From: "Yang, Weijiang" <weijiang.yang@intel.com>
To: Sean Christopherson <seanjc@google.com>
Cc: <pbonzini@redhat.com>, <jmattson@google.com>,
<kvm@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<like.xu.linux@gmail.com>, <kan.liang@linux.intel.com>,
<wei.w.wang@intel.com>
Subject: Re: [PATCH v2 13/15] KVM: x86/vmx: Save/Restore guest Arch LBR Ctrl msr at SMM entry/exit
Date: Mon, 30 Jan 2023 20:50:48 +0800 [thread overview]
Message-ID: <a3cd4e64-aeb6-b0fb-36cb-ad16a6e8b1d7@intel.com> (raw)
In-Reply-To: <Y9RMASMnzc3tPqvO@google.com>
On 1/28/2023 6:11 AM, Sean Christopherson wrote:
> On Thu, Nov 24, 2022, Yang Weijiang wrote:
>> Per SDM 3B Chapter 18: "IA32_LBR_CTL.LBREn is saved and cleared on #SMI,
>> and restored on RSM", store guest IA32_LBR_CTL in SMRAM and clear LBREn
>> in VMCS at SMM entry, and do reverse things at SMM exit.
[...]
>> @@ -8006,11 +8006,21 @@ static int vmx_enter_smm(struct kvm_vcpu *vcpu, union kvm_smram *smram)
>> vmx->nested.smm.vmxon = vmx->nested.vmxon;
>> vmx->nested.vmxon = false;
>> vmx_clear_hlt(vcpu);
>> +
>> + if (kvm_cpu_cap_has(X86_FEATURE_ARCH_LBR) &&
>> + guest_cpuid_has(vcpu, X86_FEATURE_LM)) {
> Uh, so this arbitrary dependency on 64-bit vCPUs needs to be factored into the
> enabling. And KVM should WARN if arch LBRs get enabled for a 32-bit vCPU.
OK, will add the check while creating event.
>
>> + u64 ctl = vmcs_read64(GUEST_IA32_LBR_CTL);
>> +
>> + smram->smram64.arch_lbr_ctl = ctl;
>> + vmcs_write64(GUEST_IA32_LBR_CTL, ctl & ~ARCH_LBR_CTL_LBREN);
>> + }
>> +
>> return 0;
>> }
>>
>> static int vmx_leave_smm(struct kvm_vcpu *vcpu, const union kvm_smram *smram)
>> {
>> + struct lbr_desc *lbr_desc = vcpu_to_lbr_desc(vcpu);
>> struct vcpu_vmx *vmx = to_vmx(vcpu);
>> int ret;
>>
>> @@ -8027,6 +8037,18 @@ static int vmx_leave_smm(struct kvm_vcpu *vcpu, const union kvm_smram *smram)
>> vmx->nested.nested_run_pending = 1;
>> vmx->nested.smm.guest_mode = false;
>> }
>> +
>> + if (kvm_cpu_cap_has(X86_FEATURE_ARCH_LBR) &&
>> + guest_cpuid_has(vcpu, X86_FEATURE_LM)) {
>> + u64 ctl = smram->smram64.arch_lbr_ctl;
>> +
>> + vmcs_write64(GUEST_IA32_LBR_CTL, ctl & ARCH_LBR_CTL_LBREN);
> IIUC, this should set only LBREn and preserve all other bits, not clobber the
> entire MSR.
Oops, it's a typo, thanks!
