[PATCH 29/89] KVM: arm64: Check for PTE validity when checking for executable/cacheable

[Will Deacon]

From: Marc Zyngier <maz at kernel.org>

Don't blindly 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 at kernel.org>
Signed-off-by: Marc Zyngier <maz at kernel.org>
---
 arch/arm64/kvm/hyp/pgtable.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 1d300313009d..a6676fd14cf9 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -700,12 +700,12 @@ static void stage2_put_pte(kvm_pte_t *ptep, struct kvm_s2_mmu *mmu, u64 addr,
 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 bool stage2_leaf_mapping_allowed(u64 addr, u64 end, u32 level,
@@ -750,8 +750,7 @@ static int stage2_map_walker_try_leaf(u64 addr, u64 end, u32 level,
 	/* Perform CMOs before installation of the guest stage-2 PTE */
 	if (mm_ops->dcache_clean_inval_poc && stage2_pte_cacheable(pgt, new))
 		mm_ops->dcache_clean_inval_poc(kvm_pte_follow(new, mm_ops),
-						granule);
-
+					       granule);
 	if (mm_ops->icache_inval_pou && stage2_pte_executable(new))
 		mm_ops->icache_inval_pou(kvm_pte_follow(new, mm_ops), granule);
 
@@ -1148,7 +1147,7 @@ static int stage2_flush_walker(u64 addr, u64 end, u32 level, kvm_pte_t *ptep,
 	struct kvm_pgtable_mm_ops *mm_ops = pgt->mm_ops;
 	kvm_pte_t pte = *ptep;
 
-	if (!kvm_pte_valid(pte) || !stage2_pte_cacheable(pgt, pte))
+	if (!stage2_pte_cacheable(pgt, pte))
 		return 0;
 
 	if (mm_ops->dcache_clean_inval_poc)
-- 
2.36.1.124.g0e6072fb45-goog