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| author |   Oliver Upton <oliver.upton@linux.dev> | 2025-03-05 12:26:38 -0800 |
|---|---|---|
| committer | Oliver Upton <oliver.upton@linux.dev> | 2025-03-11 12:54:29 -0700 |
| commit | 1e7dcbfa4b7cddfbe1cde6067d135f5452692256 (patch) | |
| tree | 4043a2c41c7037f10a11899deb4e891db259765f | |
| parent | KVM: arm64: Advertise PMUv3 if IMPDEF traps are present (diff) | |
| download | wireguard-linux-1e7dcbfa4b7cddfbe1cde6067d135f5452692256.tar.xz wireguard-linux-1e7dcbfa4b7cddfbe1cde6067d135f5452692256.zip | |
KVM: arm64: Remap PMUv3 events onto hardware
Map PMUv3 event IDs onto hardware, if the driver exposes such a helper.
This is expected to be quite rare, and only useful for non-PMUv3 hardware.
Tested-by: Janne Grunau <j@jannau.net>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250305202641.428114-12-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
| -rw-r--r-- | arch/arm64/kvm/pmu-emul.c | 25 | ||||
| -rw-r--r-- | include/linux/perf/arm_pmu.h | 4 |
2 files changed, 28 insertions, 1 deletions
diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index 38d9490c17fd..5f4e9be8aa8b 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -677,6 +677,20 @@ static bool kvm_pmc_counts_at_el2(struct kvm_pmc *pmc) return kvm_pmc_read_evtreg(pmc) & ARMV8_PMU_INCLUDE_EL2; } +static int kvm_map_pmu_event(struct kvm *kvm, unsigned int eventsel) +{ + struct arm_pmu *pmu = kvm->arch.arm_pmu; + + /* + * The CPU PMU likely isn't PMUv3; let the driver provide a mapping + * for the guest's PMUv3 event ID. + */ + if (unlikely(pmu->map_pmuv3_event)) + return pmu->map_pmuv3_event(eventsel); + + return eventsel; +} + /** * kvm_pmu_create_perf_event - create a perf event for a counter * @pmc: Counter context @@ -687,7 +701,8 @@ static void kvm_pmu_create_perf_event(struct kvm_pmc *pmc) struct arm_pmu *arm_pmu = vcpu->kvm->arch.arm_pmu; struct perf_event *event; struct perf_event_attr attr; - u64 eventsel, evtreg; + int eventsel; + u64 evtreg; evtreg = kvm_pmc_read_evtreg(pmc); @@ -713,6 +728,14 @@ static void kvm_pmu_create_perf_event(struct kvm_pmc *pmc) !test_bit(eventsel, vcpu->kvm->arch.pmu_filter)) return; + /* + * Don't create an event if we're running on hardware that requires + * PMUv3 event translation and we couldn't find a valid mapping. + */ + eventsel = kvm_map_pmu_event(vcpu->kvm, eventsel); + if (eventsel < 0) + return; + memset(&attr, 0, sizeof(struct perf_event_attr)); attr.type = arm_pmu->pmu.type; attr.size = sizeof(attr); diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h index 4b5b83677e3f..7ce6dea5bfa9 100644 --- a/include/linux/perf/arm_pmu.h +++ b/include/linux/perf/arm_pmu.h @@ -100,6 +100,10 @@ struct arm_pmu { void (*stop)(struct arm_pmu *); void (*reset)(void *); int (*map_event)(struct perf_event *event); + /* + * Called by KVM to map the PMUv3 event space onto non-PMUv3 hardware. + */ + int (*map_pmuv3_event)(unsigned int eventsel); DECLARE_BITMAP(cntr_mask, ARMPMU_MAX_HWEVENTS); bool secure_access; /* 32-bit ARM only */ #define ARMV8_PMUV3_MAX_COMMON_EVENTS 0x40 |