[PATCH RESEND v1] xen: recognize device_model_override

[Jim Fehlig]

On 11/12/20 11:03 AM, Olaf Hering wrote:
> Since Xen 4.2 libxl expects device_model_override="/path" instead of
> device_model="/path".

This has been on my todo list but never got the priority it deserved. Thanks for 
taking it on. Without your patch, using 'xl create' on xl.cfg converted from 
domXML by the libxl driver results in

WARNING: ignoring device_model directive.
WARNING: Use "device_model_override" instead if you really want a non-default 
device_model

> Adjust the code to parse this as <emulator>.

You also have to adjust all the failing {xl,xm}configtests.

> While libxl also recognizes device_model_version="", this knob is not
> supported by libvirt. A runtime detection exists to select either
> "qemu-xen" or "qemu-xen-traditional".

Correct. It is selected based on the specified <emulator> and not modeled in 
domXML. Does it need to be exposed to the user? AFAIK those are the only two 
values we care about, and it is possible to determine which to use based on the 
<emulator>.

Regards,
Jim

> 
> Signed-off-by: Olaf Hering <olaf at aepfle.de>
> ---
>   src/libxl/xen_common.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/src/libxl/xen_common.c b/src/libxl/xen_common.c
> index c82e487d80..88a784ed04 100644
> --- a/src/libxl/xen_common.c
> +++ b/src/libxl/xen_common.c
> @@ -1508,7 +1508,7 @@ xenParseConfigCommon(virConfPtr conf,
>       if (xenParseTimeOffset(conf, def) < 0)
>           return -1;
>   
> -    if (xenConfigCopyStringOpt(conf, "device_model", &def->emulator) < 0)
> +    if (xenConfigCopyStringOpt(conf, "device_model_override", &def->emulator) < 0)
>           return -1;
>   
>       if (STREQ(nativeFormat, XEN_CONFIG_FORMAT_XL)) {
> @@ -2242,7 +2242,7 @@ static int
>   xenFormatEmulator(virConfPtr conf, virDomainDefPtr def)
>   {
>       if (def->emulator &&
> -        xenConfigSetString(conf, "device_model", def->emulator) < 0)
> +        xenConfigSetString(conf, "device_model_override", def->emulator) < 0)
>           return -1;
>   
>       return 0;
>