path: root/drivers/xen/xenbus/xenbus_probe.c
diff options
authorStefano Stabellini <stefano.stabellini@eu.citrix.com>2010-05-17 17:08:21 +0100
committerJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>2010-07-22 16:46:09 -0700
commit183d03cc4ff39e0f0d952c09aa96d0abfd6e0c3c (patch)
tree75947fc4a9ac69e902663c9cb618993b7c656cff /drivers/xen/xenbus/xenbus_probe.c
parentx86/xen: event channels delivery on HVM. (diff)
xen: Xen PCI platform device driver.
Add the xen pci platform device driver that is responsible for initializing the grant table and xenbus in PV on HVM mode. Few changes to xenbus and grant table are necessary to allow the delayed initialization in HVM mode. Grant table needs few additional modifications to work in HVM mode. The Xen PCI platform device raises an irq every time an event has been delivered to us. However these interrupts are only delivered to vcpu 0. The Xen PCI platform interrupt handler calls xen_hvm_evtchn_do_upcall that is a little wrapper around __xen_evtchn_do_upcall, the traditional Xen upcall handler, the very same used with traditional PV guests. When running on HVM the event channel upcall is never called while in progress because it is a normal Linux irq handler (and we cannot switch the irq chip wholesale to the Xen PV ones as we are running QEMU and might have passed in PCI devices), therefore we cannot be sure that evtchn_upcall_pending is 0 when returning. For this reason if evtchn_upcall_pending is set by Xen we need to loop again on the event channels set pending otherwise we might loose some event channel deliveries. Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Sheng Yang <sheng@linux.intel.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Diffstat (limited to 'drivers/xen/xenbus/xenbus_probe.c')
1 files changed, 17 insertions, 5 deletions
diff --git a/drivers/xen/xenbus/xenbus_probe.c b/drivers/xen/xenbus/xenbus_probe.c
index d96fa75b45ec..a9e83c438cbb 100644
--- a/drivers/xen/xenbus/xenbus_probe.c
+++ b/drivers/xen/xenbus/xenbus_probe.c
@@ -781,8 +781,23 @@ void xenbus_probe(struct work_struct *unused)
/* Notify others that xenstore is up */
blocking_notifier_call_chain(&xenstore_chain, 0, NULL);
-static int __init xenbus_probe_init(void)
+static int __init xenbus_probe_initcall(void)
+ if (!xen_domain())
+ return -ENODEV;
+ if (xen_initial_domain() || xen_hvm_domain())
+ return 0;
+ xenbus_probe(NULL);
+ return 0;
+static int __init xenbus_init(void)
int err = 0;
@@ -834,9 +849,6 @@ static int __init xenbus_probe_init(void)
goto out_unreg_back;
- if (!xen_initial_domain())
- xenbus_probe(NULL);
* Create xenfs mountpoint in /proc for compatibility with
@@ -857,7 +869,7 @@ static int __init xenbus_probe_init(void)
return err;