[PATCH 2/6] KVM: arm64: Fix AArch32 PMUv3 capping

[Auger Eric]

Hi Marc,

On 1/14/21 11:56 AM, Marc Zyngier wrote:
> We shouldn't expose *any* PMU capability when no PMU has been
> configured for this VM.
> 
> Signed-off-by: Marc Zyngier <maz at kernel.org>
> ---
>  arch/arm64/kvm/sys_regs.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 0c0832472c4a..ce08d28ab15c 100644
> --- 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);
nit: Maybe you could use the same layout for SYS_ID_AA64DFR0_EL1
andremove cap there.

Reviewed-by: Eric Auger <eric.auger at redhat.com>

Eric



>  	}
>  
>  	return val;
>