Re: [Qemu-devel] [PATCH 12/19] Add a query-cputypes command to QMP

[Markus Armbruster]

"Daniel P. Berrange" <address@hidden> writes:

> This adds a new QMP command called 'query-cputypes' to allow
> for discovery of CPU types known to the QEMU binary. This is
> intended to relpace the need to parse '-cpu ?', '-cpu ?model'
> and '-cpu ?dump'
>
> Most targets have a simple structure listing just the CPU
> model names (and optionally a 'description'), with room for
> future expansion of extra attributes against each model
>
>   {
>       "cputypes": {
>           "models": [
>               {
>                   "name": "arm926"
>               },
>               {
>                   "name": "arm946"
>               },
>               {
>                   "name": "arm1026"
>               },
>               ....
>           ]
>       }
>   }
>
> The sparc and x86 targets have extra architecture specific
> metatadata. These are in keys 'x86info' and 'sparcinfo'
> against each CPU model dict. These keys are repeated at the
> top level to give data about all allowed feature names
>
> A trimmed example:
>
> {
>     "cputypes": {
>         "models": [
>             {
>                 "name": "n270",
>                 "description": "Intel(R) Atom(TM) CPU N270   @ 1.60GHz",
>                 "x86info": {
>                     "xlevel": 2147483658,
>                     "family": 6,
>                     "vendor": "",
>                     "level": 5,
>                     "model": 28,
>                     "stepping": 2,
>                     "features": {
>                         "ext_edx": [
>                             "lahf_lm"
>                         ],
>                         "edx": [
>                             "pbe",
>                             "tm",
>                             "ht",
>                             "ss",
>                             "sse2",
>                             ...
>                         ]
>                     }
>                 }
>             }
>         ],
>         "x86info": {
>             "features": {
>                 "ext_edx": [
>                     21,
>                     20,
>                     "nodeid_msr",
>                     "cvt16",
>                     17,
>                     "fma4",
>                     15,
>                     14,
>                     "wdt",
>                     ....
>                 ]
>             }
>         }
>     }
> }
>
> No mapping to the legacy readline monitor is provided


An alternative to arch-specific keys with equally arch-specific values
would be a arch-independent key with a discriminated union value.

  {
      "cputypes": {
          "models": [
              {
                  "name": "n270",
                  "description": "Intel(R) Atom(TM) CPU N270   @ 1.60GHz",
                  "arch-info": {
                      "arch": "x86",
                      "xlevel": 2147483658,
                      "family": 6,
                      ...

Dunno.