From: Sean Christopherson <seanjc@google.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Sean Christopherson <seanjc@google.com>,
Paolo Bonzini <pbonzini@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
James Clark <james.clark@linaro.org>,
linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, Jim Mattson <jmattson@google.com>,
Mingwei Zhang <mizhang@google.com>,
Stephane Eranian <eranian@google.com>,
Dapeng Mi <dapeng1.mi@linux.intel.com>
Subject: [PATCH v3 7/9] perf/x86/intel: KVM: Handle cross-mapped PEBS PMCs entirely within KVM
Date: Fri, 8 May 2026 16:13:51 -0700 [thread overview]
Message-ID: <20260508231353.406465-8-seanjc@google.com> (raw)
In-Reply-To: <20260508231353.406465-1-seanjc@google.com>
Now that perf operates on a KVM-provided snapshot of PMU state, handled
cross-mapped PEBS counters entirely in KVM by clearing unusable counters
from the to-be-enabled mask instead of foisting the work on perf.
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/events/intel/core.c | 8 --------
arch/x86/include/asm/perf_event.h | 1 -
arch/x86/kvm/vmx/vmx.c | 10 ++++++++--
3 files changed, 8 insertions(+), 11 deletions(-)
diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index e9acfc3f3a82..8f6be0cc4c4b 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -5053,14 +5053,6 @@ static struct perf_guest_switch_msr *intel_guest_get_msrs(int *nr,
~cpuc->intel_ctrl_exclude_guest_mask &
cpuc->intel_ctrl_exclude_host_mask;
- /*
- * Disable counters where the guest PMC is different than the host PMC
- * being used on behalf of the guest, as the PEBS record includes
- * PERF_GLOBAL_STATUS, i.e. the guest will see overflow status for the
- * wrong counter(s).
- */
- guest_pebs_mask &= ~guest_pebs->cross_mapped_mask;
-
/*
* FIXME: Allow guest and host usage of PEBS events to co-exist instead
* of disabling guest PEBS entirely if the host is using PEBS.
diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index bc7e48f6f4a8..19f874a79ab0 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -790,7 +790,6 @@ struct x86_guest_pebs {
u64 enable;
u64 ds_area;
u64 data_cfg;
- u64 cross_mapped_mask;
};
#if defined(CONFIG_PERF_EVENTS) && defined(CONFIG_CPU_SUP_INTEL)
extern struct perf_guest_switch_msr *perf_guest_get_msrs(int *nr,
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 9f0a028cf10b..fbe3ce5f5a51 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -7319,8 +7319,14 @@ static void atomic_switch_perf_msrs(struct vcpu_vmx *vmx)
.data_cfg = pmu->pebs_data_cfg,
};
- if (pmu->pebs_enable & pmu->global_ctrl)
- guest_pebs.cross_mapped_mask = intel_pmu_get_cross_mapped_mask(pmu);
+ /*
+ * Disable counters where the guest PMC is different than the host PMC
+ * being used on behalf of the guest, as the PEBS record includes
+ * PERF_GLOBAL_STATUS, i.e. the guest will see overflow status for the
+ * wrong counter(s).
+ */
+ if (guest_pebs.enable & pmu->global_ctrl)
+ guest_pebs.enable &= ~intel_pmu_get_cross_mapped_mask(pmu);
/* Note, nr_msrs may be garbage if perf_guest_get_msrs() returns NULL. */
msrs = perf_guest_get_msrs(&nr_msrs, &guest_pebs);
--
2.54.0.563.g4f69b47b94-goog
next prev parent reply other threads:[~2026-05-08 23:14 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-08 23:13 [PATCH v3 0/9] perf/x86: Don't write PEBS_ENABLED on KVM transitions Sean Christopherson
2026-05-08 23:13 ` [PATCH v3 1/9] perf/x86/intel: Ensure guest PEBS path doesn't set unwanted PERF_GLOBAL_CTRL bits Sean Christopherson
2026-05-12 4:53 ` Mi, Dapeng
2026-05-08 23:13 ` [PATCH v3 2/9] perf/x86/intel: Don't write PEBS_ENABLED on host<=>guest xfers if CPU has isolation Sean Christopherson
2026-05-12 4:53 ` Mi, Dapeng
2026-05-08 23:13 ` [PATCH v3 3/9] perf/x86/intel: Don't context switch DS_AREA (and PEBS config) if PEBS is unused Sean Christopherson
2026-05-08 23:13 ` [PATCH v3 4/9] perf/x86/intel: Make @data a mandatory param for intel_guest_get_msrs() Sean Christopherson
2026-05-12 12:39 ` Jim Mattson
2026-05-08 23:13 ` [PATCH v3 5/9] perf/x86/intel: Invert names of intel_ctrl_{guest,host}_mask Sean Christopherson
2026-05-12 4:58 ` Mi, Dapeng
2026-05-08 23:13 ` [PATCH v3 6/9] perf/x86: KVM: Have perf define a dedicated struct for getting guest PEBS data Sean Christopherson
2026-05-08 23:13 ` Sean Christopherson [this message]
2026-05-12 4:59 ` [PATCH v3 7/9] perf/x86/intel: KVM: Handle cross-mapped PEBS PMCs entirely within KVM Mi, Dapeng
2026-05-08 23:13 ` [PATCH v3 8/9] KVM: VMX: Drop a redundant pmu->global_ctrl check when processing pebs_enable Sean Christopherson
2026-05-12 5:00 ` Mi, Dapeng
2026-05-08 23:13 ` [PATCH v3 9/9] KVM: VMX: Only tell perf to enable PEBS counters for fully enabled PMCs Sean Christopherson
2026-05-12 5:01 ` Mi, Dapeng
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