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virtio-balloon: Fix wrong sign extension of PFNs 

If we directly cast from int to uint64_t, we will first sign-extend to
an int64_t, which is wrong. We actually want to treat the PFNs like
unsigned values.

As far as I can see, this dates back to the initial virtio-balloon
commit, but wasn't triggered as fairly big guests would be required.

Cc: qemu-stable@nongnu.org
Reported-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190722134108.22151-2-david@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
master
David Hildenbrand 2019-07-22 15:41:03 +02:00 committed by Michael S. Tsirkin
parent ee4b0c8686
commit ffa207d082
1 changed files with 1 additions and 1 deletions
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2
hw/virtio/virtio-balloon.c
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@ -343,8 +343,8 @@ static void virtio_balloon_handle_output(VirtIODevice *vdev, VirtQueue *vq)
}
while (iov_to_buf(elem->out_sg, elem->out_num, offset, &pfn, 4) == 4) {
unsigned int p = virtio_ldl_p(vdev, &pfn);
hwaddr pa;
int p = virtio_ldl_p(vdev, &pfn);
pa = (hwaddr) p << VIRTIO_BALLOON_PFN_SHIFT;
offset += 4;