Maxime Coquelin <maxime.coque...@redhat.com> writes:
> This patch adds VHOST_USER_PROTOCOL_F_MTU protocol feature.
>
> If supported, QEMU sends VHOST_USER_GET_MTU request to the client,
> and expects a u64 reply containing the MTU advised for the guest.
>
> Cc: Michael S. Tsirkin <m...@redhat.com>
> Cc: Aaron Conole <acon...@redhat.com>
> Signed-off-by: Maxime Coquelin <maxime.coque...@redhat.com>
> ---
> hw/virtio/vhost-user.c | 11 +++++++++++
> include/hw/virtio/vhost.h | 1 +
> 2 files changed, 12 insertions(+)
>
> diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
> index 7ee92b3..eaf007d 100644
> --- a/hw/virtio/vhost-user.c
> +++ b/hw/virtio/vhost-user.c
> @@ -32,6 +32,7 @@ enum VhostUserProtocolFeature {
> VHOST_USER_PROTOCOL_F_LOG_SHMFD = 1,
> VHOST_USER_PROTOCOL_F_RARP = 2,
> VHOST_USER_PROTOCOL_F_REPLY_ACK = 3,
> + VHOST_USER_PROTOCOL_F_MTU = 4,
>
> VHOST_USER_PROTOCOL_F_MAX
> };
> @@ -59,6 +60,7 @@ typedef enum VhostUserRequest {
> VHOST_USER_GET_QUEUE_NUM = 17,
> VHOST_USER_SET_VRING_ENABLE = 18,
> VHOST_USER_SEND_RARP = 19,
> + VHOST_USER_GET_MTU = 20,
> VHOST_USER_MAX
> } VhostUserRequest;
>
> @@ -186,6 +188,7 @@ static bool vhost_user_one_time_request(VhostUserRequest
> request)
> case VHOST_USER_RESET_OWNER:
> case VHOST_USER_SET_MEM_TABLE:
> case VHOST_USER_GET_QUEUE_NUM:
> + case VHOST_USER_GET_MTU:
> return true;
> default:
> return false;
> @@ -602,6 +605,14 @@ static int vhost_user_init(struct vhost_dev *dev, void
> *opaque)
> return err;
> }
> }
> +
> + /* query the MTU we support if backend supports MTU feature */
> + if (dev->protocol_features & (1ULL << VHOST_USER_PROTOCOL_F_MTU)) {
> + err = vhost_user_get_u64(dev, VHOST_USER_GET_MTU, &dev->mtu);
> + if (err < 0) {
> + return err;
> + }
> + }
> }
>
> if (dev->migration_blocker == NULL &&
> diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
> index 1fe5aad..c674a05 100644
> --- a/include/hw/virtio/vhost.h
> +++ b/include/hw/virtio/vhost.h
> @@ -51,6 +51,7 @@ struct vhost_dev {
> uint64_t backend_features;
> uint64_t protocol_features;
> uint64_t max_queues;
> + uint64_t mtu;
Just a question why the MTU is stored as a u64? would uint16_t make
more sense - then we can be sure we never have an excessively large mtu
value.
What do you think?
> bool started;
> bool log_enabled;
> uint64_t log_size;
