From: Sean Christopherson <seanjc@google.com>
To: Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
Aaron Lewis <aaronlewis@google.com>,
Weijiang Yang <weijiang.yang@intel.com>,
Like Xu <likexu@tencent.com>
Subject: [PATCH 5/6] KVM: x86/pmu: Don't tell userspace to save MSRs for non-existent fixed PMCs
Date: Tue, 24 Jan 2023 23:49:04 +0000 [thread overview]
Message-ID: <20230124234905.3774678-6-seanjc@google.com> (raw)
In-Reply-To: <20230124234905.3774678-1-seanjc@google.com>
From: Like Xu <likexu@tencent.com>
Limit the set of MSRs for fixed PMU counters based on the number of fixed
counters actually supported by the host so that userspace doesn't waste
time saving and restoring dummy values.
Signed-off-by: Like Xu <likexu@tencent.com>
[sean: split for !enable_pmu logic, drop min(), write changelog]
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/x86.c | 5 +++++
2 files changed, 6 insertions(+)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index cd0151e6af62..adb92fc4d7c9 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -514,6 +514,7 @@ struct kvm_pmc {
#define MSR_ARCH_PERFMON_PERFCTR_MAX (MSR_ARCH_PERFMON_PERFCTR0 + KVM_INTEL_PMC_MAX_GENERIC - 1)
#define MSR_ARCH_PERFMON_EVENTSEL_MAX (MSR_ARCH_PERFMON_EVENTSEL0 + KVM_INTEL_PMC_MAX_GENERIC - 1)
#define KVM_PMC_MAX_FIXED 3
+#define MSR_ARCH_PERFMON_FIXED_CTR_MAX (MSR_ARCH_PERFMON_FIXED_CTR0 + KVM_PMC_MAX_FIXED - 1)
#define KVM_AMD_PMC_MAX_GENERIC 6
struct kvm_pmu {
unsigned nr_arch_gp_counters;
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 25da2cc09e55..3c49c86b973d 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -7055,6 +7055,11 @@ static void kvm_probe_msr_to_save(u32 msr_index)
kvm_pmu_cap.num_counters_gp)
return;
break;
+ case MSR_ARCH_PERFMON_FIXED_CTR0 ... MSR_ARCH_PERFMON_FIXED_CTR_MAX:
+ if (msr_index - MSR_ARCH_PERFMON_FIXED_CTR0 >=
+ kvm_pmu_cap.num_counters_fixed)
+ return;
+ break;
case MSR_IA32_XFD:
case MSR_IA32_XFD_ERR:
if (!kvm_cpu_cap_has(X86_FEATURE_XFD))
--
2.39.1.456.gfc5497dd1b-goog
next prev parent reply other threads:[~2023-01-24 23:49 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-24 23:48 [PATCH 0/6] KVM: x86/pmu: Misc PMU MSR fixes Sean Christopherson
2023-01-24 23:49 ` [PATCH 1/6] KVM: x86/pmu: Cap kvm_pmu_cap.num_counters_gp at KVM's internal max Sean Christopherson
2023-01-24 23:49 ` [PATCH 2/6] KVM: x86/pmu: Gate all "unimplemented MSR" prints on report_ignored_msrs Sean Christopherson
2023-01-25 9:29 ` Vitaly Kuznetsov
2023-01-31 11:46 ` Like Xu
2023-01-31 16:08 ` Sean Christopherson
2023-01-24 23:49 ` [PATCH 3/6] KVM: x86/pmu: Use separate array for defining "PMU MSRs to save" Sean Christopherson
2023-02-10 13:23 ` Yu Zhang
2023-02-10 16:32 ` Sean Christopherson
2023-01-24 23:49 ` [PATCH 4/6] KVM: x86/pmu: Don't tell userspace to save PMU MSRs if PMU is disabled Sean Christopherson
2023-01-24 23:49 ` Sean Christopherson [this message]
2023-01-24 23:49 ` [PATCH 6/6] KVM: x86/pmu: Provide "error" semantics for unsupported-but-known PMU MSRs Sean Christopherson
2023-01-28 0:07 ` [PATCH 0/6] KVM: x86/pmu: Misc PMU MSR fixes Sean Christopherson
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