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: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 8340e0e..e4431ad 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -289,15 +289,15 @@
*/
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 @@
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 @@
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;
}