[PATCH v5 05/16] qemu: Build command line for virtio-mem

[Michal Prívozník]

On 9/15/21 8:16 AM, Jing Qi wrote:
> Hi Michal,
> I tried to test the virtio-mem with upstream version v7.7.0-136-g9b49c2c6d3
> adding the current patch
> (with qemu-6.1.0-7.fc36.x86_64) -

Hey, thanks for that!

> 
> 
> <maxMemory slots='16' unit='KiB'>8388608</maxMemory>
>   <memory unit='KiB'>1179648</memory>
>   <currentMemory unit='KiB'>1179648</currentMemory>
>  <memoryBacking>
>     <allocation mode='immediate'/>
>   </memoryBacking>
>  ....
>   <cpu mode='custom' match='exact' check='none'>
>     <model fallback='forbid'>qemu64</model>
>     <numa>
>       <cell id='0' cpus='0-1' memory='1048576' unit='KiB' discard='yes'/>
>     </numa>
>   </cpu>
> ...
>  <memory model='virtio-mem'>
>       <source>
>         <nodemask>0</nodemask>
>         <pagesize unit='KiB'>2048</pagesize>
>       </source>
>       <target>
>         <size unit='KiB'>131072</size>
>         <node>0</node>
>         <block unit='KiB'>2048</block>
>         <requested unit='KiB'>131072</requested>
>       </target>
>       <address type='pci' domain='0x0000' bus='0x00' slot='0x03'
> function='0x0'/>
>     </memory>
> 
> The vm was started successfully and there was no "prealloc: true"  in the
> command line.
> But I also found when <allocation mode='immediate'/> was added in the
> domain and the "virtio-mem" device was not added, the qemu command line
> also didn't have "prealloc:true". Is this correct? This result is
> different in "libvirt-7.6.0-3.module+el8.5.0+12510+80564ecf.x86_64" &
> "qemu-kvm-6.0.0-29.module+el8.5.0+12386+43574bac.x86_64".

This doesn't sound correct. But I'm unable to reproduce locally. Can you
please share your domain XML that's failing?

Michal