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authorBrian Foley <brian.foley@arm.com>2012-09-24 14:33:41 +0100
committerRusty Russell <rusty@rustcorp.com.au>2012-09-28 15:05:16 +0930
commit3850d29fc40f3494a3e9c3aac45b6afe53526449 (patch)
treeb80c5c7819de0bfc2a75a55939568f3784ed5dbf /drivers/virtio/virtio_mmio.c
parent74a74b376c997645b32a4fdf8e76705a00ae097a (diff)
downloadlinux-3850d29fc40f3494a3e9c3aac45b6afe53526449.tar.bz2
virtio_mmio: fix off by one error allocating queue
vm_setup_vq fails to allow VirtQueues needing only 2 pages of storage, as it should. Found with a kernel using 64kB pages, but can be provoked if a virtio device reports QueueNumMax where the descriptor table and available ring fit in one page, and the used ring on the second (<= 227 descriptors with 4kB pages and <= 3640 with 64kB pages.) Signed-off-by: Brian Foley <brian.foley@arm.com> Signed-off-by: Pawel Moll <pawel.moll@arm.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'drivers/virtio/virtio_mmio.c')
-rw-r--r--drivers/virtio/virtio_mmio.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index 5d7fee385b70..09edeecd42a5 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -334,8 +334,8 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
while (1) {
size = PAGE_ALIGN(vring_size(info->num,
VIRTIO_MMIO_VRING_ALIGN));
- /* Already smallest possible allocation? */
- if (size <= VIRTIO_MMIO_VRING_ALIGN * 2) {
+ /* Did the last iter shrink the queue below minimum size? */
+ if (size < VIRTIO_MMIO_VRING_ALIGN * 2) {
err = -ENOMEM;
goto error_alloc_pages;
}