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: linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
kvm@vger.kernel.org, Mingwei Zhang <mizhang@google.com>,
Jim Mattson <jmattson@google.com>
Subject: [PATCH 2/3] perf/x86/intel: Expose existence of callback support to KVM
Date: Wed, 6 Mar 2024 17:13:43 -0800 [thread overview]
Message-ID: <20240307011344.835640-3-seanjc@google.com> (raw)
In-Reply-To: <20240307011344.835640-1-seanjc@google.com>
Add a "has_callstack" field to the x86_pmu_lbr structure used to pass
information to KVM, and set it accordingly in x86_perf_get_lbr(). KVM
will use has_callstack to avoid trying to create perf LBR events with
PERF_SAMPLE_BRANCH_CALL_STACK on CPUs that don't support callstacks.
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
arch/x86/events/intel/lbr.c | 1 +
arch/x86/include/asm/perf_event.h | 1 +
2 files changed, 2 insertions(+)
diff --git a/arch/x86/events/intel/lbr.c b/arch/x86/events/intel/lbr.c
index 78cd5084104e..4367aa77cb8d 100644
--- a/arch/x86/events/intel/lbr.c
+++ b/arch/x86/events/intel/lbr.c
@@ -1693,6 +1693,7 @@ void x86_perf_get_lbr(struct x86_pmu_lbr *lbr)
lbr->from = x86_pmu.lbr_from;
lbr->to = x86_pmu.lbr_to;
lbr->info = x86_pmu.lbr_info;
+ lbr->has_callstack = x86_pmu_has_lbr_callstack();
}
EXPORT_SYMBOL_GPL(x86_perf_get_lbr);
diff --git a/arch/x86/include/asm/perf_event.h b/arch/x86/include/asm/perf_event.h
index 3736b8a46c04..7f1e17250546 100644
--- a/arch/x86/include/asm/perf_event.h
+++ b/arch/x86/include/asm/perf_event.h
@@ -555,6 +555,7 @@ struct x86_pmu_lbr {
unsigned int from;
unsigned int to;
unsigned int info;
+ bool has_callstack;
};
extern void perf_get_x86_pmu_capability(struct x86_pmu_capability *cap);
--
2.44.0.278.ge034bb2e1d-goog
next prev parent reply other threads:[~2024-03-07 1:13 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-07 1:13 [PATCH 0/3] KVM: VMX: Disable LBRs if CPU doesn't have callstacks Sean Christopherson
2024-03-07 1:13 ` [PATCH 1/3] KVM: VMX: Snapshot LBR capabilities during module initialization Sean Christopherson
2024-03-18 22:50 ` Mingwei Zhang
2024-03-07 1:13 ` Sean Christopherson [this message]
2024-03-18 22:50 ` [PATCH 2/3] perf/x86/intel: Expose existence of callback support to KVM Mingwei Zhang
2024-03-07 1:13 ` [PATCH 3/3] KVM: VMX: Disable LBR virtualization if the CPU doesn't support LBR callstacks Sean Christopherson
2024-03-18 22:51 ` Mingwei Zhang
2024-04-09 2:01 ` [PATCH 0/3] KVM: VMX: Disable LBRs if CPU doesn't have callstacks Sean Christopherson
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