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From: Arvind Sankar <nivedita@alum.mit.edu>
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>,
	Andy Lutomirski <luto@kernel.org>,
	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 3/8] x86/split_lock: Cache the value of MSR_TEST_CTRL in percpu data
Date: Thu, 6 Feb 2020 15:23:47 -0500	[thread overview]
Message-ID: <20200206202346.GA2742055@rani.riverdale.lan> (raw)
In-Reply-To: <20200206070412.17400-4-xiaoyao.li@intel.com>

On Thu, Feb 06, 2020 at 03:04:07PM +0800, Xiaoyao Li wrote:
> Cache the value of MSR_TEST_CTRL in percpu data msr_test_ctrl_cache,
> which will be used by KVM module.
> 
> It also avoids an expensive RDMSR instruction if SLD needs to be context
> switched.
> 
> Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
> ---
>  arch/x86/include/asm/cpu.h  |  2 ++
>  arch/x86/kernel/cpu/intel.c | 19 ++++++++++++-------
>  2 files changed, 14 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
> index ff567afa6ee1..2b20829db450 100644
> --- a/arch/x86/include/asm/cpu.h
> +++ b/arch/x86/include/asm/cpu.h
> @@ -27,6 +27,8 @@ struct x86_cpu {
>  };
>  
>  #ifdef CONFIG_HOTPLUG_CPU
> +DECLARE_PER_CPU(u64, msr_test_ctrl_cache);
> +

Why does this depend on HOTPLUG_CPU?

  reply	other threads:[~2020-02-06 20:23 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-06  7:04 [PATCH v3 0/8] kvm/split_lock: Add feature split lock detection support in kvm Xiaoyao Li
2020-02-06  7:04 ` [PATCH v3 1/8] x86/split_lock: Export handle_user_split_lock() Xiaoyao Li
2020-03-03 18:42   ` Sean Christopherson
2020-02-06  7:04 ` [PATCH v3 2/8] x86/split_lock: Ensure X86_FEATURE_SPLIT_LOCK_DETECT means the existence of feature Xiaoyao Li
2020-03-03 18:55   ` Sean Christopherson
2020-03-03 19:41     ` Sean Christopherson
2020-03-04  1:49       ` Xiaoyao Li
2020-03-05 16:23         ` Sean Christopherson
2020-03-06  2:15           ` Xiaoyao Li
2020-03-04  2:20     ` Xiaoyao Li
2020-02-06  7:04 ` [PATCH v3 3/8] x86/split_lock: Cache the value of MSR_TEST_CTRL in percpu data Xiaoyao Li
2020-02-06 20:23   ` Arvind Sankar [this message]
2020-02-07  4:18     ` Xiaoyao Li
2020-03-03 19:18   ` Sean Christopherson
2020-03-05  6:48     ` Xiaoyao Li
2020-02-06  7:04 ` [PATCH v3 4/8] x86/split_lock: Add and export split_lock_detect_enabled() and split_lock_detect_fatal() Xiaoyao Li
2020-03-03 18:59   ` Sean Christopherson
2020-02-06  7:04 ` [PATCH v3 5/8] kvm: x86: Emulate split-lock access as a write Xiaoyao Li
2020-02-06  7:04 ` [PATCH v3 6/8] kvm: vmx: Extend VMX's #AC interceptor to handle split lock #AC happens in guest Xiaoyao Li
2020-03-03 19:08   ` Sean Christopherson
2020-02-06  7:04 ` [PATCH v3 7/8] kvm: x86: Emulate MSR IA32_CORE_CAPABILITIES Xiaoyao Li
2020-02-06  7:04 ` [PATCH v3 8/8] x86: vmx: virtualize split lock detection Xiaoyao Li
2020-02-07 18:27   ` Arvind Sankar
2020-02-08  4:51     ` Xiaoyao Li
2020-03-03 19:30   ` Sean Christopherson
2020-03-05 14:16     ` Xiaoyao Li
2020-03-05 16:49       ` Sean Christopherson
2020-03-06  0:29         ` Xiaoyao Li

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