From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 75258C3F2D1 for ; Tue, 3 Mar 2020 18:42:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5463A21775 for ; Tue, 3 Mar 2020 18:42:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730177AbgCCSmL (ORCPT ); Tue, 3 Mar 2020 13:42:11 -0500 Received: from mga03.intel.com ([134.134.136.65]:25430 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726988AbgCCSmK (ORCPT ); Tue, 3 Mar 2020 13:42:10 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Mar 2020 10:42:10 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,511,1574150400"; d="scan'208";a="263306240" Received: from sjchrist-coffee.jf.intel.com (HELO linux.intel.com) ([10.54.74.202]) by fmsmga004.fm.intel.com with ESMTP; 03 Mar 2020 10:42:09 -0800 Date: Tue, 3 Mar 2020 10:42:09 -0800 From: Sean Christopherson To: Xiaoyao Li Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , hpa@zytor.com, Paolo Bonzini , Andy Lutomirski , tony.luck@intel.com, peterz@infradead.org, fenghua.yu@intel.com, x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v3 1/8] x86/split_lock: Export handle_user_split_lock() Message-ID: <20200303184209.GP1439@linux.intel.com> References: <20200206070412.17400-1-xiaoyao.li@intel.com> <20200206070412.17400-2-xiaoyao.li@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200206070412.17400-2-xiaoyao.li@intel.com> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Feb 06, 2020 at 03:04:05PM +0800, Xiaoyao Li wrote: > Move the EFLAGS.AC check to do_alignment_check() so that > handle_user_split_lock() can be used by KVM in the future to handle #AC > caused by split lock in guest. Probably worth explaining that KVM doesn't have a @regs context and will pre-check EFLAGS.AC. > Suggested-by: Sean Christopherson > Signed-off-by: Xiaoyao Li > --- > arch/x86/include/asm/cpu.h | 4 ++-- > arch/x86/kernel/cpu/intel.c | 7 ++++--- > arch/x86/kernel/traps.c | 2 +- > 3 files changed, 7 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h > index ff6f3ca649b3..ff567afa6ee1 100644 > --- a/arch/x86/include/asm/cpu.h > +++ b/arch/x86/include/asm/cpu.h > @@ -43,11 +43,11 @@ unsigned int x86_stepping(unsigned int sig); > #ifdef CONFIG_CPU_SUP_INTEL > 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_user_split_lock(unsigned long ip); > #else > static inline void __init cpu_set_core_cap_bits(struct cpuinfo_x86 *c) {} > static inline void switch_to_sld(unsigned long tifn) {} > -static inline bool handle_user_split_lock(struct pt_regs *regs, long error_code) > +static inline bool handle_user_split_lock(unsigned long ip) > { > return false; > } > diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c > index db3e745e5d47..2b3874a96bd4 100644 > --- a/arch/x86/kernel/cpu/intel.c > +++ b/arch/x86/kernel/cpu/intel.c > @@ -1058,13 +1058,13 @@ static void split_lock_init(void) > sld_state = sld_off; > } > > -bool handle_user_split_lock(struct pt_regs *regs, long error_code) > +bool handle_user_split_lock(unsigned long ip) > { > - if ((regs->flags & X86_EFLAGS_AC) || sld_state == sld_fatal) > + if (sld_state == sld_fatal) > return false; > > pr_warn_ratelimited("#AC: %s/%d took a split_lock trap at address: 0x%lx\n", > - current->comm, current->pid, regs->ip); > + current->comm, current->pid, ip); > > /* > * Disable the split lock detection for this task so it can make > @@ -1075,6 +1075,7 @@ bool handle_user_split_lock(struct pt_regs *regs, long error_code) > set_tsk_thread_flag(current, TIF_SLD); > return true; > } > +EXPORT_SYMBOL_GPL(handle_user_split_lock); > > /* > * This function is called only when switching between tasks with > diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c > index 0ef5befaed7d..407ff9be610f 100644 > --- a/arch/x86/kernel/traps.c > +++ b/arch/x86/kernel/traps.c > @@ -304,7 +304,7 @@ dotraplinkage void do_alignment_check(struct pt_regs *regs, long error_code) > > local_irq_enable(); > > - if (handle_user_split_lock(regs, error_code)) > + if (!(regs->flags & X86_EFLAGS_AC) && handle_user_split_lock(regs->ip)) > return; > > do_trap(X86_TRAP_AC, SIGBUS, "alignment check", regs, > -- > 2.23.0 >