diff options
| author | Uros Bizjak <ubizjak@gmail.com> | 2022-05-20 17:46:35 +0300 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2022-06-15 15:12:17 +0300 |
| commit | 2db2f46fdfc25691f3e90224e78bc5b2fc23dcd7 (patch) | |
| tree | 1940c829fbe942726c44d801206b3ed482cf70b1 | |
| parent | 0ac304de73b37b66793d6cc1ad3a03886aa79791 (diff) | |
| download | linux-2db2f46fdfc25691f3e90224e78bc5b2fc23dcd7.tar.xz | |
KVM: x86/mmu: Use try_cmpxchg64 in fast_pf_fix_direct_spte
Use try_cmpxchg64 instead of cmpxchg64 (*ptr, old, new) != old in
fast_pf_fix_direct_spte. cmpxchg returns success in ZF flag, so this
change saves a compare after cmpxchg (and related move instruction
in front of cmpxchg).
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Cc: Wanpeng Li <wanpengli@tencent.com>
Cc: Jim Mattson <jmattson@google.com>
Cc: Joerg Roedel <joro@8bytes.org>
Message-Id: <20220520144635.63134-1-ubizjak@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
| -rw-r--r-- | arch/x86/kvm/mmu/mmu.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 0a4438544c0d..34785bc3077d 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -3093,7 +3093,7 @@ fast_pf_fix_direct_spte(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault, * * Compare with set_spte where instead shadow_dirty_mask is set. */ - if (cmpxchg64(sptep, old_spte, new_spte) != old_spte) + if (!try_cmpxchg64(sptep, &old_spte, new_spte)) return false; if (is_writable_pte(new_spte) && !is_writable_pte(old_spte)) |