According to the Virtio Specification, the Queue Size parameter of a
virtqueue corresponds to the maximum number of descriptors in that
queue, and it does not have to be a power of 2 for packed virtqueues.
However, the virtio_pci_modern driver enforced a power of 2 check for
virtqueue sizes, which is unnecessary and restrictive for packed
virtuqueue.
Split virtqueue still needs to check the virtqueue size is power_of_2
which has been done in vring_alloc_queue_split of the virtio_ring layer.
To validate this change, we tested various virtqueue sizes for packed
rings, including 128, 256, 512, 100, 200, 500, and 1000, with
CONFIG_PAGE_POISONING enabled, and all tests passed successfully.
Signed-off-by: Feng Liu <feliu@xxxxxxxxxx>
Reviewed-by: Jiri Pirko <jiri@xxxxxxxxxx>
---
v0 -> v1
feedbacks from Jason Wang and Michael S. Tsirkin
- remove power_of_2 check of virtqueue size
v1 -> v2
feedbacks from Parav Pandit and Jiri Pirko
- keep power_of_2 check of split virtqueue in vring_alloc_queue_split of
virtio_ring layer.
---
drivers/virtio/virtio_pci_modern.c | 5 -----
1 file changed, 5 deletions(-)
diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
index 9e496e288cfa..6e713904d8e8 100644
--- a/drivers/virtio/virtio_pci_modern.c
+++ b/drivers/virtio/virtio_pci_modern.c
@@ -310,11 +310,6 @@ static struct virtqueue *setup_vq(struct virtio_pci_device *vp_dev,
if (!num || vp_modern_get_queue_enable(mdev, index))
return ERR_PTR(-ENOENT);
- if (!is_power_of_2(num)) {
- dev_warn(&vp_dev->pci_dev->dev, "bad queue size %u", num);
- return ERR_PTR(-EINVAL);
- }
-
info->msix_vector = msix_vec;
/* create the vring */
--
2.34.1
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