Re: [PATCH 2/2] vdpa: vp_vdpa: don't use hard-coded maximum virtqueue size

From: Jason Wang
Date: Mon Jul 05 2021 - 03:30:02 EST

在 2021/7/5 下午3:26, Michael S. Tsirkin 写道:
On Mon, Jul 05, 2021 at 03:19:10PM +0800, Jason Wang wrote:
This patch switch to read virtqueue size from the capability instead
of depending on the hardcoded value. This allows the per virtqueue
size could be advertised.

Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
So let's add an ioctl for this? It's really a bug we don't..

As explained in patch 1. Qemu doesn't use VHOST_VDPA_GET_VRING_NUM actually. Instead it checks the result VHOST_VDPA_SET_VRING_NUM.

So I change VHOST_VDPA_GET_VRING_NUM to return the minimal size of all the virtqueues.

If you wish we can add a VHOST_VDPA_GET_VRING_NUM2, but I'm not sure it will have a user or not.


drivers/vdpa/virtio_pci/vp_vdpa.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
index 2926641fb586..198f7076e4d9 100644
--- a/drivers/vdpa/virtio_pci/vp_vdpa.c
+++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
@@ -18,7 +18,6 @@
#include <linux/virtio_pci.h>
#include <linux/virtio_pci_modern.h>
-#define VP_VDPA_QUEUE_MAX 256
#define VP_VDPA_DRIVER_NAME "vp_vdpa"
#define VP_VDPA_NAME_SIZE 256
@@ -197,7 +196,10 @@ static void vp_vdpa_set_status(struct vdpa_device *vdpa, u8 status)
static u16 vp_vdpa_get_vq_num_max(struct vdpa_device *vdpa, u16 qid)
+ struct vp_vdpa *vp_vdpa = vdpa_to_vp(vdpa);
+ struct virtio_pci_modern_device *mdev = &vp_vdpa->mdev;
+ return vp_modern_get_queue_size(mdev, qid);
static int vp_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 qid,