[Xen-devel] [PATCH] pvops: Avoid re-alloc_intr_gate of hvm evtchn callback

[Frank Pan <frankpzh@xxxxxxxxx>]

I've met a issue that a PV-on-HVM domain become stucked after migration.
The alloc_intr_gate(HVM_XEN_EVTCHN_CALLBACK) is called the second time
after the migration and leads to BUG(). (The first time is at system
initialization)

The following patch fixes this by check whether this callback is
registered or not before calling alloc_intr_gate.
---
 linux-2.6-xen/drivers/xen/events.c |    4 +++-
 1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/linux-2.6-xen/drivers/xen/events.c
b/linux-2.6-xen/drivers/xen/events.c
index ac7b42f..77ffceb 100644
--- a/linux-2.6-xen/drivers/xen/events.c
+++ b/linux-2.6-xen/drivers/xen/events.c
@@ -1500,7 +1500,9 @@ void xen_callback_vector(void)
                }
                printk(KERN_INFO "Xen HVM callback vector for event delivery is 
"
                                "enabled\n");
-               alloc_intr_gate(XEN_HVM_EVTCHN_CALLBACK, 
xen_hvm_callback_vector);
+               /* xen_callback_vector will be called after every domU resume */
+               if (!test_bit(XEN_HVM_EVTCHN_CALLBACK, used_vectors))
+                       alloc_intr_gate(XEN_HVM_EVTCHN_CALLBACK, 
xen_hvm_callback_vector);
        }
 }
 #else
-- 
1.7.0.4


-- 
潘震皓, Frank Pan

Computer Science and Technology
Tsinghua University

0001-Avoid-re-alloc_intr_gate-of-hvm-evtchn-callback.patch
Description: Text Data

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