[RFC PATCH 01/17] KVM: arm64: Directly read owner id field in stage2_pte_is_counted()

[Oliver Upton]

A subsequent change to KVM will make use of additional bits in invalid
ptes. Prepare for said change by explicitly checking the valid bit and
owner fields in stage2_pte_is_counted()

Signed-off-by: Oliver Upton <oupton at google.com>
---
 arch/arm64/kvm/hyp/pgtable.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 2cb3867eb7c2..e1506da3e2fb 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -172,6 +172,11 @@ static kvm_pte_t kvm_init_invalid_leaf_owner(u8 owner_id)
 	return FIELD_PREP(KVM_INVALID_PTE_OWNER_MASK, owner_id);
 }
 
+static u8 kvm_invalid_pte_owner(kvm_pte_t pte)
+{
+	return FIELD_GET(KVM_INVALID_PTE_OWNER_MASK, pte);
+}
+
 static int kvm_pgtable_visitor_cb(struct kvm_pgtable_walk_data *data, u64 addr,
 				  u32 level, kvm_pte_t *ptep,
 				  enum kvm_pgtable_walk_flags flag)
@@ -679,7 +684,7 @@ static bool stage2_pte_is_counted(kvm_pte_t pte)
 	 * encode ownership of a page to another entity than the page-table
 	 * owner, whose id is 0.
 	 */
-	return !!pte;
+	return kvm_pte_valid(pte) || kvm_invalid_pte_owner(pte);
 }
 
 static void stage2_put_pte(kvm_pte_t *ptep, struct kvm_s2_mmu *mmu, u64 addr,
-- 
2.36.0.rc0.470.gd361397f0d-goog