xen: enable console and disk backend in HVM mode

Initialize the Xen console backend and the Xen disk backend even when
running in HVM mode so that PV on HVM drivers can connect to them.
Signed-off-by: NStefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: NAlexander Graf <agraf@suse.de>

xen-all.c

@@ -862,6 +862,14 @@ int xen_hvm_init(void)
     cpu_register_phys_memory_client(&state->client);
     state->log_for_dirtybit = NULL;
 
+    /* Initialize backend core & drivers */
+    if (xen_be_init() != 0) {
+        fprintf(stderr, "%s: xen backend core setup failed\n", __FUNCTION__);
+        exit(1);
+    }
+    xen_be_register("console", &xen_console_ops);
+    xen_be_register("qdisk", &xen_blkdev_ops);
+
     return 0;
 }