Re: [RFC PATCH v8 14/19] virtio/vsock: enable SEQPACKET for transport

Stefano Garzarella
2021-04-21T09:22:18Z

On Tue, Apr 13, 2021 at 03:45:49PM +0300, Arseny Krasnov wrote:
>This adds
>1) SEQPACKET ops for virtio transport and 'seqpacket_allow()' callback.
>2) Handling of SEQPACKET bit: guest tries to negotiate it with vhost.
>
>Signed-off-by: Arseny Krasnov <arseny.krasnov@kaspersky.com>
>---
>v7 -> v8:
> - This patch merged with patch which adds SEQPACKET feature bit to
> virtio transport.
>
> net/vmw_vsock/virtio_transport.c | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
>diff --git a/net/vmw_vsock/virtio_transport.c b/net/vmw_vsock/virtio_transport.c
>index 2700a63ab095..ee99bd919a12 100644
>--- a/net/vmw_vsock/virtio_transport.c
>+++ b/net/vmw_vsock/virtio_transport.c
>@@ -443,6 +443,8 @@ static void virtio_vsock_rx_done(struct virtqueue
>*vq)
> queue_work(virtio_vsock_workqueue, &vsock->rx_work);
> }
>
>+static bool virtio_transport_seqpacket_allow(void);
>+
> static struct virtio_transport virtio_transport = {
> .transport = {
> .module = THIS_MODULE,
>@@ -469,6 +471,10 @@ static struct virtio_transport virtio_transport = {
> .stream_is_active = virtio_transport_stream_is_active,
> .stream_allow = virtio_transport_stream_allow,
>
>+ .seqpacket_dequeue = virtio_transport_seqpacket_dequeue,
>+ .seqpacket_enqueue = virtio_transport_seqpacket_enqueue,
>+ .seqpacket_allow = virtio_transport_seqpacket_allow,
>+
> .notify_poll_in = virtio_transport_notify_poll_in,
> .notify_poll_out =
> virtio_transport_notify_poll_out,
> .notify_recv_init = virtio_transport_notify_recv_init,
>@@ -483,8 +489,14 @@ static struct virtio_transport virtio_transport = {
> },
>
> .send_pkt = virtio_transport_send_pkt,
>+ .seqpacket_allow = false
> };
>
>+static bool virtio_transport_seqpacket_allow(void)
>+{
>+ return virtio_transport.seqpacket_allow;
>+}
>+
> static void virtio_transport_rx_work(struct work_struct *work)
> {
> struct virtio_vsock *vsock =
>@@ -612,6 +624,10 @@ static int virtio_vsock_probe(struct virtio_device *vdev)
> rcu_assign_pointer(the_virtio_vsock, vsock);
>
> mutex_unlock(&the_virtio_vsock_mutex);
>+
>+ if (vdev->features & (1ULL << VIRTIO_VSOCK_F_SEQPACKET))
>+ virtio_transport.seqpacket_allow = true;
>+

virtio-vsock devices can be hot-plugged and hot-unplugged, so we should
reset virtio_transport.seqpacket_allow at every probe.

Now thinking about it more, would it be better to save this information
in struct virtio_vsock instead of struct virtio_transport?

> return 0;
>
> out:
>@@ -695,6 +711,7 @@ static struct virtio_device_id id_table[] = {
> };
>
> static unsigned int features[] = {
>+ VIRTIO_VSOCK_F_SEQPACKET
> };
>
> static struct virtio_driver virtio_vsock_driver = {
>--
>2.25.1
>