Commit 3850d29f authored by Brian Foley's avatar Brian Foley Committed by Rusty Russell

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: default avatarBrian Foley <brian.foley@arm.com>
Signed-off-by: default avatarPawel Moll <pawel.moll@arm.com>
Signed-off-by: default avatarRusty Russell <rusty@rustcorp.com.au>
parent 74a74b37
...@@ -334,8 +334,8 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index, ...@@ -334,8 +334,8 @@ static struct virtqueue *vm_setup_vq(struct virtio_device *vdev, unsigned index,
while (1) { while (1) {
size = PAGE_ALIGN(vring_size(info->num, size = PAGE_ALIGN(vring_size(info->num,
VIRTIO_MMIO_VRING_ALIGN)); VIRTIO_MMIO_VRING_ALIGN));
/* Already smallest possible allocation? */ /* Did the last iter shrink the queue below minimum size? */
if (size <= VIRTIO_MMIO_VRING_ALIGN * 2) { if (size < VIRTIO_MMIO_VRING_ALIGN * 2) {
err = -ENOMEM; err = -ENOMEM;
goto error_alloc_pages; goto error_alloc_pages;
} }
......
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