From: "Luck, Tony" <tony.luck@intel.com>
To: Xiaoyao Li <xiaoyao.li@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
hpa@zytor.com, Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <sean.j.christopherson@intel.com>,
kvm@vger.kernel.org, x86@kernel.org,
linux-kernel@vger.kernel.org, Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Arvind Sankar <nivedita@alum.mit.edu>,
Fenghua Yu <fenghua.yu@intel.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Jim Mattson <jmattson@google.com>
Subject: Re: [PATCH v5 4/9] x86/split_lock: Export handle_user_split_lock()
Date: Fri, 20 Mar 2020 17:48:09 -0700 [thread overview]
Message-ID: <20200321004809.GD6578@agluck-desk2.amr.corp.intel.com> (raw)
In-Reply-To: <20200315050517.127446-5-xiaoyao.li@intel.com>
On Sun, Mar 15, 2020 at 01:05:12PM +0800, Xiaoyao Li wrote:
> In the future, KVM will use handle_user_split_lock() to handle #AC
> caused by split lock in guest. Due to the fact that KVM doesn't have
> a @regs context and will pre-check EFLASG.AC, move the EFLAGS.AC check
> to do_alignment_check().
>
> Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
> ---
> 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 3eeab717a0d0..c401d174c8db 100644
> --- a/arch/x86/kernel/cpu/intel.c
> +++ b/arch/x86/kernel/cpu/intel.c
> @@ -1102,13 +1102,13 @@ static void split_lock_init(struct cpuinfo_x86 *c)
> sld_state = sld_disable;
> }
>
> -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
> @@ -1119,6 +1119,7 @@ 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,
> --
> 2.20.1
>
Looks good to me.
Reviewed-by: Tony Luck <tony.luck@intel.com>
next prev parent reply other threads:[~2020-03-21 0:48 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-15 5:05 [PATCH v5 0/9] x86/split_lock: Add feature split lock detection Xiaoyao Li
2020-03-15 5:05 ` [PATCH v5 1/9] x86/split_lock: Rework the initialization flow of " Xiaoyao Li
2020-03-21 0:41 ` Luck, Tony
2020-03-23 17:02 ` Thomas Gleixner
2020-03-23 20:24 ` Thomas Gleixner
2020-03-24 1:10 ` Xiaoyao Li
2020-03-24 10:29 ` Thomas Gleixner
2020-03-25 0:18 ` Xiaoyao Li
2020-03-25 0:52 ` Thomas Gleixner
2020-03-24 11:51 ` Xiaoyao Li
2020-03-24 13:31 ` Thomas Gleixner
2020-03-15 5:05 ` [PATCH v5 2/9] x86/split_lock: Avoid runtime reads of the TEST_CTRL MSR Xiaoyao Li
2020-03-21 0:43 ` Luck, Tony
2020-03-23 17:06 ` Thomas Gleixner
2020-03-23 17:06 ` Thomas Gleixner
2020-03-24 1:16 ` Xiaoyao Li
2020-03-15 5:05 ` [PATCH v5 3/9] x86/split_lock: Re-define the kernel param option for split_lock_detect Xiaoyao Li
2020-03-21 0:46 ` Luck, Tony
2020-03-23 17:10 ` Thomas Gleixner
2020-03-24 1:38 ` Xiaoyao Li
2020-03-24 10:40 ` Thomas Gleixner
2020-03-24 18:02 ` Sean Christopherson
2020-03-24 18:42 ` Thomas Gleixner
2020-03-25 0:43 ` Xiaoyao Li
2020-03-25 1:03 ` Thomas Gleixner
2020-03-15 5:05 ` [PATCH v5 4/9] x86/split_lock: Export handle_user_split_lock() Xiaoyao Li
2020-03-21 0:48 ` Luck, Tony [this message]
2020-03-15 5:05 ` [PATCH v5 5/9] kvm: x86: Emulate split-lock access as a write Xiaoyao Li
2020-03-15 5:05 ` [PATCH v5 6/9] kvm: vmx: Extend VMX's #AC interceptor to handle split lock #AC happens in guest Xiaoyao Li
2020-03-15 5:05 ` [PATCH v5 7/9] kvm: x86: Emulate MSR IA32_CORE_CAPABILITIES Xiaoyao Li
2020-03-15 5:05 ` [PATCH v5 8/9] kvm: vmx: Enable MSR_TEST_CTRL for intel guest Xiaoyao Li
2020-03-15 5:05 ` [PATCH v5 9/9] x86: vmx: virtualize split lock detection Xiaoyao Li
2020-03-23 2:18 ` [PATCH v5 0/9] x86/split_lock: Add feature " Xiaoyao Li
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