On Wed, Jun 02, 2021 at 10:10:42AM +0800, Jason Wang wrote:
> We used to fail the set_vq_state() since it was not supported yet by
> the virtio spec. But if the bus tries to set the state which is equal
> to the device initial state after reset, we can let it go.
>
> This is a must for virtio_vdpa() to set vq state during probe which is
> required for some vDPA parents.
>
> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx>
> ---
> drivers/vdpa/virtio_pci/vp_vdpa.c | 42 ++++++++++++++++++++++++++++---
> 1 file changed, 39 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/vdpa/virtio_pci/vp_vdpa.c b/drivers/vdpa/virtio_pci/vp_vdpa.c
> index c76ebb531212..18bf4a422772 100644
> --- a/drivers/vdpa/virtio_pci/vp_vdpa.c
> +++ b/drivers/vdpa/virtio_pci/vp_vdpa.c
> @@ -210,13 +210,49 @@ static int vp_vdpa_get_vq_state(struct vdpa_device *vdpa, u16 qid,
> return -EOPNOTSUPP;
> }
>
> +static int vp_vdpa_set_vq_state_split(struct vdpa_device *vdpa,
> + const struct vdpa_vq_state *state)
> +{
> + const struct vdpa_vq_state_split *split = &state->split;
> +
> + if (split->avail_index == 0)
> + return 0;
> +
> + return -EOPNOTSUPP;
> +}
> +
> +static int vp_vdpa_set_vq_state_packed(struct vdpa_device *vdpa,
> + const struct vdpa_vq_state *state)
> +{
> + const struct vdpa_vq_state_packed *packed = &state->packed;
> +
> + if (packed->last_avail_counter == 1 &&
Can you elaborate on the requirement on last_avail_counter and
last_used_counter?
> + packed->last_avail_idx == 0 &&
> + packed->last_used_counter == 1 &&
> + packed->last_used_idx == 0)
> + return 0;
> +
> + return -EOPNOTSUPP;
> +}
> +
> static int vp_vdpa_set_vq_state(struct vdpa_device *vdpa, u16 qid,
> const struct vdpa_vq_state *state)
> {
> - /* Note that this is not supported by virtio specification, so
> - * we return -ENOPOTSUPP here. This means we can't support live
> - * migration, vhost device start/stop.
> + struct virtio_pci_modern_device *mdev = vdpa_to_mdev(vdpa);
> +
> + /* Note that this is not supported by virtio specification.
> + * But if the state is by chance equal to the device initial
> + * state, we can let it go.
> */
> + if ((vp_modern_get_status(mdev) & VIRTIO_CONFIG_S_FEATURES_OK) &&
> + !vp_modern_get_queue_enable(mdev, qid)) {
> + if (vp_modern_get_driver_features(mdev) &
> + BIT_ULL(VIRTIO_F_RING_PACKED))
> + return vp_vdpa_set_vq_state_packed(vdpa, state);
> + else
> + return vp_vdpa_set_vq_state_split(vdpa, state);
> + }
> +
> return -EOPNOTSUPP;
> }
>
> --
> 2.25.1
>
