From mboxrd@z Thu Jan  1 00:00:00 1970
From: jonkery huang <jonkery.huang@oracle.com>
Subject: Redhat enterprise linux 4 update 7 guest suspend hang
Date: Tue, 22 Jul 2008 17:35:36 +0800
Message-ID: <4885A9E8.4030702@oracle.com>
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Hi,

I have installed a Redhat EL4U7 HVM guest, then issue xm suspend, the 
command will hang at xc_save:
1. # ps aux
......
root     16761  0.1  0.9  11264  5984 pts/9    S+   14:17   0:00 python
/usr/sbin/xm suspend 41
root     16763  0.0  0.0   1988   480 ?        S    14:17   0:00
/usr/lib/xen/bin/xc_save 29 41 0 0 4

# strace -p 16763
Process 16763 attached - interrupt to quit
read(0,

seems it is waiting for something.

2. Check with this guest, it has pv dirver installed:
# xm li
Name                                        ID   Mem VCPUs      State   
Time(s)
Domain-0                                     0   585     4     r-----   
1144.9
OVM_EL4U7_X86_HVM_4GB                       40  1024     1     
-b----     82.2

# python
Python 2.4.3 (#1, Jun  6 2007, 15:09:38)
[GCC 4.1.1 20070105 (Red Hat 4.1.1-52)] on linux2
Type "help", "copyright", "credits" or "license" for more information.
 >>> import sys
 >>> import xen.lowlevel.xc
 >>> from xen.xend.XendConstants import *
 >>> xc = xen.lowlevel.xc.xc()
 >>> hvm_pvdrv = xc.hvm_get_param(40, HVM_PARAM_CALLBACK_IRQ) 
 >>> if hvm_pvdrv:
...     print "This domain has PV drivers"  
...
This domain has PV drivers

3. Check with EL4U7 kernel kernel-2.6.9-70.0.0.0.1.EL, 
HVM_PARAM_CALLBACK_IRQ is set when init platform-pci which is built in 
to the kernel.

4. For hvm guest with pv driver, xend will deal with it in a special 
way, paste some code from tools/python/xen/xend/XendDomainInfo.py
        # HVM domain shuts itself down only if it has PV drivers
        if self.info.is_hvm():
            hvm_pvdrv = xc.hvm_get_param(self.domid, HVM_PARAM_CALLBACK_IRQ)
            if not hvm_pvdrv:
                code = REVERSE_DOMAIN_SHUTDOWN_REASONS[reason]
                log.info("HVM save:remote shutdown dom %d!", self.domid)
                xc.domain_shutdown(self.domid, code)

In the comment, it says "HVM domain shuts itself down only if it has PV 
drivers", what does this mean? how to shutdown a HVM guest with pv driver?

-- 
Thanks
Jonkery