From dbaff30940d6ef9bfa5f1f0c819cf3344ed3129f Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Sat, 27 Dec 2014 21:08:16 +0100
Subject: [PATCH] kvm: warn on more invariant breakage
Modifying a non-existent slot is not allowed. Also check that the
first loop doesn't move a deleted slot beyond the used part of
the mslots array.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
virt/kvm/kvm_main.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 050974c051b5..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--;
@@ -704,7 +705,8 @@ static void update_memslots(struct kvm_memslots *slots,
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;
--
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