From patchwork Sat May 9 11:05:38 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xiaoyao Li X-Patchwork-Id: 11537909 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 84B4F15E6 for ; Sat, 9 May 2020 03:03:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 77CEA24965 for ; Sat, 9 May 2020 03:03:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728768AbgEIDDy (ORCPT ); Fri, 8 May 2020 23:03:54 -0400 Received: from mga12.intel.com ([192.55.52.136]:55120 "EHLO mga12.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728692AbgEIDDw (ORCPT ); Fri, 8 May 2020 23:03:52 -0400 IronPort-SDR: U9l+Iq81pNEVyB5k8csACETrXBqnYFWSbA+sWzf9+YzS5IgrP7HZzGLUYgjeJnB+xSaxyicstU 2UBgfPzbZ3TQ== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2020 20:03:52 -0700 IronPort-SDR: XnVfzQjeJ2drVnSfFyargOrUUqXVWmNQRzk+Vucny6ZydagwnsP8bRWSVS+Ilnsfg1/MU8DSz3 qolzq8oKEq7Q== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,370,1583222400"; d="scan'208";a="408311062" Received: from lxy-dell.sh.intel.com ([10.239.159.21]) by orsmga004.jf.intel.com with ESMTP; 08 May 2020 20:03:48 -0700 From: Xiaoyao Li To: Paolo Bonzini , Thomas Gleixner , Sean Christopherson , kvm@vger.kernel.org Cc: linux-kernel@vger.kernel.org, x86@kernel.org, Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , Andy Lutomirski , peterz@infradead.org, Arvind Sankar , Tony Luck , Fenghua Yu , Xiaoyao Li Subject: [PATCH v9 4/8] x86/split_lock: Introduce split_lock_virt_switch() and two wrappers Date: Sat, 9 May 2020 19:05:38 +0800 Message-Id: <20200509110542.8159-5-xiaoyao.li@intel.com> X-Mailer: git-send-email 2.18.2 In-Reply-To: <20200509110542.8159-1-xiaoyao.li@intel.com> References: <20200509110542.8159-1-xiaoyao.li@intel.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Introduce split_lock_virt_switch(), which is used for toggling split lock detection setting as well as updating TIF_SLD_DISABLED flag to make them consistent. Note, it can only be used in sld warn mode, i.e., X86_FEATURE_SPLIT_LOCK_DETECT && !X86_FEATURE_SLD_FATAL. The FATAL check is handled by wrappers, split_lock_set_guest() and split_lock_restore_host(), that will be used by KVM when virtualizing split lock detection for guest in the future. Signed-off-by: Xiaoyao Li --- arch/x86/include/asm/cpu.h | 33 +++++++++++++++++++++++++++++++++ arch/x86/kernel/cpu/intel.c | 20 ++++++++++++++++++++ 2 files changed, 53 insertions(+) diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h index dd17c2da1af5..a57f00f1d5b5 100644 --- a/arch/x86/include/asm/cpu.h +++ b/arch/x86/include/asm/cpu.h @@ -45,6 +45,7 @@ extern void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c); extern void switch_to_sld(unsigned long tifn); extern bool handle_user_split_lock(struct pt_regs *regs, long error_code); extern bool handle_guest_split_lock(unsigned long ip); +extern bool split_lock_virt_switch(bool on); #else static inline void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c) {} static inline void switch_to_sld(unsigned long tifn) {} @@ -57,5 +58,37 @@ static inline bool handle_guest_split_lock(unsigned long ip) { return false; } + +static inline bool split_lock_virt_switch(bool on) { return false; } #endif + +/** + * split_lock_set_guest - Set SLD state for a guest + * @guest_sld_on: If SLD is on in the guest + * + * returns: %true if SLD was enabled in the task + * + * Must be called when X86_FEATURE_SPLIT_LOCK_DETECT is available. + */ +static inline bool split_lock_set_guest(bool guest_sld_on) +{ + if (static_cpu_has(X86_FEATURE_SLD_FATAL)) + return true; + + return split_lock_virt_switch(guest_sld_on); +} + +/** + * split_lock_restore_host - Restore host SLD state + * @host_sld_on: If SLD is on in the host + * + * Must be called when X86_FEATURE_SPLIT_LOCK_DETECT is available. + */ +static inline void split_lock_restore_host(bool host_sld_on) +{ + if (static_cpu_has(X86_FEATURE_SLD_FATAL)) + return; + + split_lock_virt_switch(host_sld_on); +} #endif /* _ASM_X86_CPU_H */ diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index 93b8ccf2fa11..1e2a74e8c592 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -1062,6 +1062,26 @@ static void split_lock_init(void) split_lock_verify_msr(boot_cpu_has(X86_FEATURE_SPLIT_LOCK_DETECT)); } +/* + * It should never be called directly but should use split_lock_set_guest() + * and split_lock_restore_host() instead. + * + * The caller needs to be in preemption disabled context to ensure + * MSR state and TIF_SLD_DISABLED state consistent. + */ +bool split_lock_virt_switch(bool on) +{ + bool was_on = !test_thread_flag(TIF_SLD_DISABLED); + + if (on != was_on) { + sld_update_msr(on); + update_thread_flag(TIF_SLD_DISABLED, !on); + } + + return was_on; +} +EXPORT_SYMBOL_GPL(split_lock_virt_switch); + static void split_lock_warn(unsigned long ip) { pr_warn_ratelimited("#AC: %s/%d took a split_lock trap at address: 0x%lx\n",