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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v5 2/3] 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@xxxxxxxx>
Acked-by: Anthony PERARD <anthony.perard@xxxxxxxxxx>
---
V4: don't allow guest reading the new directory as requested by
Anthony Perard
V3: Added .backend_register function to XenDevOps in order to have a
way to let the backend decide whether all prerequisites are met
for support.
V2: update commit message as requested by Stefano
---
hw/xen/xen_backend.c | 63 ++++++++++++++++++++++++++++++++++++++++++++
hw/xen/xen_devconfig.c | 52 ++----------------------------------
include/hw/xen/xen_backend.h | 2 ++
3 files changed, 67 insertions(+), 50 deletions(-)
diff --git a/hw/xen/xen_backend.c b/hw/xen/xen_backend.c
index 60575ad..c63f9df 100644
--- a/hw/xen/xen_backend.c
+++ b/hw/xen/xen_backend.c
@@ -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);
}
diff --git a/hw/xen/xen_devconfig.c b/hw/xen/xen_devconfig.c
index 1f30fe4..b7d290d 100644
--- a/hw/xen/xen_devconfig.c
+++ b/hw/xen/xen_devconfig.c
@@ -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;
}
diff --git a/include/hw/xen/xen_backend.h b/include/hw/xen/xen_backend.h
index b4b4ff0..63364f7 100644
--- a/include/hw/xen/xen_backend.h
+++ b/include/hw/xen/xen_backend.h
@@ -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);
--
2.6.6
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