xen: Initialize xenbus for dom0.

Do initial xenbus/xenstore setup in dom0.  In dom0 we need to actually
allocate the xenstore resources, rather than being given them from
outside.

[ Impact: initialize Xenbus ]

Signed-off-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index d409495876f11b24fabaebc01d57f02224fe459f..d242610597c06445d0a311afed9b2bbb929728fe 100644 (file)
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -801,6 +801,7 @@ device_initcall(xenbus_probe_initcall);
 static int __init xenbus_init(void)
 {
        int err = 0;
+       unsigned long page = 0;
 
        DPRINTK("");
 
@@ -821,7 +822,31 @@ static int __init xenbus_init(void)
         * Domain0 doesn't have a store_evtchn or store_mfn yet.
         */
        if (xen_initial_domain()) {
-               /* dom0 not yet supported */
+               struct evtchn_alloc_unbound alloc_unbound;
+
+               /* Allocate Xenstore page */
+               page = get_zeroed_page(GFP_KERNEL);
+               if (!page)
+                       goto out_error;
+
+               xen_store_mfn = xen_start_info->store_mfn =
+                       pfn_to_mfn(virt_to_phys((void *)page) >>
+                                  PAGE_SHIFT);
+
+               /* Next allocate a local port which xenstored can bind to */
+               alloc_unbound.dom        = DOMID_SELF;
+               alloc_unbound.remote_dom = 0;
+
+               err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
+                                                 &alloc_unbound);
+               if (err == -ENOSYS)
+                       goto out_error;
+
+               BUG_ON(err);
+               xen_store_evtchn = xen_start_info->store_evtchn =
+                       alloc_unbound.port;
+
+               xen_store_interface = mfn_to_virt(xen_store_mfn);
        } else {
                if (xen_hvm_domain()) {
                        uint64_t v = 0;
@@ -867,6 +892,8 @@ static int __init xenbus_init(void)
        bus_unregister(&xenbus_frontend.bus);
 
   out_error:
+       if (page != 0)
+               free_page(page);
        return err;
 }