[Libvir] Re: support for hvm guests

[Jim Fehlig]

Daniel Veillard wrote:

>  First sorry for being a bit late answering,
>
>On Fri, Apr 28, 2006 at 06:07:43PM -0600, Jim Fehlig wrote:
>  
>
>>Type 'bridge' can be valid for hvm guests.  Perhaps it is better to not 
>>expose ioemu in the XML for now as there will probably be changes in 
>>this area anyway.  We know the domain is type hvm, so just add 'ioemu:' 
>>where necessary when talking to xend/xenstore.  I'm currently thinking 
>>about the following XML for OS element when type is hvm:
>>
>><os>
>>   <type>hvm</type>
>>   <kernel>/usr/lib/xen/boot/hvmloader</kernel>
>>   <device_model>/usr/lib/xen/bin/qemu-dm</device_model>
>>   <boot dev='c'>
>>   <graphics type='vnc'>
>>   <cdrom dev='/dev/hdd'>
>></os>
>>    
>>
>
>  Hum, I agree with Karel on the use of <boot dev='c' />, that's not really
>a logical naming, can we avoid that and use more strcutured names like
>'/dev/hda' .
>  Also I don't understand why graphics and cdrom are not defined in the
><devices> section for example
>
>  <devices>
>    <disk type='block'>
>       <source dev='hdd'/>
>       <target dev='hdd'/>
>       <cdrom/>
>    </disk>
>    <graphic type='vnc'>
>    </graphic>
>  
>  </devices>
>
>  
>
>>boot, graphics, and cdrom elements are optional.
>>- boot: The device from which the guest should boot.  If not specified 
>>the guest will
>>            be booted from hard disk.  'a' = floppy, 'c' = hard disk, 
>>'d' = cdrom
>>    
>>
>
>  not fond of that
>
>  
>
>>- graphics: Graphics model to use for the guest.  Valid type attribute 
>>values are 'vnc'
>>                  and 'sdl'.  If not specified the guest will be 
>>launched with sdl.
>>    
>>
>
>  use a graphic element in the devices section instead, that way it
>stay structured. Also be make code which may allow to pass extra informations
>in the future as subelements, for example the vnc device may define
>authentication mechanism, and default resolution/depth may also be passed
>down in the future
>
>  
>
>>- cdrom: The cdrom device, e.g. '/dev/hdd', '/path/to/iso/plan9.iso'
>>    
>>
>
>  Well should be a disk device too, with an extra <cdrom/> subelement,
>and a source and a target as usual.
>
>  
>
>>The patch I'm currently working on assumes this XML format.  What do you 
>>think?
>>    
>>
>
>  that I would prefer thing to stay more in line with existing format 
>details from http://libvirt.org/format.html, it's just semantic sugar but
>design error there are usually a burden in the long term,
>  
>

OK, these are great comments that I will incorporate into the patch.

Currently I can get info on hvm domains but unable to create them.  The 
create request is sent to xend but then blocks reading from xend in 
xend_req().  No problem creating the domain using xm.  I have looked at 
the config coming into xend and it is identical between xm and 
virsh/libvirt.  Need to poke around xend and see why there is no 
response to the virsh/libvirt create request for hvm domains.

Thanks for the comments.
Jim