xenbus: don't rely on xen_initial_domain to detect local xenstore
The xenstore daemon does not have to run in the xen initial domain;
however, Linux currently uses xen_initial_domain to test if a loopback
event channel should be used instead of the event channel provided in
Xen's start_info structure. Instead, if the event channel passed in the
start_info structure is not valid, assume that this domain will run
xenstored locally and set up the event channel.
Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Reviewed-by: Ian Campbell <Ian.Campbell@citrix.com>
Signed-off-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 d5347fe..13b0f05 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -696,64 +696,74 @@
device_initcall(xenbus_probe_initcall);
-static int __init xenbus_init(void)
+/* Set up event channel for xenstored which is run as a local process
+ * (this is normally used only in dom0)
+ */
+static int __init xenstored_local_init(void)
{
int err = 0;
unsigned long page = 0;
+ struct evtchn_alloc_unbound alloc_unbound;
- DPRINTK("");
+ /* Allocate Xenstore page */
+ page = get_zeroed_page(GFP_KERNEL);
+ if (!page)
+ goto out_err;
- err = -ENODEV;
+ 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 = DOMID_SELF;
+
+ err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
+ &alloc_unbound);
+ if (err == -ENOSYS)
+ goto out_err;
+
+ BUG_ON(err);
+ xen_store_evtchn = xen_start_info->store_evtchn =
+ alloc_unbound.port;
+
+ return 0;
+
+ out_err:
+ if (page != 0)
+ free_page(page);
+ return err;
+}
+
+static int __init xenbus_init(void)
+{
+ int err = 0;
+
if (!xen_domain())
- return err;
+ return -ENODEV;
- /*
- * Domain0 doesn't have a store_evtchn or store_mfn yet.
- */
- if (xen_initial_domain()) {
- struct evtchn_alloc_unbound alloc_unbound;
-
- /* Allocate Xenstore page */
- page = get_zeroed_page(GFP_KERNEL);
- if (!page)
+ if (xen_hvm_domain()) {
+ uint64_t v = 0;
+ err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
+ if (err)
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 = DOMID_SELF;
-
- err = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
- &alloc_unbound);
- if (err == -ENOSYS)
+ xen_store_evtchn = (int)v;
+ err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
+ if (err)
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);
+ xen_store_mfn = (unsigned long)v;
+ xen_store_interface = ioremap(xen_store_mfn << PAGE_SHIFT, PAGE_SIZE);
} else {
- if (xen_hvm_domain()) {
- uint64_t v = 0;
- err = hvm_get_parameter(HVM_PARAM_STORE_EVTCHN, &v);
- if (err)
- goto out_error;
- xen_store_evtchn = (int)v;
- err = hvm_get_parameter(HVM_PARAM_STORE_PFN, &v);
- if (err)
- goto out_error;
- xen_store_mfn = (unsigned long)v;
- xen_store_interface = ioremap(xen_store_mfn << PAGE_SHIFT, PAGE_SIZE);
- } else {
- xen_store_evtchn = xen_start_info->store_evtchn;
- xen_store_mfn = xen_start_info->store_mfn;
- xen_store_interface = mfn_to_virt(xen_store_mfn);
+ xen_store_evtchn = xen_start_info->store_evtchn;
+ xen_store_mfn = xen_start_info->store_mfn;
+ if (xen_store_evtchn)
xenstored_ready = 1;
+ else {
+ err = xenstored_local_init();
+ if (err)
+ goto out_error;
}
+ xen_store_interface = mfn_to_virt(xen_store_mfn);
}
/* Initialize the interface to xenstore. */
@@ -772,12 +782,7 @@
proc_mkdir("xen", NULL);
#endif
- return 0;
-
- out_error:
- if (page != 0)
- free_page(page);
-
+ out_error:
return err;
}