xen: write information about supported backends

Add a Xenstore directory for each supported pv backend. This will allow
Xen tools to decide which backend type to use in case there are
multiple possibilities.

The information is added under
/local/domain/<backend-domid>/device-model/<domid>/backends
before the "running" state is written to Xenstore. Using a directory
for each backend enables us to add parameters for specific backends
in the future.

This interface is documented in the Xen source repository in the file
docs/misc/qemu-backends.txt

In order to reuse the Xenstore directory creation already present in
hw/xen/xen_devconfig.c move the related functions to
hw/xen/xen_backend.c where they fit better.

Signed-off-by: Juergen Gross <jgross@suse.com>
Acked-by: Anthony PERARD <anthony.perard@citrix.com>
Reviewed-by: Wei Liu <wei.liu2@citrix.com>
Message-id: 1463062421-613-3-git-send-email-jgross@suse.com
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
This commit is contained in:
Juergen Gross 2016-05-12 16:13:40 +02:00 committed by Gerd Hoffmann
parent 9432e53a5b
commit 637c53ffcb
3 changed files with 67 additions and 50 deletions

View file

@ -28,6 +28,7 @@ struct XenDevOps {
int (*free)(struct XenDevice *xendev);
void (*backend_changed)(struct XenDevice *xendev, const char *node);
void (*frontend_changed)(struct XenDevice *xendev, const char *node);
int (*backend_register)(void);
};
struct XenDevice {
@ -63,6 +64,7 @@ extern const char *xen_protocol;
extern DeviceState *xen_sysdev;
/* xenstore helper functions */
int xenstore_mkdir(char *path, int p);
int xenstore_write_str(const char *base, const char *node, const char *val);
int xenstore_write_int(const char *base, const char *node, int ival);
int xenstore_write_int64(const char *base, const char *node, int64_t ival);