diff options
| author |   Lan Tianyu <tianyu.lan@intel.com> | 2016-03-13 11:10:24 +0800 |
|---|---|---|
| committer |   Paolo Bonzini <pbonzini@redhat.com> | 2016-03-22 16:38:27 +0100 |
| commit | 9753f529156d03112d1ff6f3758ccd6fa6faf189 (patch) | |
| tree | 675585108c6efb772d2d0503468fcef602237044 /arch | |
| parent | KVM, pkeys: expose CPUID/CR4 to guest (diff) | |
| download | linux-dev-9753f529156d03112d1ff6f3758ccd6fa6faf189.tar.xz linux-dev-9753f529156d03112d1ff6f3758ccd6fa6faf189.zip | |
KVM: Remove redundant smp_mb() in the kvm_mmu_commit_zap_page()
There is already a barrier inside of kvm_flush_remote_tlbs() which can
help to make sure everyone sees our modifications to the page tables and
see changes to vcpu->mode here. So remove the smp_mb in the
kvm_mmu_commit_zap_page() and update the comment.
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/kvm/mmu.c | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index e46a81f4856e..fc8ab1f67d00 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2390,14 +2390,13 @@ static void kvm_mmu_commit_zap_page(struct kvm *kvm, return; /* - * wmb: make sure everyone sees our modifications to the page tables - * rmb: make sure we see changes to vcpu->mode - */ - smp_mb(); - - /* - * Wait for all vcpus to exit guest mode and/or lockless shadow - * page table walks. + * We need to make sure everyone sees our modifications to + * the page tables and see changes to vcpu->mode here. The barrier + * in the kvm_flush_remote_tlbs() achieves this. This pairs + * with vcpu_enter_guest and walk_shadow_page_lockless_begin/end. + * + * In addition, kvm_flush_remote_tlbs waits for all vcpus to exit + * guest mode and/or lockless shadow page table walks. */ kvm_flush_remote_tlbs(kvm); |