On Wed, Sep 16, 2026 at 02:44:28PM +0200, Stefano Garzarella wrote:
> On Tue, Sep 15, 2026 at 11:14:47AM -0700, Bobby Eshleman wrote:
> > On Tue, Sep 15, 2026 at 05:47:02PM +0200, Stefano Garzarella wrote:
> > > On Wed, Sep 02, 2026 at 04:00:49PM -0700, Bobby Eshleman wrote:
> > > > From: Bobby Eshleman <[email protected]>
> > > >
> > > > virtio-vsock did not have namespace support (the device was always
> > > > accessible to any global namespace).
> > > >
> > > > Make the virtio-vsock device assignable to a namespace and initialize it
> > > > to init_net. Because virtio-vsock and init_net are both hardcoded to
> > > > global mode, nothing changes until the assign ioctl is issued.
> > > >
> > > > When the device's local-mode namespace is being destroyed, received
> > > > packets are reset until new valid a namespace has been assigned and/or
> > > > automatically returned to, and the next RX batch begins (in
> > > > virtio_transport_rx_work). They are reset rather than dropped because
> > > > vsock does not retransmit, so a silent drop would leave the host waiting
> > > > for a timeout, and a connection request arriving in that window has no
> > > > socket whose teardown would tell it otherwise. This requires making
> > > > virtio_transport_reset_no_sock() available outside of the common code.
> > > >
> > > > When a device is assigned to a namespace, every already established
> > > > vsock socket that is no longer able to reach the device is forcibly
> > > > reset. For that reason, adding new sockets to the connected table must
> > > > be performed atomically with regards to namespace assignment. This
> > > > ensures that when the socket is added to the connected table that it
> > > > actually passes the new reachability conditions set by ns assignment. If
> > > > it wins the race to the table and does NOT pass the reachability tests,
> > > > then the reset sweep will correctly catch it. This is the purpose
> > > > of the new helper 'vsock_maybe_set_connected()'.
> > > >
> > > > Signed-off-by: Bobby Eshleman <[email protected]>
> > > > ---
> > > > include/linux/virtio_vsock.h            |  2 ++
> > > > net/vmw_vsock/virtio_transport.c        | 28 
> > > > ++++++++++++++++++++++------
> > > > net/vmw_vsock/virtio_transport_common.c | 28 
> > > > +++++++++++++++++++++-------
> > > > 3 files changed, 45 insertions(+), 13 deletions(-)
> > > >
> > > > diff --git a/include/linux/virtio_vsock.h b/include/linux/virtio_vsock.h
> > > > index f91704731057..9c68ce1d7fb4 100644
> > > > --- a/include/linux/virtio_vsock.h
> > > > +++ b/include/linux/virtio_vsock.h
> > > > @@ -286,6 +286,8 @@ void virtio_transport_inc_tx_pkt(struct 
> > > > virtio_vsock_sock *vvs, struct sk_buff *
> > > > u32 virtio_transport_get_credit(struct virtio_vsock_sock *vvs, u32 
> > > > wanted);
> > > > void virtio_transport_put_credit(struct virtio_vsock_sock *vvs, u32 
> > > > credit);
> > > > void virtio_transport_deliver_tap_pkt(struct sk_buff *skb);
> > > > +int virtio_transport_reset_no_sock(const struct virtio_transport *t,
> > > > +                                  struct sk_buff *skb, struct net 
> > > > *net);
> > > > int virtio_transport_purge_skbs(void *vsk, struct sk_buff_head *list);
> > > > int virtio_transport_read_skb(struct vsock_sock *vsk, skb_read_actor_t 
> > > > read_actor);
> > > > int virtio_transport_notify_set_rcvlowat(struct vsock_sock *vsk, int 
> > > > val);
> > > > diff --git a/net/vmw_vsock/virtio_transport.c 
> > > > b/net/vmw_vsock/virtio_transport.c
