[PATCH v2 2/2] KVM: arm64: Correctly identify executable PTEs at stage-2

[Oliver Upton <oupton@kernel.org>]

KVM invalidates the I-cache before installing an executable PTE on
implementations without DIC. Unfortunately, support for FEAT_XNX
broke this check as KVM_PTE_LEAF_ATTR_HI_S2_XN was expanded to a
bitfield.

Fix it by reusing kvm_pgtable_stage2_pte_prot() and testing the abstract
permission bits instead.

Fixes: 2608563b466b ("KVM: arm64: Add support for FEAT_XNX stage-2 permissions")
Reported-by: Sashiko (gemini/gemini-3.1-pro-preview)
Signed-off-by: Oliver Upton <oupton@kernel.org>
---
 arch/arm64/kvm/hyp/pgtable.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 0c1defa5fb0f..91a7dfad6686 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -925,7 +925,9 @@ static bool stage2_pte_cacheable(struct kvm_pgtable *pgt, kvm_pte_t pte)
 
 static bool stage2_pte_executable(kvm_pte_t pte)
 {
-	return kvm_pte_valid(pte) && !(pte & KVM_PTE_LEAF_ATTR_HI_S2_XN);
+	enum kvm_pgtable_prot prot = kvm_pgtable_stage2_pte_prot(pte);
+
+	return prot & (KVM_PGTABLE_PROT_UX | KVM_PGTABLE_PROT_PX);
 }
 
 static u64 stage2_map_walker_phys_addr(const struct kvm_pgtable_visit_ctx *ctx,
-- 
2.47.3