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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 8/9] KVM: VMX: Drop a redundant pmu->global_ctrl check when processing pebs_enable
Date: Fri,  8 May 2026 16:13:52 -0700	[thread overview]
Message-ID: <20260508231353.406465-9-seanjc@google.com> (raw)
In-Reply-To: <20260508231353.406465-1-seanjc@google.com>

Drop a redundant check that a PMC is globally enabled when looking for
PEBS counters that are cross-mapped between the guest and the host.  The
for-loop explicitly iterates over pmu->global_ctrl, and since PEBS requires
PMU v2+, kvm_pmu_has_perf_global_ctrl() must be true, and thus
pmc_is_globally_enabled() is simply checking that the bit is set in
pmu->global_ctrl.

No functional change intended.

Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/vmx/pmu_intel.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx/pmu_intel.c b/arch/x86/kvm/vmx/pmu_intel.c
index e65adb3dc066..659fe097b904 100644
--- a/arch/x86/kvm/vmx/pmu_intel.c
+++ b/arch/x86/kvm/vmx/pmu_intel.c
@@ -752,8 +752,7 @@ u64 intel_pmu_get_cross_mapped_mask(struct kvm_pmu *pmu)
 	host_cross_mapped_mask = 0;
 
 	kvm_for_each_pmc(pmu, pmc, bit, (unsigned long *)&pmu->global_ctrl) {
-		if (!pmc_is_locally_enabled(pmc) ||
-		    !pmc_is_globally_enabled(pmc) || !pmc->perf_event)
+		if (!pmc_is_locally_enabled(pmc) || !pmc->perf_event)
 			continue;
 
 		/*
-- 
2.54.0.563.g4f69b47b94-goog


  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 ` [PATCH v3 7/9] perf/x86/intel: KVM: Handle cross-mapped PEBS PMCs entirely within KVM Sean Christopherson
2026-05-12  4:59   ` Mi, Dapeng
2026-05-08 23:13 ` Sean Christopherson [this message]
2026-05-12  5:00   ` [PATCH v3 8/9] KVM: VMX: Drop a redundant pmu->global_ctrl check when processing pebs_enable 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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