Re: [PATCH v4 06/14] KVM: arm64: Set protected VM traps based on its view of feature registers

[Quentin Perret <qperret@google.com>]

On Monday 02 Dec 2024 at 15:47:33 (+0000), Fuad Tabba wrote:
>  static void pvm_init_traps_hcr(struct kvm_vcpu *vcpu)
>  {
> -	const u64 id_aa64pfr0 = pvm_read_id_reg(vcpu, SYS_ID_AA64PFR0_EL1);
> -	const u64 id_aa64pfr1 = pvm_read_id_reg(vcpu, SYS_ID_AA64PFR1_EL1);
> -	const u64 id_aa64mmfr1 = pvm_read_id_reg(vcpu, SYS_ID_AA64MMFR1_EL1);
> +	struct kvm *kvm = vcpu->kvm;
>  	u64 val = vcpu->arch.hcr_el2;
>  
>  	/* No support for AArch32. */
> @@ -70,25 +68,20 @@ static void pvm_init_traps_hcr(struct kvm_vcpu *vcpu)
>  	 */
>  	val |= HCR_TACR | HCR_TIDCP | HCR_TID3 | HCR_TID1;
>  
> -	/* Trap RAS unless all current versions are supported */
> -	if (FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_EL1_RAS), id_aa64pfr0) <
> -	    ID_AA64PFR0_EL1_RAS_V1P1) {
> +	if (!kvm_has_feat(kvm, ID_AA64PFR0_EL1, RAS, IMP)) {

I'm admittedly getting a bit lost in the kvm_has_feat() macro maze, but
should this be:

	if (!kvm_has_feat(kvm, ID_AA64PFR0_EL1, RAS, V1P1))

to replicate the existing check?

>  		val |= HCR_TERR | HCR_TEA;
>  		val &= ~(HCR_FIEN);
>  	}