[libvirt] [PATCH v4 2/5] libxl: add support for PVH

Jim Fehlig jfehlig at suse.com
Thu Oct 18 17:08:34 UTC 2018


On 10/17/18 12:59 PM, Marek Marczykowski-Górecki wrote:
> On Sat, Oct 13, 2018 at 08:46:19AM -0600, Jim Fehlig wrote:
>> I had some couch time at the start of the weekend and was finally able to
>> try using this series with virt-install. As it turns out, reporting
>> duplicate <guest> blocks for <os_type> 'xen' is not quite right. Instead we
>> will want to report the additional <machine> under the existing 'xen'
>> <guest> blocks.
> 
> Is that virt-install limitation? In that case, IMO virt-install should
> be fixed, instead of changing capabilities xml to match its limitations.

Perhaps it is a virt-install limitation, but my suggestion was based more on how 
the qemu driver reports the different machines

<guest>
   <os_type>hvm</os_type>
   <arch name='x86_64'>
     <wordsize>64</wordsize>
     <emulator>/usr/bin/qemu-system-x86_64</emulator>
     <machine maxCpus='255'>pc-i440fx-3.0</machine>
     <machine maxCpus='288'>pc-q35-3.0</machine>
     ...
   </arch>
</guest>

Compare that with reporting PV and PVH in different <guest> blocks, where the 
<os_type> and <arch> are the same. It seems confusing from a consumers POV

<guest>
   <os_type>xen</os_type>
   <arch name='x86_64'>
     <wordsize>64</wordsize>
     <emulator>/usr/bin/qemu-system-x86_64</emulator>
     <machine>xenpv</machine>
   </arch>
</guest>

<guest>
   <os_type>xen</os_type>
   <arch name='x86_64'>
     <wordsize>64</wordsize>
     <emulator>/usr/bin/qemu-system-x86_64</emulator>
     <machine>xenpvh</machine>
   </arch>
</guest>

How should a consumer interpret that? Is the machine for os_type=xen, 
arch=x86_64 a xenpv or a xenpvh?

Regards,
Jim




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