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>
master
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

@ -42,11 +42,36 @@ struct xs_handle *xenstore = NULL;
const char *xen_protocol;
/* private */
struct xs_dirs {
char *xs_dir;
QTAILQ_ENTRY(xs_dirs) list;
};
static QTAILQ_HEAD(xs_dirs_head, xs_dirs) xs_cleanup =
QTAILQ_HEAD_INITIALIZER(xs_cleanup);
static QTAILQ_HEAD(XenDeviceHead, XenDevice) xendevs = QTAILQ_HEAD_INITIALIZER(xendevs);
static int debug = 0;
/* ------------------------------------------------------------- */
static void xenstore_cleanup_dir(char *dir)
{
struct xs_dirs *d;
d = g_malloc(sizeof(*d));
d->xs_dir = dir;
QTAILQ_INSERT_TAIL(&xs_cleanup, d, list);
}
void xen_config_cleanup(void)
{
struct xs_dirs *d;
QTAILQ_FOREACH(d, &xs_cleanup, list) {
xs_rm(xenstore, 0, d->xs_dir);
}
}
int xenstore_write_str(const char *base, const char *node, const char *val)
{
char abspath[XEN_BUFSIZE];
@ -75,6 +100,30 @@ char *xenstore_read_str(const char *base, const char *node)
return ret;
}
int xenstore_mkdir(char *path, int p)
{
struct xs_permissions perms[2] = {
{
.id = 0, /* set owner: dom0 */
}, {
.id = xen_domid,
.perms = p,
}
};
if (!xs_mkdir(xenstore, 0, path)) {
xen_be_printf(NULL, 0, "xs_mkdir %s: failed\n", path);
return -1;
}
xenstore_cleanup_dir(g_strdup(path));
if (!xs_set_permissions(xenstore, 0, path, perms, 2)) {
xen_be_printf(NULL, 0, "xs_set_permissions %s: failed\n", path);
return -1;
}
return 0;
}
int xenstore_write_int(const char *base, const char *node, int ival)
{
char val[12];
@ -726,6 +775,20 @@ err:
int xen_be_register(const char *type, struct XenDevOps *ops)
{
char path[50];
int rc;
if (ops->backend_register) {
rc = ops->backend_register();
if (rc) {
return rc;
}
}
snprintf(path, sizeof(path), "device-model/%u/backends/%s", xen_domid,
type);
xenstore_mkdir(path, XS_PERM_NONE);
return xenstore_scan(type, xen_domid, ops);
}

View File

@ -5,54 +5,6 @@
/* ------------------------------------------------------------- */
struct xs_dirs {
char *xs_dir;
QTAILQ_ENTRY(xs_dirs) list;
};
static QTAILQ_HEAD(xs_dirs_head, xs_dirs) xs_cleanup = QTAILQ_HEAD_INITIALIZER(xs_cleanup);
static void xen_config_cleanup_dir(char *dir)
{
struct xs_dirs *d;
d = g_malloc(sizeof(*d));
d->xs_dir = dir;
QTAILQ_INSERT_TAIL(&xs_cleanup, d, list);
}
void xen_config_cleanup(void)
{
struct xs_dirs *d;
QTAILQ_FOREACH(d, &xs_cleanup, list) {
xs_rm(xenstore, 0, d->xs_dir);
}
}
/* ------------------------------------------------------------- */
static int xen_config_dev_mkdir(char *dev, int p)
{
struct xs_permissions perms[2] = {{
.id = 0, /* set owner: dom0 */
},{
.id = xen_domid,
.perms = p,
}};
if (!xs_mkdir(xenstore, 0, dev)) {
xen_be_printf(NULL, 0, "xs_mkdir %s: failed\n", dev);
return -1;
}
xen_config_cleanup_dir(g_strdup(dev));
if (!xs_set_permissions(xenstore, 0, dev, perms, 2)) {
xen_be_printf(NULL, 0, "xs_set_permissions %s: failed\n", dev);
return -1;
}
return 0;
}
static int xen_config_dev_dirs(const char *ftype, const char *btype, int vdev,
char *fe, char *be, int len)
{
@ -66,8 +18,8 @@ static int xen_config_dev_dirs(const char *ftype, const char *btype, int vdev,
snprintf(be, len, "%s/backend/%s/%d/%d", dom, btype, xen_domid, vdev);
free(dom);
xen_config_dev_mkdir(fe, XS_PERM_READ | XS_PERM_WRITE);
xen_config_dev_mkdir(be, XS_PERM_READ);
xenstore_mkdir(fe, XS_PERM_READ | XS_PERM_WRITE);
xenstore_mkdir(be, XS_PERM_READ);
return 0;
}

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);