From mboxrd@z Thu Jan  1 00:00:00 1970
From: Arun Sharma <arun.sharma@intel.com>
Subject: Re: VMX device models not getting created anymore?
Date: Fri, 17 Jun 2005 12:28:46 -0700
Message-ID: <42B3246E.3000706@intel.com>
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To: Mike Wray <mike.wray@hp.com>
Cc: Ian Pratt <m+Ian.Pratt@cl.cam.ac.uk>, xen-devel@lists.xensource.com
List-Id: xen-devel@lists.xenproject.org

Mike Wray wrote:
> Compared to which field is it off by 1?
> The VMX code creates its own event channel using  
> channel.eventChannel(), which will
> allocate new ports. Possibly it should be reusing the existing control 
> channel port
> instead? This might account for the off-by-one as ports are allocated 
> sequentially.

That seems to be the problem. If I add some logging, I see:

[2005-06-17 12:06:07 xend] INFO (channel:32) created event channel: 
<EventChannel dom1:0:19 dom2:5:2>
[2005-06-17 12:06:07 xend] INFO (channel:32) created event channel: 
<EventChannel dom1:0:20 dom2:5:3>

The first one is created here:

File "/usr/lib/python/xen/xend/XendDomain.py", line 276, in domain_create
     dominfo = XendDomainInfo.create(self.dbmap, config)
   File "/usr/lib/python/xen/xend/XendDomainInfo.py", line 159, in create
     vm.construct(config)
   File "/usr/lib/python/xen/xend/XendDomainInfo.py", line 501, in construct
     self.construct_image()
   File "/usr/lib/python/xen/xend/XendDomainInfo.py", line 547, in 
construct_image
     self.create_channel()
   File "/usr/lib/python/xen/xend/XendDomainInfo.py", line 680, in 
create_channel
     self.store_channel = self.eventChannel("store_channel")
   File "/usr/lib/python/xen/xend/XendDomainInfo.py", line 674, in 
eventChannel
     return EventChannel.restoreFromDB(db, 0, self.id)
   File "/usr/lib/python/xen/xend/server/channel.py", line 59, in 
restoreFromDB
     evtchn = cls.interdomain(dom1, dom2, port1=port1, port2=port2)

The second is created here:

File "/usr/lib/python/xen/xend/XendDomain.py", line 276, in domain_create
     dominfo = XendDomainInfo.create(self.dbmap, config)
   File "/usr/lib/python/xen/xend/XendDomainInfo.py", line 159, in create
     vm.construct(config)
   File "/usr/lib/python/xen/xend/XendDomainInfo.py", line 502, in construct
     self.configure()
   File "/usr/lib/python/xen/xend/XendDomainInfo.py", line 884, in configure
     self.create_devices()
   File "/usr/lib/python/xen/xend/XendDomainInfo.py", line 704, in 
create_devices
     self.image.createDeviceModel()
   File "/usr/lib/python/xen/xend/image.py", line 300, in createDeviceModel
     self.device_channel = channel.eventChannel(0, self.vm.getDomain())
   File "/usr/lib/python/xen/xend/server/channel.py", line 116, in 
eventChannel
     return EventChannel.interdomain(dom1, dom2, port1=port1, port2=port2)

Things get more interesting, because self.device_channel['port1'] for 
the second channel returns 19 instead of 20.

Are there assumptions in the code that there must be only one 
interdomain event channel between two domains?

	-Arun