KVM: arm64: Fix AArch32 PMUv3 capping

We shouldn't expose *any* PMU capability when no PMU has been
configured for this VM.

Reviewed-by: Eric Auger <eric.auger@redhat.com>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 0c08324..ce08d28 100644 (file)
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1048,8 +1048,8 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu,
        } else if (id == SYS_ID_DFR0_EL1) {
                /* Limit guests to PMUv3 for ARMv8.1 */
                val = cpuid_feature_cap_perfmon_field(val,
-                                               ID_DFR0_PERFMON_SHIFT,
-                                               ID_DFR0_PERFMON_8_1);
+                                                     ID_DFR0_PERFMON_SHIFT,
+                                                     kvm_vcpu_has_pmu(vcpu) ? ID_DFR0_PERFMON_8_1 : 0);
        }
 
        return val;