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[v2,11/15] KVM: arm64: Split init and set for table PTE

Message ID 20221007233019.459842-1-oliver.upton@linux.dev (mailing list archive)
State New, archived
Headers show
Series KVM: arm64: Parallel stage-2 fault handling | expand

Commit Message

Oliver Upton Oct. 7, 2022, 11:30 p.m. UTC 
Create a helper to initialize a table and directly call
smp_store_release() to install it (for now). Prepare for a subsequent
change that generalizes PTE writes with a helper.

Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
 arch/arm64/kvm/hyp/pgtable.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)
diff mbox series

Patch

diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 8aebddcdd593..f649a2251a35 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -136,16 +136,13 @@  static void kvm_clear_pte(kvm_pte_t *ptep)
 	WRITE_ONCE(*ptep, 0);
 }
 
-static void kvm_set_table_pte(kvm_pte_t *ptep, kvm_pte_t *childp,
-			      struct kvm_pgtable_mm_ops *mm_ops)
+static kvm_pte_t kvm_init_table_pte(kvm_pte_t *childp, struct kvm_pgtable_mm_ops *mm_ops)
 {
-	kvm_pte_t old = *ptep, pte = kvm_phys_to_pte(mm_ops->virt_to_phys(childp));
+	kvm_pte_t pte = kvm_phys_to_pte(mm_ops->virt_to_phys(childp));
 
 	pte |= FIELD_PREP(KVM_PTE_TYPE, KVM_PTE_TYPE_TABLE);
 	pte |= KVM_PTE_VALID;
-
-	WARN_ON(kvm_pte_valid(old));
-	smp_store_release(ptep, pte);
+	return pte;
 }
 
 static kvm_pte_t kvm_init_valid_leaf_pte(u64 pa, kvm_pte_t attr, u32 level)
@@ -410,7 +407,7 @@  static bool hyp_map_walker_try_leaf(const struct kvm_pgtable_visit_ctx *ctx,
 static int hyp_map_walker(const struct kvm_pgtable_visit_ctx *ctx,
 			  enum kvm_pgtable_walk_flags visit)
 {
-	kvm_pte_t *childp;
+	kvm_pte_t *childp, new;
 	struct hyp_map_data *data = ctx->arg;
 	struct kvm_pgtable_mm_ops *mm_ops = ctx->mm_ops;
 
@@ -424,8 +421,10 @@  static int hyp_map_walker(const struct kvm_pgtable_visit_ctx *ctx,
 	if (!childp)
 		return -ENOMEM;
 
-	kvm_set_table_pte(ctx->ptep, childp, mm_ops);
+	new = kvm_init_table_pte(childp, mm_ops);
 	mm_ops->get_page(ctx->ptep);
+	smp_store_release(ctx->ptep, new);
+
 	return 0;
 }
 
@@ -821,8 +820,9 @@  static int stage2_map_walk_leaf(const struct kvm_pgtable_visit_ctx *ctx,
 	if (stage2_pte_is_counted(ctx->old))
 		stage2_put_pte(ctx, data->mmu, mm_ops);
 
-	kvm_set_table_pte(ctx->ptep, childp, mm_ops);
+	new = kvm_init_table_pte(childp, mm_ops);
 	mm_ops->get_page(ctx->ptep);
+	smp_store_release(ctx->ptep, new);
 
 	return 0;
 }