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@xxxxxxxxx> --- arch/x86/kvm/mmu.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 2463de0..5e795af 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2390,14 +2390,12 @@ 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() helps us to achieve these. This pairs + * with vcpu_enter_guest and walk_shadow_page_lockless_begin/end. + * In addition, wait for all vcpus to exit guest mode and/or lockless + * shadow page table walks. */ kvm_flush_remote_tlbs(kvm); -- 1.8.4.rc0.1.g8f6a3e5.dirty -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
