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From: "Xu, Like" <like.xu@intel.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	Kan Liang <kan.liang@linux.intel.com>,
	Dave Hansen <dave.hansen@intel.com>,
	wei.w.wang@intel.com, Borislav Petkov <bp@alien8.de>,
	kvm@vger.kernel.org, x86@kernel.org,
	linux-kernel@vger.kernel.org, Like Xu <like.xu@linux.intel.com>
Subject: Re: [PATCH v3 7/9] KVM: vmx/pmu: Add Arch LBR emulation and its VMCS field
Date: Thu, 4 Mar 2021 11:02:24 +0800	[thread overview]
Message-ID: <267c408c-6999-649b-d733-8d64f9cf0594@intel.com> (raw)
In-Reply-To: <YD/GrQAl1NMPHXFj@google.com>

On 2021/3/4 1:26, Sean Christopherson wrote:
> On Wed, Mar 03, 2021, Like Xu wrote:
>> New VMX controls bits for Arch LBR are added. When bit 21 in vmentry_ctrl
>> is set, VM entry will write the value from the "Guest IA32_LBR_CTL" guest
>> state field to IA32_LBR_CTL. When bit 26 in vmexit_ctrl is set, VM exit
>> will clear IA32_LBR_CTL after the value has been saved to the "Guest
>> IA32_LBR_CTL" guest state field.
> ...
>
>> @@ -2529,7 +2532,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf,
>>   	      VM_EXIT_LOAD_IA32_EFER |
>>   	      VM_EXIT_CLEAR_BNDCFGS |
>>   	      VM_EXIT_PT_CONCEAL_PIP |
>> -	      VM_EXIT_CLEAR_IA32_RTIT_CTL;
>> +	      VM_EXIT_CLEAR_IA32_RTIT_CTL |
>> +	      VM_EXIT_CLEAR_IA32_LBR_CTL;
> So, how does MSR_ARCH_LBR_CTL get restored on the host?  What if the host wants
> to keep _its_ LBR recording active while the guest is running?

Thank you!

I will add "host_lbrctlmsr" field to "struct vcpu_vmx" and
repeat the update/get_debugctlmsr() stuff.

>>   	if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_EXIT_CTLS,
>>   				&_vmexit_control) < 0)
>>   		return -EIO;
>> @@ -2553,7 +2557,8 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf,
>>   	      VM_ENTRY_LOAD_IA32_EFER |
>>   	      VM_ENTRY_LOAD_BNDCFGS |
>>   	      VM_ENTRY_PT_CONCEAL_PIP |
>> -	      VM_ENTRY_LOAD_IA32_RTIT_CTL;
>> +	      VM_ENTRY_LOAD_IA32_RTIT_CTL |
>> +	      VM_ENTRY_LOAD_IA32_LBR_CTL;
>>   	if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_ENTRY_CTLS,
>>   				&_vmentry_control) < 0)
>>   		return -EIO;
>> -- 
>> 2.29.2
>>


  reply	other threads:[~2021-03-04  3:04 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-03 13:57 [PATCH v3 0/9] KVM: x86/pmu: Guest Architectural LBR Enabling Like Xu
2021-03-03 13:57 ` [PATCH v3 1/9] perf/x86/intel: Fix a comment about guest LBR support Like Xu
2021-03-03 16:49   ` Sean Christopherson
2021-03-03 13:57 ` [PATCH v3 2/9] perf/x86/lbr: Simplify the exposure check for the LBR_INFO registers Like Xu
2021-03-03 13:57 ` [PATCH v3 3/9] perf/x86/lbr: Skip checking for the existence of LBR_TOS for Arch LBR Like Xu
2021-03-03 13:57 ` [PATCH v3 4/9] perf/x86/lbr: Use GFP_ATOMIC for cpuc->lbr_xsave memory allocation Like Xu
2021-03-03 13:57 ` [PATCH v3 5/9] KVM: vmx/pmu: Add MSR_ARCH_LBR_DEPTH emulation for Arch LBR Like Xu
2021-03-03 16:58   ` Sean Christopherson
2021-03-04  2:30     ` Xu, Like
2021-03-04 16:12       ` Sean Christopherson
2021-03-05  2:33         ` Xu, Like
2021-03-03 13:57 ` [PATCH v3 6/9] KVM: vmx/pmu: Add MSR_ARCH_LBR_CTL " Like Xu
2021-03-03 17:19   ` Sean Christopherson
2021-03-04  2:58     ` Xu, Like
2021-03-04 16:25       ` Sean Christopherson
2021-03-03 13:57 ` [PATCH v3 7/9] KVM: vmx/pmu: Add Arch LBR emulation and its VMCS field Like Xu
2021-03-03 17:26   ` Sean Christopherson
2021-03-04  3:02     ` Xu, Like [this message]
2021-03-04 17:23       ` Sean Christopherson
2021-03-05  6:35         ` Xu, Like
2021-03-03 13:57 ` [PATCH v3 8/9] KVM: x86: Expose Architectural LBR CPUID leaf Like Xu
2021-03-03 17:34   ` Sean Christopherson
2021-03-03 18:01     ` Sean Christopherson
2021-03-03 13:57 ` [PATCH v3 9/9] KVM: x86: Add XSAVE Support for Architectural LBRs Like Xu
2021-03-03 18:03   ` Sean Christopherson
2021-03-04  3:43     ` Like Xu
2021-03-04 16:31       ` Sean Christopherson
2021-03-05  2:57         ` Xu, Like
2021-03-03 13:57 ` [kvm-unit-tests PATCH] x86: Update guest LBR tests for Architectural LBR Like Xu
2021-03-03 18:05   ` Sean Christopherson

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