Re: [dpdk-stable] [17.11] net/virtio-user: do not reset owner when driver resets

[Yongseok Koh <yskoh@mellanox.com>]

> On Dec 6, 2018, at 10:58 PM, Yahui Cao <yahui.cao@intel.com> wrote:
> 
> [ backported from upstream commit 74dc6746a0f195907ec487df7de18a856108482f ]
> 
> When driver resets the device, virtio-user just needs to send
> GET_VRING_BASE messages to stop the vhost backend, and that's
> what QEMU does. With this change, we won't need to set owner
> when starting virtio-user device anymore. This will help us to
> get rid of below error message on startup:
> 
> vhost_kernel_ioctl(): VHOST_SET_OWNER failed: Device or resource busy
> 
> Fixes: bce7e9050f9b ("net/virtio-user: fix start with kernel vhost")
> Fixes: 0d6a8752ac9d ("net/virtio-user: fix crash as features change")
> 
> Signed-off-by: Tiwei Bie <tiwei.bie@intel.com>
> Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> Signed-off-by: Yahui Cao <yahui.cao@intel.com>
> ---

Applied to stable/17.11

Thanks,
Yongseok

> .../net/virtio/virtio_user/virtio_user_dev.c   | 18 ++++++++++++++----
> 1 file changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> index 7ce512c76..b13e77f5f 100644
> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> @@ -166,17 +166,27 @@ virtio_user_start_device(struct virtio_user_dev *dev)
> 
> int virtio_user_stop_device(struct virtio_user_dev *dev)
> {
> +	struct vhost_vring_state state;
> 	uint32_t i;
> +	int error = 0;
> 
> 	for (i = 0; i < dev->max_queue_pairs; ++i)
> 		dev->ops->enable_qp(dev, i, 0);
> 
> -	if (dev->ops->send_request(dev, VHOST_USER_RESET_OWNER, NULL) < 0) {
> -		PMD_DRV_LOG(INFO, "Failed to reset the device\n");
> -		return -1;
> +	/* Stop the backend. */
> +	for (i = 0; i < dev->max_queue_pairs * 2; ++i) {
> +		state.index = i;
> +		if (dev->ops->send_request(dev, VHOST_USER_GET_VRING_BASE,
> +					   &state) < 0) {
> +			PMD_DRV_LOG(ERR, "get_vring_base failed, index=%u\n",
> +				    i);
> +			error = -1;
> +			goto out;
> +		}
> 	}
> 
> -	return 0;
> +out:
> +	return error;
> }
> 
> static inline void
> -- 
> 2.17.1
>