virtio-serial-bus: Add a port 'name' property for port discovery in guests
The port 'id' or number is internal state between the guest kernel and
our bus implementation. This is invocation-dependent and isn't part of
the guest-host ABI.
To correcly enumerate and map ports between the host and the guest, the
'name' property is used.
Example:
-device virtserialport,name=org.qemu.port.0
This invocation will get us a char device in the guest at:
/dev/virtio-ports/org.qemu.port.0
which can be a symlink to
/dev/vport0p3
This 'name' property is exposed by the guest kernel in a sysfs
attribute:
/sys/kernel/virtio-ports/vport0p3/name
A simple udev script can pick up this name and create the symlink
mentioned above.
Signed-off-by: Amit Shah <[email protected]>
Signed-off-by: Anthony Liguori <[email protected]>
diff --git a/hw/virtio-serial.h b/hw/virtio-serial.h
index d9c7acb..28ea7da 100644
--- a/hw/virtio-serial.h
+++ b/hw/virtio-serial.h
@@ -50,6 +50,7 @@
#define VIRTIO_CONSOLE_CONSOLE_PORT 1
#define VIRTIO_CONSOLE_RESIZE 2
#define VIRTIO_CONSOLE_PORT_OPEN 3
+#define VIRTIO_CONSOLE_PORT_NAME 4
/* == In-qemu interface == */
@@ -84,6 +85,13 @@
VirtQueue *ivq, *ovq;
/*
+ * This name is sent to the guest and exported via sysfs.
+ * The guest could create symlinks based on this information.
+ * The name is in the reverse fqdn format, like org.qemu.console.0
+ */
+ char *name;
+
+ /*
* This id helps identify ports between the guest and the host.
* The guest sends a "header" with this id with each data packet
* that it sends and the host can then find out which associated
