Commit 565f3be2 authored by Takuya Yoshikawa's avatar Takuya Yoshikawa Committed by Avi Kivity
Browse files

KVM: mmu_notifier: Flush TLBs before releasing mmu_lock 



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: default avatarTakuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent db3fe4eb

virt/kvm/kvm_main.c

+10 −9
Original line number Diff line number Diff line
@@ -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;

}