9p: add virtio transport

This adds a transport to 9p for communicating between guests and a host
using a virtio based transport.

Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>

Author: ericvh

Documentation/filesystems/9p.txt

@@ -42,10 +42,12 @@ OPTIONS
 
   trans=name	select an alternative transport.  Valid options are
   		currently:
- 			unix - specifying a named pipe mount point
- 			tcp  - specifying a normal TCP/IP connection
- 			fd   - used passed file descriptors for connection
+			unix 	- specifying a named pipe mount point
+			tcp	- specifying a normal TCP/IP connection
+			fd   	- used passed file descriptors for connection
                                 (see rfdno and wfdno)
+			virtio	- connect to the next virtio channel available
+				(from lguest or KVM with trans_virtio module)
 
   uname=name	user name to attempt mount as on the remote server.  The
   		server may override or ignore this value.  Certain user

include/linux/virtio_9p.h

@@ -0,0 +1,10 @@
+#ifndef _LINUX_VIRTIO_9P_H
+#define _LINUX_VIRTIO_9P_H
+#include <linux/virtio_config.h>
+
+/* The ID for virtio console */
+#define VIRTIO_ID_9P	9
+/* Maximum number of virtio channels per partition (1 for now) */
+#define MAX_9P_CHAN	1
+
+#endif /* _LINUX_VIRTIO_9P_H */

net/9p/Kconfig

@@ -23,6 +23,13 @@ config NET_9P_FD
 	  file descriptors.  TCP/IP is the default transport for 9p,
 	  so if you are going to use 9p, you'll likely want this.
 
+config NET_9P_VIRTIO
+	depends on NET_9P && EXPERIMENTAL && VIRTIO
+	tristate "9P Virtio Transport (Experimental)"
+	help
+	  This builds support for a transports between
+	  guest partitions and a host partition.
+
 config NET_9P_DEBUG
 	bool "Debug information"
 	depends on NET_9P

net/9p/Makefile

@@ -1,5 +1,6 @@
 obj-$(CONFIG_NET_9P) := 9pnet.o
 obj-$(CONFIG_NET_9P_FD) += 9pnet_fd.o
+obj-$(CONFIG_NET_9P_VIRTIO) += 9pnet_virtio.o
 
 9pnet-objs := \
 	mod.o \
@@ -12,3 +13,6 @@ obj-$(CONFIG_NET_9P_FD) += 9pnet_fd.o
 
 9pnet_fd-objs := \
 	trans_fd.o \
+
+9pnet_virtio-objs := \
+	trans_virtio.o \