Re: [PATCH net-next v8 06/14] vsock/virtio: add netns to virtio transport common

Stefano Garzarella
2025-11-06T16:20:20Z

On Thu, Oct 23, 2025 at 11:27:45AM -0700, Bobby Eshleman wrote:
>From: Bobby Eshleman <bobbyeshleman@meta.com>
>
>Enable network namespace support in the virtio-vsock common transport
>layer by declaring namespace pointers in the transmit and receive
>paths.
>
>The changes include:
>1. Add a 'net' field to virtio_vsock_pkt_info to carry the namespace
> pointer for outgoing packets.
>2. Store the namespace and namespace mode in the skb control buffer when
> allocating packets (except for VIRTIO_VSOCK_OP_RST packets which do
> not have an associated socket).
>3. Retrieve namespace information from skbs on the receive path for
> lookups using vsock_find_connected_socket_net() and
> vsock_find_bound_socket_net().
>
>This allows users of virtio transport common code
>(vhost-vsock/virtio-vsock) to later enable namespace support.
>
>Signed-off-by: Bobby Eshleman <bobbyeshleman@meta.com>
>---
>Changes in v7:
>- add comment explaining the !vsk case in virtio_transport_alloc_skb()
>---
> include/linux/virtio_vsock.h | 1 +
> net/vmw_vsock/virtio_transport_common.c | 21 +++++++++++++++++++--
> 2 files changed, 20 insertions(+), 2 deletions(-)
>
>diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
>index 29290395054c..f90646f82993 100644
>--- a/include/linux/virtio_vsock.h
>+++ b/include/linux/virtio_vsock.h
>@@ -217,6 +217,7 @@ struct virtio_vsock_pkt_info {
> u32 remote_cid, remote_port;
> struct vsock_sock *vsk;
> struct msghdr *msg;
>+ struct net *net;
> u32 pkt_len;
> u16 type;
> u16 op;
>diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c
>index dcc8a1d5851e..b8e52c71920a 100644
>--- a/net/vmw_vsock/virtio_transport_common.c
>+++ b/net/vmw_vsock/virtio_transport_common.c
>@@ -316,6 +316,15 @@ static struct sk_buff *virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *
> info->flags,
> zcopy);
>
>+ /*
>+ * If there is no corresponding socket, then we don't have a
>+ * corresponding namespace. This only happens For VIRTIO_VSOCK_OP_RST.
>+ */

So, in virtio_transport_recv_pkt() should we check that `net` is not
set?

Should we set it to NULL here?

>+ if (vsk) {
>+ virtio_vsock_skb_set_net(skb, info->net);

Ditto here about the net refcnt, can the net disappear?
Should we use get_net() in some way, or the socket will prevent that?

>+ virtio_vsock_skb_set_net_mode(skb, vsk->net_mode);
>+ }
>+
> return skb;
> out:
> kfree_skb(skb);
>@@ -527,6 +536,7 @@ static int virtio_transport_send_credit_update(struct vsock_sock *vsk)
> struct virtio_vsock_pkt_info info = {
> .op = VIRTIO_VSOCK_OP_CREDIT_UPDATE,
> .vsk = vsk,
>+ .net = sock_net(sk_vsock(vsk)),
> };
>
> return virtio_transport_send_pkt_info(vsk, &info);
>@@ -1067,6 +1077,7 @@ int virtio_transport_connect(struct vsock_sock *vsk)
> struct virtio_vsock_pkt_info info = {
> .op = VIRTIO_VSOCK_OP_REQUEST,
> .vsk = vsk,
>+ .net = sock_net(sk_vsock(vsk)),
> };
>
> return virtio_transport_send_pkt_info(vsk, &info);
>@@ -1082,6 +1093,7 @@ int virtio_transport_shutdown(struct vsock_sock *vsk, int mode)
> (mode & SEND_SHUTDOWN ?
> VIRTIO_VSOCK_SHUTDOWN_SEND : 0),
> .vsk = vsk,
>+ .net = sock_net(sk_vsock(vsk)),
> };
>
> return virtio_transport_send_pkt_info(vsk, &info);
>@@ -1108,6 +1120,7 @@ virtio_transport_stream_enqueue(struct vsock_sock *vsk,
> .msg = msg,
> .pkt_len = len,
> .vsk = vsk,
>+ .net = sock_net(sk_vsock(vsk)),
> };
>
> return virtio_transport_send_pkt_info(vsk, &info);
>@@ -1145,6 +1158,7 @@ static int virtio_transport_reset(struct vsock_sock *vsk,
> .op = VIRTIO_VSOCK_OP_RST,
> .reply = !!skb,
> .vsk = vsk,
>+ .net = sock_net(sk_vsock(vsk)),
> };
>
> /* Send RST only if the original pkt is not a RST pkt */
>@@ -1465,6 +1479,7 @@ virtio_transport_send_response(struct vsock_sock *vsk,
> .remote_port = le32_to_cpu(hdr->src_port),
> .reply = true,
> .vsk = vsk,
>+ .net = sock_net(sk_vsock(vsk)),
> };
>
> return virtio_transport_send_pkt_info(vsk, &info);
>@@ -1578,7 +1593,9 @@ static bool virtio_transport_valid_type(u16 type)
> void virtio_transport_recv_pkt(struct virtio_transport *t,
> struct sk_buff *skb)
> {
>+ enum vsock_net_mode net_mode = virtio_vsock_skb_net_mode(skb);
> struct virtio_vsock_hdr *hdr = virtio_vsock_hdr(skb);
>+ struct net *net = virtio_vsock_skb_net(skb);

Okay, so this is where the skb net is read, so why we touch the
virtio-vsock driver (virtio_transport.c) in the other patch where we
changed just af_vsock.c?

IMO we should move that change here, or in a separate commit.
Or maybe I missed some dependency :-)

Thanks,
Stefano

> struct sockaddr_vm src, dst;
> struct vsock_sock *vsk;
> struct sock *sk;
>@@ -1606,9 +1623,9 @@ void virtio_transport_recv_pkt(struct virtio_transport *t,
> /* The socket must be in connected or bound table
> * otherwise send reset back
> */
>- sk = vsock_find_connected_socket(&src, &dst);
>+ sk = vsock_find_connected_socket_net(&src, &dst, net, net_mode);
> if (!sk) {
>- sk = vsock_find_bound_socket(&dst);
>+ sk = vsock_find_bound_socket_net(&dst, net, net_mode);
> if (!sk) {
> (void)virtio_transport_reset_no_sock(t, skb);
> goto free_pkt;
>
>--
>2.47.3
>