diff mbox series

[v3,1/4] KVM: arm64: PMU: Disallow vPMU on non-uniform PMUVer

Message ID 20230819043947.4100985-2-reijiw@google.com (mailing list archive)
State New, archived
Headers show
Series KVM: arm64: PMU: Fix PMUver related handling of vPMU support | expand

Commit Message

Reiji Watanabe Aug. 19, 2023, 4:39 a.m. UTC 
Disallow userspace from configuring vPMU for guests on systems
where the PMUVer is not uniform across all PEs.
KVM has not been advertising PMUv3 to the guests with vPMU on
such systems anyway, and such systems would be extremely
uncommon and unlikely to even use KVM.

Signed-off-by: Reiji Watanabe <reijiw@google.com>
---
 arch/arm64/kvm/pmu-emul.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index 560650972478..689bbd88fd69 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -14,6 +14,7 @@ 
 #include <asm/kvm_emulate.h>
 #include <kvm/arm_pmu.h>
 #include <kvm/arm_vgic.h>
+#include <asm/arm_pmuv3.h>
 
 #define PERF_ATTR_CFG1_COUNTER_64BIT	BIT(0)
 
@@ -672,8 +673,11 @@  void kvm_host_pmu_init(struct arm_pmu *pmu)
 {
 	struct arm_pmu_entry *entry;
 
-	if (pmu->pmuver == ID_AA64DFR0_EL1_PMUVer_NI ||
-	    pmu->pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF)
+	/*
+	 * Check the sanitised PMU version for the system, as KVM does not
+	 * support implementations where PMUv3 exists on a subset of CPUs.
+	 */
+	if (!pmuv3_implemented(kvm_arm_pmu_get_pmuver_limit()))
 		return;
 
 	mutex_lock(&arm_pmus_lock);