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From: Like Xu <like.xu.linux@gmail.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v4 08/12] KVM: x86/pmu: Disable vPMU if the minimum num of counters isn't met
Date: Tue, 14 Feb 2023 13:07:53 +0800	[thread overview]
Message-ID: <20230214050757.9623-9-likexu@tencent.com> (raw)
In-Reply-To: <20230214050757.9623-1-likexu@tencent.com>

From: Like Xu <likexu@tencent.com>

For compatibility with old software, KVM/AMD should never report less
than four counters if vPMU is supported. Thus KVM should sanity check
the number of counters enumerated by perf and explicitly disable vPMU
support if the min isn't met. E.g. if KVM needs 4 counters and perf says
there are 3, then something is wrong and enumerating 4 to the guest
is only going to cause more troubles.

Suggested-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Like Xu <likexu@tencent.com>
---
 arch/x86/kvm/pmu.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/x86/kvm/pmu.h b/arch/x86/kvm/pmu.h
index d1cc02c8da88..46db5404894e 100644
--- a/arch/x86/kvm/pmu.h
+++ b/arch/x86/kvm/pmu.h
@@ -170,6 +170,12 @@ static inline void kvm_init_pmu_capability(const struct kvm_pmu_ops *pmu_ops)
 	if ((is_intel && !kvm_pmu_cap.version) || !kvm_pmu_cap.num_counters_gp)
 		enable_pmu = false;
 
+	/*
+	 * For AMD, disable vPMU if the minimum number of counters isn't met.
+	 */
+	if (!is_intel && kvm_pmu_cap.num_counters_gp < AMD64_NUM_COUNTERS)
+		enable_pmu = false;
+
 	if (!enable_pmu) {
 		memset(&kvm_pmu_cap, 0, sizeof(kvm_pmu_cap));
 		return;
-- 
2.39.1


  parent reply	other threads:[~2023-02-14  5:09 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-02-14  5:07 [PATCH v4 00/12] KVM: x86: Add AMD Guest PerfMonV2 PMU support Like Xu
2023-02-14  5:07 ` [PATCH v4 01/12] KVM: x86/pmu: Rename pmc_is_enabled() to pmc_is_globally_enabled() Like Xu
2023-02-14  5:07 ` [PATCH v4 02/12] KVM: VMX: Refactor intel_pmu_set_msr() to align with other set_msr() helpers Like Xu
2023-02-16 21:13   ` Sean Christopherson
2023-02-21  8:44     ` Like Xu
2023-03-23  7:43       ` Like Xu
2023-03-23 14:28         ` Sean Christopherson
2023-02-14  5:07 ` [PATCH v4 03/12] KVM: x86/pmu: Rewrite reprogram_counters() to improve performance Like Xu
2023-02-14  5:07 ` [PATCH v4 04/12] KVM: x86/pmu: Expose reprogram_counters() in pmu.h Like Xu
2023-02-14  5:07 ` [PATCH v4 05/12] KVM: x86/pmu: Error when user sets the GLOBAL_STATUS reserved bits Like Xu
2023-04-06 23:45   ` Sean Christopherson
2023-04-07  5:08     ` Like Xu
2023-04-07 15:43       ` Sean Christopherson
2023-02-14  5:07 ` [PATCH v4 06/12] KVM: x86/pmu: Make part of the Intel v2 PMU MSRs handling x86 generic Like Xu
2023-04-06 23:57   ` Sean Christopherson
2023-04-07  1:39   ` Sean Christopherson
2023-02-14  5:07 ` [PATCH v4 07/12] KVM: x86/cpuid: Use fast return for cpuid "0xa" leaf when !enable_pmu Like Xu
2023-04-06 23:59   ` Sean Christopherson
2023-02-14  5:07 ` Like Xu [this message]
2023-04-07  0:06   ` [PATCH v4 08/12] KVM: x86/pmu: Disable vPMU if the minimum num of counters isn't met Sean Christopherson
2023-04-07  0:23     ` Sean Christopherson
2023-02-14  5:07 ` [PATCH v4 09/12] KVM: x86/pmu: Forget PERFCTR_CORE if the min " Like Xu
2023-04-07  0:32   ` Sean Christopherson
2023-02-14  5:07 ` [PATCH v4 10/12] KVM: x86/cpuid: Add X86_FEATURE_PERFMON_V2 as a scattered flag Like Xu
2023-04-07  0:41   ` Sean Christopherson
2023-02-14  5:07 ` [PATCH v4 11/12] KVM: x86/svm/pmu: Add AMD PerfMonV2 support Like Xu
2023-04-07  1:35   ` Sean Christopherson
2023-04-07  7:08     ` Like Xu
2023-04-07 14:44       ` Sean Christopherson
2023-04-10 11:34         ` Like Xu
2023-02-14  5:07 ` [PATCH v4 12/12] KVM: x86/cpuid: Add AMD CPUID ExtPerfMonAndDbg leaf 0x80000022 Like Xu
2023-04-07  1:50   ` Sean Christopherson
2023-04-07  7:19     ` Like Xu
2023-04-07  2:02 ` [PATCH v4 00/12] KVM: x86: Add AMD Guest PerfMonV2 PMU support Sean Christopherson
2023-04-07  7:28   ` Like Xu

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