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-rw-r--r--virt/kvm/kvm_main.c26
1 files changed, 20 insertions, 6 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index f5283438ee05..1cc6e2e19982 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -671,6 +671,7 @@ static void update_memslots(struct kvm_memslots *slots,
WARN_ON(mslots[i].id != id);
if (!new->npages) {
+ WARN_ON(!mslots[i].npages);
new->base_gfn = 0;
if (mslots[i].npages)
slots->used_slots--;
@@ -687,12 +688,25 @@ static void update_memslots(struct kvm_memslots *slots,
slots->id_to_index[mslots[i].id] = i;
i++;
}
- while (i > 0 &&
- new->base_gfn > mslots[i - 1].base_gfn) {
- mslots[i] = mslots[i - 1];
- slots->id_to_index[mslots[i].id] = i;
- i--;
- }
+
+ /*
+ * The ">=" is needed when creating a slot with base_gfn == 0,
+ * so that it moves before all those with base_gfn == npages == 0.
+ *
+ * On the other hand, if new->npages is zero, the above loop has
+ * already left i pointing to the beginning of the empty part of
+ * mslots, and the ">=" would move the hole backwards in this
+ * case---which is wrong. So skip the loop when deleting a slot.
+ */
+ if (new->npages) {
+ while (i > 0 &&
+ new->base_gfn >= mslots[i - 1].base_gfn) {
+ mslots[i] = mslots[i - 1];
+ slots->id_to_index[mslots[i].id] = i;
+ i--;
+ }
+ } else
+ WARN_ON_ONCE(i != slots->used_slots);
mslots[i] = *new;
slots->id_to_index[mslots[i].id] = i;