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

[Alexey Kardashevskiy <aik@ozlabs.ru>]

On 12.11.2013 20:58, Igor Mammedov wrote:
> On Tue, 12 Nov 2013 10:49:58 +1100
> Alexey Kardashevskiy <aik@ozlabs.ru> wrote:
> 
>> On 11/12/2013 01:25 AM, Igor Mammedov wrote:
>>> On Mon, 11 Nov 2013 13:41:05 +0100
>>> Andreas Färber <afaerber@suse.de> 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 <aik@ozlabs.ru>
>>>>> ---
>>>>>  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_?


> 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!

> PS:
> extending QemuOpts to parsing +/-opts format, seems like good workaround
> above problem. But I was under impression that general movement was to convert
> custom formats to canonical format "prop=value".

Heh. I do not understand movements in the qemu project most of the time
:) I thought I could have added "compat" to PowerPC CPU as others did
but I was so wrong :)



-- 
With best regards

Alexey Kardashevskiy -- icq: 52150396