EVTCHNOP_send crash Windows

[wayne gong <wayne.gong@oracle.com>]

Hello there,

When I run migration test for my PV drivers, I find that EVTCHNOP_send 
hypercall crash windows with error code 0x7F (0x8...) 
http://msdn.microsoft.com/en-us/library/ff559244(v=VS.85).aspx 
<http://msdn.microsoft.com/en-us/library/ff559244%28v=VS.85%29.aspx> 
when system was migrated for more than 500 times. PV drivers can call it 
successfully for several times before crash when system is suspending or 
resuming. It always happens in some xenstore watch event callback 
routine. Such as read/write device state key or state key changing 
watcher callback routine. The hypercall didn't return from hypervisor 
but windows crashes. I've checked the xenstore base address from share 
info and parameter of that hyper call, looks like are fine. So which 
situation of that hypercall will crash windows? Which part I should 
double check in my PV drivers?

I am using WDK 7600.16385.1, Windows 7 X86, Xen 3.4.0.

BTW, seems that Windows 7 X64 works fine in migration test.

Thanks
Wayne