>
>> +
>> + if (intel_pmu_lbr_is_enabled(vcpu) &&
>> + (ctl & ARCH_LBR_CTL_LBREN) && !lbr_desc->event)
>> + intel_pmu_create_guest_lbr_event(vcpu);
>> + }
>> +
>> return 0;
>> }
>>
>> --
>> 2.27.0
>>
next prev parent reply other threads:[~2023-01-30 12:51 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-11-25 4:05 [PATCH v2 00/15] Introduce Architectural LBR for vPMU Yang Weijiang
2022-11-25 4:05 ` [PATCH v2 01/15] perf/x86/lbr: Simplify the exposure check for the LBR_INFO registers Yang Weijiang
2022-12-22 10:57 ` Like Xu
2022-12-22 13:29 ` Peter Zijlstra
2022-12-22 17:41 ` Sean Christopherson
2022-12-23 2:12 ` Like Xu
2022-12-27 11:58 ` [tip: perf/core] " tip-bot2 for Like Xu
2022-11-25 4:05 ` [PATCH v2 02/15] KVM: x86: Report XSS as an MSR to be saved if there are supported features Yang Weijiang
2022-11-25 4:05 ` [PATCH v2 03/15] KVM: x86: Refresh CPUID on writes to MSR_IA32_XSS Yang Weijiang
2023-01-26 19:50 ` Sean Christopherson
2023-01-30 6:33 ` Yang, Weijiang
2022-11-25 4:05 ` [PATCH v2 04/15] KVM: PMU: disable LBR handling if architectural LBR is available Yang Weijiang
2023-01-27 20:10 ` Sean Christopherson
2023-01-30 8:10 ` Yang, Weijiang
2022-11-25 4:05 ` [PATCH v2 05/15] KVM: vmx/pmu: Emulate MSR_ARCH_LBR_DEPTH for guest Arch LBR Yang Weijiang
2022-12-22 11:00 ` Like Xu
2022-12-25 4:30 ` Yang, Weijiang
2022-12-22 11:15 ` Like Xu
2023-01-27 20:25 ` Sean Christopherson
2023-01-30 11:46 ` Yang, Weijiang
2022-11-25 4:05 ` [PATCH v2 06/15] KVM: vmx/pmu: Emulate MSR_ARCH_LBR_CTL " Yang Weijiang
2022-12-22 11:09 ` Like Xu
2022-12-25 4:27 ` Yang, Weijiang
2022-12-22 11:19 ` Like Xu
2022-12-25 4:16 ` Yang, Weijiang
2022-12-22 11:24 ` Like Xu
2022-12-25 4:08 ` Yang, Weijiang
2023-01-27 21:42 ` Sean Christopherson
2022-11-25 4:05 ` [PATCH v2 07/15] KVM: VMX: Support passthrough of architectural LBRs Yang Weijiang
2022-11-25 4:05 ` [PATCH v2 08/15] KVM: x86: Add Arch LBR MSRs to msrs_to_save_all list Yang Weijiang
2023-01-27 21:43 ` Sean Christopherson
2023-01-30 12:27 ` Yang, Weijiang
2022-11-25 4:05 ` [PATCH v2 09/15] KVM: x86: Refine the matching and clearing logic for supported_xss Yang Weijiang
2023-01-27 21:46 ` Sean Christopherson
2023-01-30 12:37 ` Yang, Weijiang
2022-11-25 4:05 ` [PATCH v2 10/15] KVM: x86/vmx: Check Arch LBR config when return perf capabilities Yang Weijiang
2022-12-22 11:06 ` Like Xu
2022-12-25 4:28 ` Yang, Weijiang
2023-01-27 22:04 ` Sean Christopherson
2022-11-25 4:06 ` [PATCH v2 11/15] KVM: x86: Add XSAVE Support for Architectural LBR Yang Weijiang
2023-01-27 22:07 ` Sean Christopherson
2023-01-30 13:13 ` Yang, Weijiang
2022-11-25 4:06 ` [PATCH v2 12/15] KVM: x86/vmx: Disable Arch LBREn bit in #DB and warm reset Yang Weijiang
2022-12-22 11:22 ` Like Xu
2022-12-25 4:12 ` Yang, Weijiang
2023-01-27 22:09 ` Sean Christopherson
2023-01-30 13:09 ` Yang, Weijiang
2022-11-25 4:06 ` [PATCH v2 13/15] KVM: x86/vmx: Save/Restore guest Arch LBR Ctrl msr at SMM entry/exit Yang Weijiang
2023-01-27 22:11 ` Sean Christopherson
2023-01-30 12:50 ` Yang, Weijiang [this message]
2022-11-25 4:06 ` [PATCH v2 14/15] KVM: x86: Add Arch LBR data MSR access interface Yang Weijiang
2023-01-27 22:13 ` Sean Christopherson
2023-01-30 12:46 ` Yang, Weijiang
2023-01-30 17:30 ` Sean Christopherson
2023-01-31 13:14 ` Yang, Weijiang
2023-01-31 16:05 ` Sean Christopherson
2022-11-25 4:06 ` [PATCH v2 15/15] KVM: x86/cpuid: Advertise Arch LBR feature in CPUID Yang Weijiang
2022-12-22 11:03 ` Like Xu
2022-12-25 4:31 ` Yang, Weijiang
2023-01-27 22:15 ` Sean Christopherson
2023-01-12 1:57 ` [PATCH v2 00/15] Introduce Architectural LBR for vPMU Yang, Weijiang
2023-01-27 22:46 ` Sean Christopherson
2023-01-30 13:38 ` Yang, Weijiang
2023-06-05 9:50 ` Like Xu
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