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[virtio] Cap queue size to MAX_QUEUE_NUM 

vpm_find_vqs incorrectly accepted the host provided queue size with no
regard to iPXE's internal limitations. Virtio 1.0 makes it possible for
the driver to override the queue size to reduce memory requirements and
iPXE is a great use case for this feature.

Also removing the extra vq->vring.num assignment which is already
handled in vring_init.

Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>
This commit is contained in:
Ladi Prosek 2016-12-16 10:54:32 +01:00 committed by Michael Brown
parent dfbbc16ae3
commit e45451c699
2 changed files with 10 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

8
src/drivers/bus/virtio-pci.c
View File

@ -358,12 +358,18 @@ int vpm_find_vqs(struct virtio_pci_modern_device *vdev,
return -EINVAL;
}
if (size > MAX_QUEUE_NUM) {
/* iPXE networking tends to be not perf critical so there's no
* need to accept large queue sizes.
*/
size = MAX_QUEUE_NUM;
}
vq = &vqs[i];
vq->queue_index = i;
/* get offset of notification word for this vq */
off = vpm_ioread16(vdev, &vdev->common, COMMON_OFFSET(queue_notify_off));
vq->vring.num = size;
vring_init(&vq->vring, size, (unsigned char *)vq->queue);

6
src/include/ipxe/virtio-ring.h
View File

@ -95,7 +95,7 @@ static inline void vring_init(struct vring *vr,
unsigned int i;
unsigned long pa;
vr->num = num;
vr->num = num;
/* physical address of desc must be page aligned */
@ -103,13 +103,13 @@ static inline void vring_init(struct vring *vr,
pa = (pa + PAGE_MASK) & ~PAGE_MASK;
vr->desc = phys_to_virt(pa);
vr->avail = (struct vring_avail *)&vr->desc[num];
vr->avail = (struct vring_avail *)&vr->desc[num];
/* physical address of used must be page aligned */
pa = virt_to_phys(&vr->avail->ring[num]);
pa = (pa + PAGE_MASK) & ~PAGE_MASK;
vr->used = phys_to_virt(pa);
vr->used = phys_to_virt(pa);
for (i = 0; i < num - 1; i++)
vr->desc[i].next = i + 1;