On Mon, Jul 05, 2021 at 03:19:09PM +0800, Jason Wang wrote:

Virtio spec allows the device to specify the per virtqueue max queue
size. vDPA needs to adapt to this flexibility. E.g Qemu advertise a
small control virtqueue for virtio-net.

So this patch adds a index parameter to get_vq_num_max bus operations
for the device to report its per virtqueue max queue size.

Both VHOST_VDPA_GET_VRING_NUM and VDPA_ATTR_DEV_MAX_VQ_SIZE assume a
global maximum size. So we iterate all the virtqueues to return the
minimal size in this case. Actually, the VHOST_VDPA_GET_VRING_NUM is
not a must for the userspace. Userspace may choose to check the
VHOST_SET_VRING_NUM for proving or validating the maximum virtqueue
size. Anyway, we can invent a per vq version of
VHOST_VDPA_GET_VRING_NUM in the future if it's necessary.

Signed-off-by: Jason Wang <redacted>
---
 drivers/vdpa/ifcvf/ifcvf_main.c   |  2 +-
 drivers/vdpa/mlx5/net/mlx5_vnet.c |  2 +-
 drivers/vdpa/vdpa.c               | 22 +++++++++++++++++++++-
 drivers/vdpa/vdpa_sim/vdpa_sim.c  |  2 +-
 drivers/vdpa/virtio_pci/vp_vdpa.c |  2 +-
 drivers/vhost/vdpa.c              |  9 ++++++---
 drivers/virtio/virtio_vdpa.c      |  2 +-
 include/linux/vdpa.h              |  5 ++++-
 8 files changed, 36 insertions(+), 10 deletions(-)

Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>