RE: [PATCH net-next 0/6] vsock: add local transport support

Jorgen Hansen
2019-11-21T14:45:38Z

> From: Stefano Garzarella [mailto:sgarzare@redhat.com]
> Sent: Tuesday, November 19, 2019 12:01 PM
> This series introduces a new transport (vsock_loopback) to handle
> local communication.
> This could be useful to test vsock core itself and to allow developers
> to test their applications without launching a VM.
>
> Before this series, vmci and virtio transports allowed this behavior,
> but only in the guest.
> We are moving the loopback handling in a new transport, because it
> might be useful to provide this feature also in the host or when
> no H2G/G2H transports (hyperv, virtio, vmci) are loaded.
>
> The user can use the loopback with the new VMADDR_CID_LOCAL (that
> replaces VMADDR_CID_RESERVED) in any condition.
> Otherwise, if the G2H transport is loaded, it can also use the guest
> local CID as previously supported by vmci and virtio transports.
> If G2H transport is not loaded, the user can also use VMADDR_CID_HOST
> for local communication.
>
> Patch 1 is a cleanup to build virtio_transport_common without virtio
> Patch 2 adds the new VMADDR_CID_LOCAL, replacing
> VMADDR_CID_RESERVED
> Patch 3 adds a new feature flag to register a loopback transport
> Patch 4 adds the new vsock_loopback transport based on the loopback
> implementation of virtio_transport
> Patch 5 implements the logic to use the local transport for loopback
> communication
> Patch 6 removes the loopback from virtio_transport
>
> @Jorgen: Do you think it might be a problem to replace
> VMADDR_CID_RESERVED with VMADDR_CID_LOCAL?

No, that should be fine. It has never allowed for use with stream sockets in
AF_VSOCK. The only potential use would be for datagram sockets, but that
side appears to be unaffected by your changes, since loopback is only
introduced for SOCK_STREAM.

>
> Thanks,
> Stefano
>
> Stefano Garzarella (6):
> vsock/virtio_transport_common: remove unused virtio header includes
> vsock: add VMADDR_CID_LOCAL definition
> vsock: add local transport support in the vsock core
> vsock: add vsock_loopback transport
> vsock: use local transport when it is loaded
> vsock/virtio: remove loopback handling
>
> MAINTAINERS | 1 +
> include/net/af_vsock.h | 2 +
> include/uapi/linux/vm_sockets.h | 8 +-
> net/vmw_vsock/Kconfig | 12 ++
> net/vmw_vsock/Makefile | 1 +
> net/vmw_vsock/af_vsock.c | 49 +++++-
> net/vmw_vsock/virtio_transport.c | 61 +------
> net/vmw_vsock/virtio_transport_common.c | 3 -
> net/vmw_vsock/vmci_transport.c | 2 +-
> net/vmw_vsock/vsock_loopback.c | 217
> ++++++++++++++++++++++++
> 10 files changed, 283 insertions(+), 73 deletions(-)
> create mode 100644 net/vmw_vsock/vsock_loopback.c
>
> --
> 2.21.0