE_HDR_OFFSET) = xstate_bv; - - /* - * Copy each region from the possibly compacted offset to the - * non-compacted offset. - */ - valid = xstate_bv & ~XFEATURE_MASK_FPSSE; - while (valid) { - u32 size, offset, ecx, edx; - u64 xfeature_mask = valid & -valid; - int xfeature_nr = fls64(xfeature_mask) - 1; - void *src; - - cpuid_count(XSTATE_CPUID, xfeature_nr, - &size, &offset, &ecx, &edx); - - if (xfeature_nr == XFEATURE_PKRU) { - memcpy(dest + offset, &vcpu->arch.pkru, - sizeof(vcpu->arch.pkru)); - } else { - src = get_xsave_addr(xsave, xfeature_nr); - if (src) - memcpy(dest + offset, src, size); - } - - valid -= xfeature_mask; - } -} - static void kvm_vcpu_ioctl_x86_get_xsave(struct kvm_vcpu *vcpu, struct kvm_xsave *guest_xsave) { if (!vcpu->arch.guest_fpu) return; - if (boot_cpu_has(X86_FEATURE_XSAVE)) { - memset(guest_xsave, 0, sizeof(struct kvm_xsave)); - fill_xsave((u8 *) guest_xsave->region, vcpu); - } else { - memcpy(guest_xsave->region, - &vcpu->arch.guest_fpu->state.fxsave, - sizeof(struct fxregs_state)); - *(u64 *)&guest_xsave->region[XSAVE_HDR_OFFSET / sizeof(u32)] = - XFEATURE_MASK_FPSSE; - } + fpu_copy_fpstate_to_kvm_uabi(vcpu->arch.guest_fpu, guest_xsave->region, + sizeof(guest_xsave->region), + vcpu->arch.pkru); } static int kvm_vcpu_ioctl_x86_set_xsave(struct kvm_vcpu *vcpu,