[PATCH v5 3/8] KVM: arm64: Simplify masking out MTE in feature id reg

[Andrew Jones]

On Fri, Aug 27, 2021 at 11:16:04AM +0100, Fuad Tabba wrote:
> Simplify code for hiding MTE support in feature id register when
> MTE is not enabled/supported by KVM.
> 
> No functional change intended.
> 
> Signed-off-by: Fuad Tabba <tabba at google.com>
> ---
>  arch/arm64/kvm/sys_regs.c | 10 ++--------
>  1 file changed, 2 insertions(+), 8 deletions(-)
> 
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 1d46e185f31e..447acce9ca84 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -1077,14 +1077,8 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu,
>  		val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR0_CSV3), (u64)vcpu->kvm->arch.pfr0_csv3);
>  		break;
>  	case SYS_ID_AA64PFR1_EL1:
> -		val &= ~ARM64_FEATURE_MASK(ID_AA64PFR1_MTE);
> -		if (kvm_has_mte(vcpu->kvm)) {
> -			u64 pfr, mte;
> -
> -			pfr = read_sanitised_ftr_reg(SYS_ID_AA64PFR1_EL1);
> -			mte = cpuid_feature_extract_unsigned_field(pfr, ID_AA64PFR1_MTE_SHIFT);
> -			val |= FIELD_PREP(ARM64_FEATURE_MASK(ID_AA64PFR1_MTE), mte);
> -		}
> +		if (!kvm_has_mte(vcpu->kvm))
> +			val &= ~ARM64_FEATURE_MASK(ID_AA64PFR1_MTE);
>  		break;
>  	case SYS_ID_AA64ISAR1_EL1:
>  		if (!vcpu_has_ptrauth(vcpu))
> -- 
> 2.33.0.259.gc128427fd7-goog
>

Reviewed-by: Andrew Jones <drjones at redhat.com>