[PATCH 09/20] KVM: arm64: Convert HCR_EL2.RW to AS_RES1

[Fuad Tabba]

On Mon, 26 Jan 2026 at 12:17, Marc Zyngier <maz at kernel.org> wrote:
>
> Now that we have the AS_RES1 constraint, it becomes trivial to express
> the HCR_EL2.RW behaviour.
>
> Signed-off-by: Marc Zyngier <maz at kernel.org>

Reviewed-by: Fuad Tabba <tabba at google.com>

Cheers,
/fuad

> ---
>  arch/arm64/kvm/config.c | 15 +--------------
>  1 file changed, 1 insertion(+), 14 deletions(-)
>
> diff --git a/arch/arm64/kvm/config.c b/arch/arm64/kvm/config.c
> index 68ed5af2b4d53..39487182057a3 100644
> --- a/arch/arm64/kvm/config.c
> +++ b/arch/arm64/kvm/config.c
> @@ -389,19 +389,6 @@ static bool feat_vmid16(struct kvm *kvm)
>         return kvm_has_feat_enum(kvm, ID_AA64MMFR1_EL1, VMIDBits, 16);
>  }
>
> -static bool compute_hcr_rw(struct kvm *kvm, u64 *bits)
> -{
> -       /* This is purely academic: AArch32 and NV are mutually exclusive */
> -       if (bits) {
> -               if (kvm_has_feat(kvm, FEAT_AA32EL1))
> -                       *bits &= ~HCR_EL2_RW;
> -               else
> -                       *bits |= HCR_EL2_RW;
> -       }
> -
> -       return true;
> -}
> -
>  static bool compute_hcr_e2h(struct kvm *kvm, u64 *bits)
>  {
>         if (bits) {
> @@ -967,7 +954,7 @@ static const DECLARE_FEAT_MAP(hcrx_desc, __HCRX_EL2,
>
>  static const struct reg_bits_to_feat_map hcr_feat_map[] = {
>         NEEDS_FEAT(HCR_EL2_TID0, FEAT_AA32EL0),
> -       NEEDS_FEAT_FIXED(HCR_EL2_RW, compute_hcr_rw),
> +       NEEDS_FEAT_FLAG(HCR_EL2_RW, AS_RES1, FEAT_AA32EL1),
>         NEEDS_FEAT(HCR_EL2_HCD, not_feat_aa64el3),
>         NEEDS_FEAT(HCR_EL2_AMO          |
>                    HCR_EL2_BSU          |
> --
> 2.47.3
>