The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 098f4c061ea10b777033b71c10bd9fd706820ee9 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to '<stable@xxxxxxxxxxxxxxx>' --in-reply-to '2023050609-dust-unequal-f736@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: 098f4c061ea1 ("KVM: x86/pmu: Disallow legacy LBRs if architectural LBRs are available") bec46859fb9d ("KVM: x86: Track supported PERF_CAPABILITIES in kvm_caps") 0b9ca98b7229 ("perf/x86/core: Zero @lbr instead of returning -1 in x86_perf_get_lbr() stub") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 098f4c061ea10b777033b71c10bd9fd706820ee9 Mon Sep 17 00:00:00 2001 From: Sean Christopherson <seanjc@xxxxxxxxxx> Date: Sat, 28 Jan 2023 00:14:27 +0000 Subject: [PATCH] KVM: x86/pmu: Disallow legacy LBRs if architectural LBRs are available Disallow enabling LBR support if the CPU supports architectural LBRs. Traditional LBR support is absent on CPU models that have architectural LBRs, and KVM doesn't yet support arch LBRs, i.e. KVM will pass through non-existent MSRs if userspace enables LBRs for the guest. Cc: stable@xxxxxxxxxxxxxxx Cc: Yang Weijiang <weijiang.yang@xxxxxxxxx> Cc: Like Xu <like.xu.linux@xxxxxxxxx> Reported-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> Fixes: be635e34c284 ("KVM: vmx/pmu: Expose LBR_FMT in the MSR_IA32_PERF_CAPABILITIES") Tested-by: Like Xu <likexu@xxxxxxxxxxx> Link: https://lore.kernel.org/r/20230128001427.2548858-1-seanjc@xxxxxxxxxx Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx> diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index d7bf14abdba1..c18f74899f01 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -7793,9 +7793,11 @@ static u64 vmx_get_perf_capabilities(void) if (boot_cpu_has(X86_FEATURE_PDCM)) rdmsrl(MSR_IA32_PERF_CAPABILITIES, host_perf_cap); - x86_perf_get_lbr(&lbr); - if (lbr.nr) - perf_cap |= host_perf_cap & PMU_CAP_LBR_FMT; + if (!cpu_feature_enabled(X86_FEATURE_ARCH_LBR)) { + x86_perf_get_lbr(&lbr); + if (lbr.nr) + perf_cap |= host_perf_cap & PMU_CAP_LBR_FMT; + } if (vmx_pebs_supported()) { perf_cap |= host_perf_cap & PERF_CAP_PEBS_MASK;
