Re: [PATCH] target-i386: Improve x86_cpu_list output

[Jan Kiszka <jan.kiszka@web.de>]

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On 2013-02-27 08:37, Igor Mammedov wrote:
> On Wed, 27 Feb 2013 00:26:38 -0300
> Eduardo Habkost <ehabkost@redhat.com> wrote:
> 
>> On Tue, Feb 26, 2013 at 10:57:56PM +0100, Igor Mammedov wrote:
>>> On Sat, 23 Feb 2013 16:45:00 +0100
>>> Jan Kiszka <jan.kiszka@web.de> wrote:
>>>
>>>> From: Jan Kiszka <jan.kiszka@siemens.com>
>>>>
>>>> Several issues fixed:
>>>>  - We were missing a bunch of feature lists. Fix this by simply dumping
>>>>    the meta list feature_word_info.
>>>>  - kvm_enabled() cannot be true at this point because accelerators are
>>>>    initialized much later during init. Simply dump unconditionally.
>>> Why not to move list_cpu after accelerators are initialized?
>>
>> Because help output is simply documentation and shouldn't depend on any
>> other config option parsing or accelerator initialization at all?
> Don't see reason why it shouldn't.
> It's not a man page but a program and can do pretty much everything.

Actually, requiring "-enable-kvm -cpu ?" to list the host type would be
counterproductive - hardly any user will find this out, at best by
chance. However ...

> 
>>
>>>
>>>>  - Add explanation for "host" CPU type.
>>>>
>>>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>>>> ---
>>>>  target-i386/cpu.c |   20 +++++++++-----------
>>>>  1 files changed, 9 insertions(+), 11 deletions(-)
>>>>
>>>> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
>>>> index dfcf86e..6e742f0 100644
>>>> --- a/target-i386/cpu.c
>>>> +++ b/target-i386/cpu.c
>>>> @@ -1453,18 +1453,16 @@ void x86_cpu_list(FILE *f, fprintf_function cpu_fprintf)
>>>>          snprintf(buf, sizeof(buf), "%s", def->name);
>>>>          (*cpu_fprintf)(f, "x86 %16s  %-48s\n", buf, def->model_id);
>>>>      }
>>>> -    if (kvm_enabled()) {
>>>> -        (*cpu_fprintf)(f, "x86 %16s\n", "[host]");
>>>> -    }
>>>> +    (*cpu_fprintf)(f, "x86 %16s  %-48s\n", "host",
>>>> +                   "KVM processor with all supported host features");
>>>> +
>>> that would make 'host' visible to users even if QEMU compiled without KVM
>>> support. No big harm, but autotest could get confused when it gets 'host' CPU
>>> but QEMU doesn't run because it's not really supported.
>>
>> Then we have to fix the autotest test code to not try it without KVM.
>> :-)
>>
>> Help output is not a probing mechanism (although we often misuse it as
>> if it were), and I expect help output to be static and not depend on any
>> subsystem initialization.
> Then fix help output and add to "host" line something like " is available with
> -enable-kvm on command line and if your build was compiled --enable-kvm
> configure option", otherwise 'host' is misleading.
> Now even without 'host' in output of -cpu 'help', question why 'host' is not
> found periodically pops up on IRC. This change will just increase frequency of
> it.

...I will add "(only available in KVM mode)" here and wrap these lines
in #ifdef CONFIG_KVM. That should be more acceptable, no?

Jan



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