From 7d29a2407df612b0903cee94fc3469d7335b442c Mon Sep 17 00:00:00 2001
From: Oliver Upton <oliver.upton@linux.dev>
Date: Fri, 2 Dec 2022 18:51:54 +0000
Subject: [PATCH] KVM: arm64: Don't serialize if the access flag isn't set
Of course, if the PTE wasn't changed then there are absolutely no
serialization requirements. Skip the DSB for an unsuccessful update to
the access flag.
Link: https://lore.kernel.org/r/20221202185156.696189-5-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
---
arch/arm64/kvm/hyp/pgtable.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index 204e59e05674d..aa36d896bd8c6 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -1116,10 +1116,14 @@ int kvm_pgtable_stage2_wrprotect(struct kvm_pgtable *pgt, u64 addr, u64 size)
kvm_pte_t kvm_pgtable_stage2_mkyoung(struct kvm_pgtable *pgt, u64 addr)
{
kvm_pte_t pte = 0;
- stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0,
- &pte, NULL,
- KVM_PGTABLE_WALK_HANDLE_FAULT);
- dsb(ishst);
+ int ret;
+
+ ret = stage2_update_leaf_attrs(pgt, addr, 1, KVM_PTE_LEAF_ATTR_LO_S2_AF, 0,
+ &pte, NULL,
+ KVM_PGTABLE_WALK_HANDLE_FAULT);
+ if (!ret)
+ dsb(ishst);
+
return pte;
}
--
2.30.2