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KVM: arm64: Refuse to run VCPU if the PMU doesn't match the physical CPU

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Userspace can assign a PMU to a VCPU with the KVM_ARM_VCPU_PMU_V3_SET_PMU
device ioctl. If the VCPU is scheduled on a physical CPU which has a
different PMU, the perf events needed to emulate a guest PMU won't be
scheduled in and the guest performance counters will stop counting. Treat
it as an userspace error and refuse to run the VCPU in this situation.

Suggested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220127161759.53553-7-alexandru.elisei@arm.com
This commit is contained in:
Alexandru Elisei
2022-01-27 16:17:59 +00:00
committed by Marc Zyngier
parent 6ee7fca2a4
commit 583cda1b0e
5 changed files with 38 additions and 1 deletions
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3
arch/arm64/include/uapi/asm/kvm.h
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@@ -414,6 +414,9 @@ struct kvm_arm_copy_mte_tags {
#define KVM_PSCI_RET_INVAL PSCI_RET_INVALID_PARAMS
#define KVM_PSCI_RET_DENIED PSCI_RET_DENIED
/* run->fail_entry.hardware_entry_failure_reason codes. */
#define KVM_EXIT_FAIL_ENTRY_CPU_UNSUPPORTED (1ULL << 0)
#endif
#endif /* __ARM_KVM_H__ */