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Diffstat (limited to 'arch/x86/kvm/mmu/tdp_mmu.c')
-rw-r--r--arch/x86/kvm/mmu/tdp_mmu.c5
1 files changed, 4 insertions, 1 deletions
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index 08340219c35a..512163d52194 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -592,7 +592,10 @@ static inline int tdp_mmu_set_spte_atomic(struct kvm *kvm,
/*
* Note, fast_pf_fix_direct_spte() can also modify TDP MMU SPTEs and
- * does not hold the mmu_lock.
+ * does not hold the mmu_lock. On failure, i.e. if a different logical
+ * CPU modified the SPTE, try_cmpxchg64() updates iter->old_spte with
+ * the current value, so the caller operates on fresh data, e.g. if it
+ * retries tdp_mmu_set_spte_atomic()
*/
if (!try_cmpxchg64(sptep, &iter->old_spte, new_spte))
return -EBUSY;