From: Marcelo Tosatti Date: Fri, 18 May 2012 17:58:45 -0300 Subject: KVM: mmu_notifier: Flush TLBs before releasing mmu_lock From: Takuya Yoshikawa (cherry picked from commit 565f3be2174611f364405bbea2d86e153c2e7e78 Other threads may process the same page in that small window and skip TLB flush and then return before these functions do flush. Signed-off-by: Takuya Yoshikawa Signed-off-by: Marcelo Tosatti Signed-off-by: Avi Kivity Signed-off-by: Ben Hutchings --- virt/kvm/kvm_main.c | 19 ++++++++++--------- 1 files changed, 10 insertions(+), 9 deletions(-) diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index e401c1b..9ffac2e 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c @@ -289,15 +289,15 @@ static void kvm_mmu_notifier_invalidate_page(struct mmu_notifier *mn, */ idx = srcu_read_lock(&kvm->srcu); spin_lock(&kvm->mmu_lock); + kvm->mmu_notifier_seq++; need_tlb_flush = kvm_unmap_hva(kvm, address) | kvm->tlbs_dirty; - spin_unlock(&kvm->mmu_lock); - srcu_read_unlock(&kvm->srcu, idx); - /* we've to flush the tlb before the pages can be freed */ if (need_tlb_flush) kvm_flush_remote_tlbs(kvm); + spin_unlock(&kvm->mmu_lock); + srcu_read_unlock(&kvm->srcu, idx); } static void kvm_mmu_notifier_change_pte(struct mmu_notifier *mn, @@ -335,12 +335,12 @@ static void kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn, for (; start < end; start += PAGE_SIZE) need_tlb_flush |= kvm_unmap_hva(kvm, start); need_tlb_flush |= kvm->tlbs_dirty; - spin_unlock(&kvm->mmu_lock); - srcu_read_unlock(&kvm->srcu, idx); - /* we've to flush the tlb before the pages can be freed */ if (need_tlb_flush) kvm_flush_remote_tlbs(kvm); + + spin_unlock(&kvm->mmu_lock); + srcu_read_unlock(&kvm->srcu, idx); } static void kvm_mmu_notifier_invalidate_range_end(struct mmu_notifier *mn, @@ -378,13 +378,14 @@ static int kvm_mmu_notifier_clear_flush_young(struct mmu_notifier *mn, idx = srcu_read_lock(&kvm->srcu); spin_lock(&kvm->mmu_lock); - young = kvm_age_hva(kvm, address); - spin_unlock(&kvm->mmu_lock); - srcu_read_unlock(&kvm->srcu, idx); + young = kvm_age_hva(kvm, address); if (young) kvm_flush_remote_tlbs(kvm); + spin_unlock(&kvm->mmu_lock); + srcu_read_unlock(&kvm->srcu, idx); + return young; } -- 1.7.6.4 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html