diff options
| author | Alexandru Elisei <alexandru.elisei@arm.com> | 2021-04-09 16:21:54 +0100 |
|---|---|---|
| committer | Marc Zyngier <maz@kernel.org> | 2021-04-11 09:46:13 +0100 |
| commit | 96f4f6809beec1bb2338e1aeac408e6a733f8135 (patch) | |
| tree | ceac3f5e3722d7006c8bf2500621617c7e97b55c /arch/arm64/kvm | |
| parent | 13611bc80d3da162aaf32b01ceffc804e027d406 (diff) | |
KVM: arm64: Don't advertise FEAT_SPE to guests
Even though KVM sets up MDCR_EL2 to trap accesses to the SPE buffer and
sampling control registers and to inject an undefined exception, the
presence of FEAT_SPE is still advertised in the ID_AA64DFR0_EL1 register,
if the hardware supports it. Getting an undefined exception when accessing
a register usually happens for a hardware feature which is not implemented,
and indeed this is how PMU emulation is handled when the virtual machine
has been created without the KVM_ARM_VCPU_PMU_V3 feature. Let's be
consistent and never advertise FEAT_SPE, because KVM doesn't have support
for emulating it yet.
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210409152154.198566-3-alexandru.elisei@arm.com
Diffstat (limited to 'arch/arm64/kvm')
| -rw-r--r-- | arch/arm64/kvm/sys_regs.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 402cd11aa4fc..61ee9bfb8826 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -1063,6 +1063,8 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu, val = cpuid_feature_cap_perfmon_field(val, ID_AA64DFR0_PMUVER_SHIFT, kvm_vcpu_has_pmu(vcpu) ? ID_AA64DFR0_PMUVER_8_4 : 0); + /* Hide SPE from guests */ + val &= ~FEATURE(ID_AA64DFR0_PMSVER); break; case SYS_ID_DFR0_EL1: /* Limit guests to PMUv3 for ARMv8.4 */ |