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

On Thu, Oct 18, 2018 at 11:08:34AM -0600, Jim Fehlig wrote: > 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? Yes, you are right - any pair of (os_type, arch) should be unique in the capabilities XML. So all machines should be reported in the same block.