path: root/virt
diff options
authorLai Jiangshan <>2020-12-17 23:41:18 +0800
committerPaolo Bonzini <>2021-01-07 18:11:30 -0500
commit88bf56d04bc3564542049ec4ec168a8b60d0b48c (patch)
tree9de20433d909e333c8c118d2ee85ecfde6a01ae8 /virt
parentde7860c8a388e4cb757c7da26889b9e2641ffcfe (diff)
kvm: check tlbs_dirty directly
In kvm_mmu_notifier_invalidate_range_start(), tlbs_dirty is used as: need_tlb_flush |= kvm->tlbs_dirty; with need_tlb_flush's type being int and tlbs_dirty's type being long. It means that tlbs_dirty is always used as int and the higher 32 bits is useless. We need to check tlbs_dirty in a correct way and this change checks it directly without propagating it to need_tlb_flush. Note: it's _extremely_ unlikely this neglecting of higher 32 bits can cause problems in practice. It would require encountering tlbs_dirty on a 4 billion count boundary, and KVM would need to be using shadow paging or be running a nested guest. Cc: Fixes: a4ee1ca4a36e ("KVM: MMU: delay flush all tlbs on sync_page path") Signed-off-by: Lai Jiangshan <> Message-Id: <> Signed-off-by: Paolo Bonzini <>
Diffstat (limited to 'virt')
1 files changed, 1 insertions, 2 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 3abcb2ce5b7d..19dae28904f7 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -485,9 +485,8 @@ static int kvm_mmu_notifier_invalidate_range_start(struct mmu_notifier *mn,
need_tlb_flush = kvm_unmap_hva_range(kvm, range->start, range->end,
- need_tlb_flush |= kvm->tlbs_dirty;
/* we've to flush the tlb before the pages can be freed */
- if (need_tlb_flush)
+ if (need_tlb_flush || kvm->tlbs_dirty)