Virtualization - Nov 2021 - [PATCH v2] virtio/vsock: fix the transport to work with VMADDR_CID_ANY

On Thu, Nov 25, 2021 at 08:18:23PM -0500, Wei Wang
wrote:
>The VMADDR_CID_ANY flag used by a socket means that the socket isn't
bound
>to any specific CID. For example, a host vsock server may want to be bound
>with VMADDR_CID_ANY, so that a guest vsock client can connect to the host
>server with CID=VMADDR_CID_HOST (i.e. 2), and meanwhile, a host vsock
>client can connect to the same local server with CID=VMADDR_CID_LOCAL
>(i.e. 1).
>
>The current implementation sets the destination socket's svm_cid to a
>fixed CID value after the first client's connection, which isn't an
>expected operation. For example, if the guest client first connects to the
>host server, the server's svm_cid gets set to VMADDR_CID_HOST, then
other
>host clients won't be able to connect to the server anymore.
>
>Reproduce steps:
>1. Run the host server:
>   socat VSOCK-LISTEN:1234,fork -
>2. Run a guest client to connect to the host server:
>   socat - VSOCK-CONNECT:2:1234
>3. Run a host client to connect to the host server:
>   socat - VSOCK-CONNECT:1:1234
>
>Without this patch, step 3. above fails to connect, and socat complains
>"socat[1720] E connect(5, AF=40 cid:1 port:1234, 16): Connection
>reset by peer".
>With this patch, the above works well.
>
>Fixes: c0cfa2d8a788 ("vsock: add multi-transports support")
>Signed-off-by: Wei Wang <wei.w.wang at intel.com>
>---
> net/vmw_vsock/virtio_transport_common.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
Usually fixes for net/vmw_vsock/* are applied through the net tree 
(netdev at vger.kernel.org) that seems not CCed. Please use 
./scripts/get_maintainer.pl next time.

Maybe this one can be queued by Michael, let's wait a bit, otherwise 
please resend CCing netdev and using "net" tag.

Anyway the patch LGTM:

Reviewed-by: Stefano Garzarella <sgarzare at redhat.com>

Hi Michael,

Do you plan to merge this patch through your tree?
If not, I'll resend to have it applied to the net tree.

Thanks,
Wei

On Friday, November 26, 2021 4:54 PM, Stefano Garzarella
wrote:
> On Thu, Nov 25, 2021 at 08:18:23PM -0500, Wei Wang wrote:
> >The VMADDR_CID_ANY flag used by a socket means that the socket
isn't
> >bound to any specific CID. For example, a host vsock server may want to
> >be bound with VMADDR_CID_ANY, so that a guest vsock client can connect
> >to the host server with CID=VMADDR_CID_HOST (i.e. 2), and meanwhile, a
> >host vsock client can connect to the same local server with
> >CID=VMADDR_CID_LOCAL (i.e. 1).
> >
> >The current implementation sets the destination socket's svm_cid to
a
> >fixed CID value after the first client's connection, which
isn't an
> >expected operation. For example, if the guest client first connects to
> >the host server, the server's svm_cid gets set to VMADDR_CID_HOST,
then
> >other host clients won't be able to connect to the server anymore.
> >
> >Reproduce steps:
> >1. Run the host server:
> >   socat VSOCK-LISTEN:1234,fork -
> >2. Run a guest client to connect to the host server:
> >   socat - VSOCK-CONNECT:2:1234
> >3. Run a host client to connect to the host server:
> >   socat - VSOCK-CONNECT:1:1234
> >
> >Without this patch, step 3. above fails to connect, and socat complains
> >"socat[1720] E connect(5, AF=40 cid:1 port:1234, 16): Connection
reset
> >by peer".
> >With this patch, the above works well.
> >
> >Fixes: c0cfa2d8a788 ("vsock: add multi-transports support")
> >Signed-off-by: Wei Wang <wei.w.wang at intel.com>
> >---
> > net/vmw_vsock/virtio_transport_common.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> 
> Usually fixes for net/vmw_vsock/* are applied through the net tree
> (netdev at vger.kernel.org) that seems not CCed. Please
> use ./scripts/get_maintainer.pl next time.
> 
> Maybe this one can be queued by Michael, let's wait a bit, otherwise
please
> resend CCing netdev and using "net" tag.
> 
> Anyway the patch LGTM:
> 
> Reviewed-by: Stefano Garzarella <sgarzare at redhat.com>