> > > > index 4f9aa9c4c3aa..a453a4f828dc 100644
> > > > --- a/net/vmw_vsock/virtio_transport.c
> > > > +++ b/net/vmw_vsock/virtio_transport.c
> > > > @@ -540,9 +540,14 @@ static bool 
> > > > virtio_transport_msgzerocopy_allow(void)
> > > >         return true;
> > > > }
> > > >
> > > > +static bool virtio_transport_netns_assign_allow(void)
> > > > +{
> > > > +       return true;
> > > > +}
> > > > +
> > > > bool virtio_transport_stream_allow(struct vsock_sock *vsk, u32 cid, u32 
> > > > port)
> > > > {
> > > > -       return vsock_net_mode_global(vsk);
> > > > +       return vsock_g2h_net_reachable(sock_net(sk_vsock(vsk)));
> > > > }
> > > >
> > > > static bool virtio_transport_seqpacket_allow(struct vsock_sock *vsk,
> > > > @@ -587,6 +592,7 @@ static struct virtio_transport virtio_transport = {
> > > >                 .seqpacket_has_data       = 
> > > > virtio_transport_seqpacket_has_data,
> > > >
> > > >                 .msgzerocopy_allow        = 
> > > > virtio_transport_msgzerocopy_allow,
> > > > +               .netns_assign_allow       = 
> > > > virtio_transport_netns_assign_allow,
> > > >
> > > >                 .notify_poll_in           = 
> > > > virtio_transport_notify_poll_in,
> > > >                 .notify_poll_out          = 
> > > > virtio_transport_notify_poll_out,
> > > > @@ -616,7 +622,7 @@ virtio_transport_seqpacket_allow(struct vsock_sock 
> > > > *vsk, u32 remote_cid)
> > > >         struct virtio_vsock *vsock;
> > > >         bool seqpacket_allow;
> > > >
> > > > -       if (!vsock_net_mode_global(vsk))
> > > > +       if (!vsock_g2h_net_reachable(sock_net(sk_vsock(vsk))))
> > > >                 return false;
> > > >
> > > >         seqpacket_allow = false;
> > > > @@ -634,6 +640,9 @@ static void virtio_transport_rx_work(struct 
> > > > work_struct *work)
> > > >         struct virtio_vsock *vsock =
> > > >                 container_of(work, struct virtio_vsock, rx_work);
> > > >         struct virtqueue *vq;
> > > > +       struct net *net;
> > > > +
> > > > +       net = vsock_g2h_net_get();
> > > >
> > > >         mutex_lock(&vsock->rx_lock);
> > > >
> > > > @@ -682,10 +691,14 @@ static void virtio_transport_rx_work(struct 
> > > > work_struct *work)
> > > >
> > > >                         virtio_transport_deliver_tap_pkt(skb);
> > > >
> > > > -                       /* Force virtio-transport into global mode 
> > > > since it
> > > > -                        * does not yet support local-mode namespacing.
> > > > -                        */
> > > > -                       virtio_transport_recv_pkt(&virtio_transport, 
> > > > skb, NULL);
> > > > +                       if (unlikely(!net)) {
> > > > +                               virtio_transport_reset_no_sock(
> > > > +                                       &virtio_transport, skb, 
> > > > &init_net);
> > > 
> > > Why init_net?
> > 
> > This parameter is actually unused by virtio_transport_reset_no_sock(),
> > its call to virtio_transport_send_pkt(), and even the eventual call to
> > virtio_transport_deliver_tap_pkt()... so maybe NULL w/ a comment would
> > be better?
> 
> mmm, should we remove that parameter if unused?

Sadly the vhost path uses it for its vhost_vsock lookup by CID. I guess
it would be needed by g2h too if it had multiple devices and had to
lookup by net+CID.

> 
> Anyway, not in this series/patch.
> 
> Here, anything is fine, just put a comment with the reason.


Sounds good!

Thanks,
Bobby

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