From: "Mi, Dapeng" <dapeng1.mi@linux.intel.com>
To: Zide Chen <zide.chen@intel.com>,
Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Peter Zijlstra <peterz@infradead.org>
Cc: kvm@vger.kernel.org, Andi Kleen <ak@linux.intel.com>,
Jim Mattson <jmattson@google.com>,
Stephane Eranian <eranian@google.com>,
linux-kernel@vger.kernel.org, Mingwei Zhang <mizhang@google.com>,
Das Sandipan <Sandipan.Das@amd.com>,
Shukla Manali <Manali.Shukla@amd.com>,
Xudong Hao <xudong.hao@intel.com>
Subject: Re: [PATCH v2 04/16] KVM: x86/pmu: Gate BUFFER_OVF reserved bit on guest DS
Date: Tue, 1 Sep 2026 10:30:58 +0800 [thread overview]
Message-ID: <253df5b9-e13a-4d19-aa46-d6432384985e@linux.intel.com> (raw)
In-Reply-To: <20260827223755.143247-5-zide.chen@intel.com>
Reviewed-by: Dapeng Mi <dapeng1.mi@linux.intel.com>
On 8/28/2026 6:37 AM, Zide Chen wrote:
> global_status_rsvd unconditionally clears GLOBAL_STATUS_BUFFER_OVF
> (bit 62), even when the guest does not have X86_FEATURE_DS feature.
> Clear it only when guest_cpu_cap_has(vcpu, X86_FEATURE_DS), matching
> hardware behavior.
>
> Fixes: f5132b01386b ("KVM: Expose a version 2 architectural PMU to a guests")
> Signed-off-by: Zide Chen <zide.chen@intel.com>
> ---
> v2: new patch.
> ---
> arch/x86/kvm/vmx/pmu_intel.c | 12 ++++++++++--
> 1 file changed, 10 insertions(+), 2 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
> index 11c9161dc853..9fdae437e569 100644
> --- a/arch/x86/kvm/vmx/pmu_intel.c
> +++ b/arch/x86/kvm/vmx/pmu_intel.c
> @@ -576,8 +576,16 @@ static void intel_pmu_refresh(struct kvm_vcpu *vcpu)
> ((BIT_ULL(pmu->nr_arch_fixed_counters) - 1) << KVM_FIXED_PMC_BASE_IDX));
> pmu->global_ctrl_rsvd = counter_rsvd;
>
> - pmu->global_status_rsvd = pmu->global_ctrl_rsvd
> - & ~(GLOBAL_STATUS_BUFFER_OVF | GLOBAL_STATUS_COND_CHG);
> + /*
> + * Layout of bits 48:0 in IA32_PERF_GLOBAL_CTRL is identical to
> + * IA32_PERF_GLOBAL_STATUS, but IA32_PERF_GLOBAL_STATUS has additional
> + * bits.
> + */
> + pmu->global_status_rsvd = pmu->global_ctrl_rsvd;
> + if (guest_cpu_cap_has(vcpu, X86_FEATURE_DS))
> + pmu->global_status_rsvd &= ~GLOBAL_STATUS_BUFFER_OVF;
> + pmu->global_status_rsvd &= ~GLOBAL_STATUS_COND_CHG;
> +
> if (vmx_pt_mode_is_host_guest())
> pmu->global_status_rsvd &= ~GLOBAL_STATUS_TRACE_TOPAPMI;
>
next prev parent reply other threads:[~2026-09-01 2:31 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-27 22:37 [PATCH] KVM: x86/pmu: Add mediated vPMU PerfMon v5 support Zide Chen
2026-08-27 22:37 ` [PATCH v2 01/16] KVM: x86/pmu: Remove redundant Perf Global Status MSR bit definitions Zide Chen
2026-09-01 2:07 ` Mi, Dapeng
2026-08-27 22:37 ` [PATCH v2 02/16] KVM: x86/pmu: Rename all_valid_pmc_idx to pmc_exists Zide Chen
2026-09-01 2:09 ` Mi, Dapeng
2026-08-27 22:37 ` [PATCH v2 03/16] KVM: x86/pmu: Rename reserved_bits to eventsel_rsvd in kvm_pmu Zide Chen
2026-09-01 2:17 ` Mi, Dapeng
2026-08-27 22:37 ` [PATCH v2 04/16] KVM: x86/pmu: Gate BUFFER_OVF reserved bit on guest DS Zide Chen
2026-09-01 2:30 ` Mi, Dapeng [this message]
2026-08-27 22:37 ` [PATCH v2 05/16] KVM: x86/pmu: Add PMC bitmap accessor helpers Zide Chen
2026-09-01 2:43 ` Mi, Dapeng
2026-08-27 22:37 ` [PATCH v2 06/16] KVM: x86/pmu: Drop nr_arch_{gp,fixed}_counters from kvm_pmu Zide Chen
2026-09-01 3:07 ` Mi, Dapeng
2026-08-27 22:37 ` [PATCH v2 07/16] KVM: x86/pmu: Expose kvm_host_pmu to vendor modules Zide Chen
2026-09-01 3:08 ` Mi, Dapeng
2026-08-27 22:37 ` [PATCH v2 08/16] perf/x86: Plumb counter bitmap from x86_pmu to x86_pmu_cap Zide Chen
2026-08-27 22:37 ` [PATCH v2 09/16] KVM: x86/pmu: Switch to bitmask-based KVM PMU capabilities Zide Chen
2026-09-01 3:32 ` Mi, Dapeng
2026-08-27 22:37 ` [PATCH v2 10/16] perf/x86: Remove num_counters_{gp,fixed} from x86_pmu_capability Zide Chen
2026-08-27 22:37 ` [PATCH v2 11/16] KVM: x86/pmu: Emulate the GLOBAL_STATUS_SET and GLOBAL_INUSE MSRs Zide Chen
2026-09-01 6:45 ` Mi, Dapeng
2026-09-01 14:20 ` Chen, Zide
2026-09-02 0:44 ` Mi, Dapeng
2026-08-27 22:37 ` [PATCH v2 12/16] KVM: x86/pmu: Populate CPUID.0AH:ECX fixed-counter bitmap Zide Chen
2026-09-01 6:50 ` Mi, Dapeng
2026-08-27 22:37 ` [PATCH v2 13/16] KVM: x86/pmu: Factor out fixed counter control bit calculation Zide Chen
2026-09-01 6:57 ` Mi, Dapeng
2026-08-27 22:37 ` [PATCH v2 14/16] KVM: x86/pmu: Ignore AnyThread bit if CPUID.0AH:EDX[15] is set Zide Chen
2026-09-01 8:01 ` Mi, Dapeng
2026-08-27 22:37 ` [PATCH v2 15/16] KVM: x86/pmu: Advertise PerfMon version 5 on Intel hosts Zide Chen
2026-08-27 22:37 ` [PATCH v2 16/16] KVM: selftests: Support fixed counters bitmap in pmu_counters_test Zide Chen
2026-08-29 9:30 ` [PATCH] KVM: x86/pmu: Add mediated vPMU PerfMon v5 support Peter Zijlstra
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