[PATCH v2 1/6] KVM: arm64: Fix EL2 S1 XN handling for hVHE setups

[Fuad Tabba]

Hi Marc,


On Wed, 10 Dec 2025 at 17:30, Marc Zyngier <maz at kernel.org> wrote:
>
> The current XN implementation is tied to the EL2 translation regime,
> and fall flat on its face with the EL2&0 one that is used for hVHE,
> as the permission bit for privileged execution is a different one.
>
> Fixes: 6537565fd9b7f ("KVM: arm64: Adjust EL2 stage-1 leaf AP bits when ARM64_KVM_HVHE is set")
> Signed-off-by: Marc Zyngier <maz at kernel.org>
> ---
>  arch/arm64/include/asm/kvm_pgtable.h | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/kvm_pgtable.h b/arch/arm64/include/asm/kvm_pgtable.h
> index fc02de43c68dd..be68b89692065 100644
> --- a/arch/arm64/include/asm/kvm_pgtable.h
> +++ b/arch/arm64/include/asm/kvm_pgtable.h
> @@ -87,7 +87,15 @@ typedef u64 kvm_pte_t;
>
>  #define KVM_PTE_LEAF_ATTR_HI_SW                GENMASK(58, 55)
>
> -#define KVM_PTE_LEAF_ATTR_HI_S1_XN     BIT(54)
> +#define __KVM_PTE_LEAF_ATTR_HI_S1_XN   BIT(54)
> +#define __KVM_PTE_LEAF_ATTR_HI_S1_UXN  BIT(54)
> +#define __KVM_PTE_LEAF_ATTR_HI_S1_PXN  BIT(53)
> +
> +#define KVM_PTE_LEAF_ATTR_HI_S1_XN                                     \
> +       ({ cpus_have_final_cap(ARM64_KVM_HVHE) ?                        \
> +                       (__KVM_PTE_LEAF_ATTR_HI_S1_UXN |                \
> +                        __KVM_PTE_LEAF_ATTR_HI_S1_PXN) :               \
> +                       __KVM_PTE_LEAF_ATTR_HI_S1_XN; })
>
>  #define KVM_PTE_LEAF_ATTR_HI_S2_XN     GENMASK(54, 53)

I was just wondering, is this patch really necessary, considering
patch 6/6 redos the whole thing and fixes the bug?

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

Cheers,
/fuad

> --
> 2.47.3
>