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| author | Julien Thierry <julien.thierry@arm.com> | 2020-09-24 12:07:04 +0100 |
|---|---|---|
| committer | Will Deacon <will@kernel.org> | 2020-09-28 19:00:17 +0100 |
| commit | 95e92e45a454a10a8114294d0f7aec930fb85891 (patch) | |
| tree | 637e482d475bfb14a736e4500be69bea35cc728b | |
| parent | 05ab72813340d11205556c0d1bc08e6857a3856c (diff) | |
| download | linux-95e92e45a454a10a8114294d0f7aec930fb85891.tar.gz linux-95e92e45a454a10a8114294d0f7aec930fb85891.tar.bz2 linux-95e92e45a454a10a8114294d0f7aec930fb85891.zip | |
KVM: arm64: pmu: Make overflow handler NMI safe
kvm_vcpu_kick() is not NMI safe. When the overflow handler is called from
NMI context, defer waking the vcpu to an irq_work queue.
A vcpu can be freed while it's not running by kvm_destroy_vm(). Prevent
running the irq_work for a non-existent vcpu by calling irq_work_sync() on
the PMU destroy path.
[Alexandru E.: Added irq_work_sync()]
Signed-off-by: Julien Thierry <julien.thierry@arm.com>
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Tested-by: Sumit Garg <sumit.garg@linaro.org> (Developerbox)
Cc: Julien Thierry <julien.thierry.kdev@gmail.com>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: James Morse <james.morse@arm.com>
Cc: Suzuki K Pouloze <suzuki.poulose@arm.com>
Cc: kvm@vger.kernel.org
Cc: kvmarm@lists.cs.columbia.edu
Link: https://lore.kernel.org/r/20200924110706.254996-6-alexandru.elisei@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
| -rw-r--r-- | arch/arm64/kvm/pmu-emul.c | 26 | ||||
| -rw-r--r-- | include/kvm/arm_pmu.h | 1 |
2 files changed, 26 insertions, 1 deletions
diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index f0d0312c0a55..81916e360b1e 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -269,6 +269,7 @@ void kvm_pmu_vcpu_destroy(struct kvm_vcpu *vcpu) for (i = 0; i < ARMV8_PMU_MAX_COUNTERS; i++) kvm_pmu_release_perf_event(&pmu->pmc[i]); + irq_work_sync(&vcpu->arch.pmu.overflow_work); } u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu) @@ -434,6 +435,22 @@ void kvm_pmu_sync_hwstate(struct kvm_vcpu *vcpu) } /** + * When perf interrupt is an NMI, we cannot safely notify the vcpu corresponding + * to the event. + * This is why we need a callback to do it once outside of the NMI context. + */ +static void kvm_pmu_perf_overflow_notify_vcpu(struct irq_work *work) +{ + struct kvm_vcpu *vcpu; + struct kvm_pmu *pmu; + + pmu = container_of(work, struct kvm_pmu, overflow_work); + vcpu = kvm_pmc_to_vcpu(pmu->pmc); + + kvm_vcpu_kick(vcpu); +} + +/** * When the perf event overflows, set the overflow status and inform the vcpu. */ static void kvm_pmu_perf_overflow(struct perf_event *perf_event, @@ -465,7 +482,11 @@ static void kvm_pmu_perf_overflow(struct perf_event *perf_event, if (kvm_pmu_overflow_status(vcpu)) { kvm_make_request(KVM_REQ_IRQ_PENDING, vcpu); - kvm_vcpu_kick(vcpu); + + if (!in_nmi()) + kvm_vcpu_kick(vcpu); + else + irq_work_queue(&vcpu->arch.pmu.overflow_work); } cpu_pmu->pmu.start(perf_event, PERF_EF_RELOAD); @@ -764,6 +785,9 @@ static int kvm_arm_pmu_v3_init(struct kvm_vcpu *vcpu) return ret; } + init_irq_work(&vcpu->arch.pmu.overflow_work, + kvm_pmu_perf_overflow_notify_vcpu); + vcpu->arch.pmu.created = true; return 0; } diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h index 6db030439e29..dbf4f08d42e5 100644 --- a/include/kvm/arm_pmu.h +++ b/include/kvm/arm_pmu.h @@ -27,6 +27,7 @@ struct kvm_pmu { bool ready; bool created; bool irq_level; + struct irq_work overflow_work; }; #define kvm_arm_pmu_v3_ready(v) ((v)->arch.pmu.ready) |