KVM: arm64: Check for PTE validity when checking for executable/cacheable

Don't just assume that the PTE is valid when checking whether it
describes an executable or cacheable mapping.

This makes sure that we don't issue CMOs for invalid mappings.

Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Fuad Tabba <tabba@google.com>
Acked-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20240423150538.2103045-8-tabba@google.com
Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 3fae5830f8d2c72f4ed4032cfd99fd285cbcb885..da54bb31291069f6be450b05aa20aff9cb471ba5 100644 (file)
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -907,12 +907,12 @@ static void stage2_unmap_put_pte(const struct kvm_pgtable_visit_ctx *ctx,
 static bool stage2_pte_cacheable(struct kvm_pgtable *pgt, kvm_pte_t pte)
 {
        u64 memattr = pte & KVM_PTE_LEAF_ATTR_LO_S2_MEMATTR;
-       return memattr == KVM_S2_MEMATTR(pgt, NORMAL);
+       return kvm_pte_valid(pte) && memattr == KVM_S2_MEMATTR(pgt, NORMAL);
 }
 
 static bool stage2_pte_executable(kvm_pte_t pte)
 {
-       return !(pte & KVM_PTE_LEAF_ATTR_HI_S2_XN);
+       return kvm_pte_valid(pte) && !(pte & KVM_PTE_LEAF_ATTR_HI_S2_XN);
 }
 
 static u64 stage2_map_walker_phys_addr(const struct kvm_pgtable_visit_ctx *ctx,
@@ -1363,7 +1363,7 @@ static int stage2_flush_walker(const struct kvm_pgtable_visit_ctx *ctx,
        struct kvm_pgtable *pgt = ctx->arg;
        struct kvm_pgtable_mm_ops *mm_ops = pgt->mm_ops;
 
-       if (!kvm_pte_valid(ctx->old) || !stage2_pte_cacheable(pgt, ctx->old))
+       if (!stage2_pte_cacheable(pgt, ctx->old))
                return 0;
 
        if (mm_ops->dcache_clean_inval_poc)