Kernel KVM virtualization development
 help / color / mirror / Atom feed
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


  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20260508231353.406465-8-seanjc@google.com \
    --to=seanjc@google.com \
    --cc=acme@kernel.org \
    --cc=adrian.hunter@intel.com \
    --cc=alexander.shishkin@linux.intel.com \
    --cc=dapeng1.mi@linux.intel.com \
    --cc=eranian@google.com \
    --cc=irogers@google.com \
    --cc=james.clark@linaro.org \
    --cc=jmattson@google.com \
    --cc=jolsa@kernel.org \
    --cc=kvm@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-perf-users@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    --cc=mingo@redhat.com \
    --cc=mizhang@google.com \
    --cc=namhyung@kernel.org \
    --cc=pbonzini@redhat.com \
    --cc=peterz@infradead.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox