Re: [PATCH] target/s390x: query-cpu-definitions filter deprecated features

[Markus Armbruster <armbru@redhat.com>]

Collin Walling <walling@linux.ibm.com> writes:

> Part of the query-cpu-definitions return payload includes an array of
> of "unavailable-features" which helps determine if the CPU model is
> compatible with the system's configuration.  When a KVM guest is
> using a CPU model with deprecated features disabled,
> query-cpu-definitions will claim that certain models are incompatible
> due to these features missing.
>
> Since deprecated features are preferred to be disabled for s390 CPU
> models, lets filter them out from the "missing" features list.
>
> Signed-off-by: Collin Walling <walling@linux.ibm.com>
> ---
>
> Examples output of query-cpu-definitions ran on a gen17a host:
>
> WithOUT patch:
>
> ```
> {
>   "return": [
>     {
>       "name": "z13",
>       "typename": "z13-s390x-cpu",
>       "unavailable-features": [
>         "csske"
>       ],
>       "static": false,
>       "migration-safe": true,
>       "deprecated": false
>     },
>     ...
> ```
>
> WITH patch:
>
> ```
> {
>   "return": [
>     {
>       "name": "z13",
>       "typename": "z13-s390x-cpu",
>       "unavailable-features": [],
>       "static": false,
>       "migration-safe": true,
>       "deprecated": false
>     },
>     ...
> ```

I'd put this right into the commit message.

Possibly stupid question (I know nothing about the subject matter): any
compatibility ramifications?  Does the change need to be tied to machine
type version?