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Subject[PATCH v2 4/6] KVM: MMU: don't atomicly set spte if it's not present
If the old mapping is not present, the spte.a is not lost, so no need
atomic operation to set it

Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
---
arch/x86/kvm/mmu.c | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c
index b3896bf..4123e8e 100644
--- a/arch/x86/kvm/mmu.c
+++ b/arch/x86/kvm/mmu.c
@@ -307,9 +307,10 @@ static void update_spte(u64 *sptep, u64 new_spte)
{
u64 old_spte;

- if (!shadow_accessed_mask || (new_spte & shadow_accessed_mask)) {
+ if (!shadow_accessed_mask || (new_spte & shadow_accessed_mask) ||
+ !is_rmap_spte(*sptep))
__set_spte(sptep, new_spte);
- } else {
+ else {
old_spte = __xchg_spte(sptep, new_spte);
if (old_spte & shadow_accessed_mask)
mark_page_accessed(pfn_to_page(spte_to_pfn(old_spte)));
--
1.6.1.2



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