[PATCH v2] xen: recognize device_model_override

[Jim Fehlig]

On 11/20/20 5:29 AM, Olaf Hering wrote:
> Since Xen 4.2 libxl expects device_model_override="/path" instead of
> device_model="/path". Adjust the code to parse this as <emulator>.

If I understand the documentation correctly, we also need to provide 
device_model_version when specifying the override. From the xl.cfg man page:

device_model_override="PATH"
Override the path to the binary to be used as the device-model running in 
toolstack domain. The binary provided here MUST be consistent with the 
device_model_version which you have specified. You should not normally need to 
specify this option.

Is my interpretation correct?

> While libxl also recognizes device_model_version="", this knob is not
> required for libvirt. A runtime detection exists in libvirt to select
> either "qemu-xen" or "qemu-xen-traditional".
> Since qemu-xen-traditional is marked as supported just for stubdoms
> there is no need to handle it.
> 
> The tests were adjusted with this script:
> 
> for i in tests/xlconfigdata/*.cfg tests/xmconfigdata/*.cfg
> do
>    case "$i" in
>      *basic-hvm*) continue ;;
>      *cpu-shares-hvm*) continue ;;
>      *max-eventchannels-hvm*) continue ;;
>      *max-gntframes-hvm*) continue ;;
>      *moredevs-hvm*) continue ;;
>      *variable-clock-hvm*) continue ;;
>      *vnuma-hvm*) continue ;;
>    esac
> sed -i '
> s@^device_model[[:blank:]]@device_model_override @
> ' "$i"
> done
> for i in tests/libxlxml2domconfigdata/*.json
> do
>    case "$i" in
>      *basic-hvm*) continue ;;
>      *cpu-shares-hvm*) continue ;;
>      *max-eventchannels-hvm*) continue ;;
>      *max-gntframes-hvm*) continue ;;
>      *moredevs-hvm*) continue ;;
>      *variable-clock-hvm*) continue ;;
>      *vnuma-hvm*) continue ;;
>    esac
> sed -i '
> s@"device_model"@"device_model_override"@
> ' "$i"
> done

Thanks for providing the info, but I don't think it is needed in the commit 
message. Providing it as info below the '---' gives the tip for reviewers and 
avoids adding it to the the actual commit when pushing.

Regards,
Jim