xen/sysfs: Use XENVER_guest_handle to query UUID
This hypercall has been present since Xen 3.1, and is the preferred
method for a domain to obtain its UUID. Fall back to the xenstore method
if using an older version of Xen (which returns -ENOSYS).
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
diff --git a/drivers/xen/sys-hypervisor.c b/drivers/xen/sys-hypervisor.c
index fdb6d22..5e5ad7e2 100644
--- a/drivers/xen/sys-hypervisor.c
+++ b/drivers/xen/sys-hypervisor.c
@@ -114,7 +114,7 @@
/* UUID */
-static ssize_t uuid_show(struct hyp_sysfs_attr *attr, char *buffer)
+static ssize_t uuid_show_fallback(struct hyp_sysfs_attr *attr, char *buffer)
{
char *vm, *val;
int ret;
@@ -135,6 +135,17 @@
return ret;
}
+static ssize_t uuid_show(struct hyp_sysfs_attr *attr, char *buffer)
+{
+ xen_domain_handle_t uuid;
+ int ret;
+ ret = HYPERVISOR_xen_version(XENVER_guest_handle, uuid);
+ if (ret)
+ return uuid_show_fallback(attr, buffer);
+ ret = sprintf(buffer, "%pU\n", uuid);
+ return ret;
+}
+
HYPERVISOR_ATTR_RO(uuid);
static int __init xen_sysfs_uuid_init(void)