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| author | Brian Foley <brian.foley@arm.com> | 2012-10-04 19:31:28 -0500 |
|---|---|---|
| committer | Omar Ramirez Luna <omar.luna@linaro.org> | 2012-10-04 20:18:04 -0500 |
| commit | d036c46bacf4594b51ba0b6dda90f28c0ce3f8ee (patch) | |
| tree | 2708b8c945d20df7911cacebcd3bad7ffe78c356 | |
| parent | 721f0dfdd7c343bbc6d7b4d65c6dc82a1e592ae2 (diff) | |
| download | linux-aarch64-d036c46bacf4594b51ba0b6dda90f28c0ce3f8ee.tar.gz | |
virtio_mmio: Don't attempt to create empty virtqueues
If a virtio device reports a QueueNumMax of 0, vring_new_virtqueue()
doesn't check this, and thanks to an unsigned (i < num - 1) loop
guard, scribbles over memory when initialising the free list.
Avoid by not trying to create zero-descriptor queues, as there's no
way to do any I/O with one.
Signed-off-by: Brian Foley <brian.foley@arm.com>
Signed-off-by: Pawel Moll <pawel.moll@arm.com>
Signed-off-by: Omar Ramirez Luna <omar.luna@linaro.org>
| -rw-r--r-- | drivers/virtio/virtio_mmio.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c index 58e2d78a449..6979c1b9e7c 100644 --- a/drivers/virtio/virtio_mmio.c +++ b/drivers/virtio/virtio_mmio.c @@ -332,6 +332,16 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index, * and two rings (which makes it "alignment_size * 2") */ info->num = readl(vm_dev->base + VIRTIO_MMIO_QUEUE_NUM_MAX); + + /* If the device reports a 0 entry queue, we won't be able to + * use it to perform I/O, and vring_new_virtqueue() can't create + * empty queues anyway, so don't bother to set up the device. + */ + if (info->num == 0) { + err = -ENOENT; + goto error_alloc_pages; + } + while (1) { size = PAGE_ALIGN(vring_size(info->num, VIRTIO_MMIO_VRING_ALIGN)); |