Re: [Qemu-devel] [PATCH v3 4/6] qemu-option: support +foo/-foo command line agruments

[Alexey Kardashevskiy]

On 11/13/2013 12:11 AM, Igor Mammedov wrote:
> On Tue, 12 Nov 2013 23:39:27 +1100
> Alexey Kardashevskiy <address@hidden> wrote:
> 
>> On 12.11.2013 20:58, Igor Mammedov wrote:
>>> On Tue, 12 Nov 2013 10:49:58 +1100
>>> Alexey Kardashevskiy <address@hidden> wrote:
>>>
>>>> On 11/12/2013 01:25 AM, Igor Mammedov wrote:
>>>>> On Mon, 11 Nov 2013 13:41:05 +0100
>>>>> Andreas Färber <address@hidden> wrote:
>>>>>
>>>>>> Am 11.11.2013 08:44, schrieb Alexey Kardashevskiy:
>>>>>>> This converts +foo/-foo to "foo=on"/"foo=off" respectively when
>>>>>>> QEMU parser is used for the command line options.
>>>>>>>
>>>>>>> "-cpu" parsers in x86 and other architectures should be unaffected
>>>>>>> by this change.
>>>>>>>
>>>>>>> Signed-off-by: Alexey Kardashevskiy <address@hidden>
>>>>>>> ---
>>>>>>>  util/qemu-option.c | 6 ++++++
>>>>>>>  1 file changed, 6 insertions(+)
>>>>>>>
>>>>>>> diff --git a/util/qemu-option.c b/util/qemu-option.c
>>>>>>> index efcb5dc..6c8667c 100644
>>>>>>> --- a/util/qemu-option.c
>>>>>>> +++ b/util/qemu-option.c
>>>>>>> @@ -890,6 +890,12 @@ static int opts_do_parse(QemuOpts *opts, const 
>>>>>>> char *params,
>>>>>>>                  if (strncmp(option, "no", 2) == 0) {
>>>>>>>                      memmove(option, option+2, strlen(option+2)+1);
>>>>>>>                      pstrcpy(value, sizeof(value), "off");
>>>>>>> +                } else if (strncmp(option, "-", 1) == 0) {
>>>>>>> +                    memmove(option, option+1, strlen(option+1)+1);
>>>>>>> +                    pstrcpy(value, sizeof(value), "off");
>>>>>>> +                } else if (strncmp(option, "+", 1) == 0) {
>>>>>>> +                    memmove(option, option+1, strlen(option+1)+1);
>>>>>>> +                    pstrcpy(value, sizeof(value), "on");
>>>>>>>                  } else {
>>>>>>>                      pstrcpy(value, sizeof(value), "on");
>>>>>>>                  }
>>>>>>
>>>>>> This looks like an interesting idea! However this is much too big a
>>>>>> change to just CC ppc folks on...
>>>>>>
>>>>>> Jan, I wonder if this might break slirp's hostfwd option?
>>>>>>
>>>>>> Not sure what other options potentially starting with '-' might be
>>>>>> affected. Test cases would be a helpful way of demonstrating that this
>>>>>> change does not have undesired side effects.
>>>>> on x86 there is several value fixups for compatibility reason and a manual
>>>>> value parsing in cpu_x86_parse_featurestr(), so above won't just work 
>>>>> there.
>>>>
>>>>
>>>> What particular x86 CPU option cannot be handled the way as PPC's "VSX" is
>>>> handled two patches below? As I see, even static properties will work there
>>>> fine.
>>> There is legacy code that is kept for CLI compatibility reasons.
>>> Please, look at following features in cpu_x86_parse_featurestr():
>>>   xlevel, tsc-freq hv-spinlocks
>>
>> Ok, I do not know for sure if static properties support setters/getters
>> (they do not if I remember correct) but what does prevent these x86
>> properties from being _dynamic_?
> nothing, except of:
>  * it's better to keep CPU device model clean from legacy hacks so that legacy
>    silent fixups of invalid values won't be available via other interfaces
>    except of CLI. That will force users to use correct property names/values
>    and not break old users that use legacy CLI options.
>
>>> the rest feature flags on x86 should be handled just fine by your patch,
>>> once x86properties series is applied. 
>>>
>>> that's why we are talking about parser hook that could be overridden
>>> by target if necessary.
>>
>> This part confuses me the most. I thought I added the hook and I did not
>> change other than PPC archs so my patches should have gone quite easily
>> to upstream but instead I was told (I think I was but I could
>> misunderstand) that other folks may be unhappy that my stuff does not
>> support +foo/-foo (which could be added later).
>>
>> Could you please point me to the x86properties patch(es) which everybody
>> is waiting for? Thanks!
> latest is available at
> https://github.com/imammedo/qemu/tree/x86-cpu-properties.v10.1
> which basically is a rebase with fixed conflicts of v9
> http://comments.gmane.org/gmane.comp.emulators.qemu/222284


Wow. This explains a lot. Thanks. Is there any plan to use QemuOpts for all
of this, instead of cpu_x86_parse_featurestr()?


-- 
Alexey