Re: [Qemu-devel] [PATCH v4 02/18] target-i386: Simplify reporting of unavailable features

["Andreas Färber" <afaerber@suse.de>]

Am 15.05.2014 15:39, schrieb Eduardo Habkost:
> On Thu, May 15, 2014 at 02:21:12PM +0200, Andreas Färber wrote:
>> Am 30.04.2014 18:48, schrieb Eduardo Habkost:
>>> Instead of checking and calling unavailable_host_feature() once for each
>>> bit, simply call the function (now renamed to
>>> report_unavailable_features()) once for each feature word.
>>>
>>> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
>>> ---
>>> Changes v1 -> v2:
>>>  * Rebase to latest qom-cpu (commit 90c5d39c)
>>> Changes v2 -> v3:
>>>  * Trivial rebase after QEMU 2.0 (onto commit 2d03b49)
>>> ---
>>>  target-i386/cpu.c | 16 +++++++---------
>>>  1 file changed, 7 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/target-i386/cpu.c b/target-i386/cpu.c
>>> index 7ec706f..9cd0039 100644
>>> --- a/target-i386/cpu.c
>>> +++ b/target-i386/cpu.c
>>> @@ -1236,11 +1236,11 @@ static const TypeInfo host_x86_cpu_type_info = {
>>>  
>>>  #endif
>>>  
>>> -static int unavailable_host_feature(FeatureWordInfo *f, uint32_t mask)
>>> +static int report_unavailable_features(FeatureWordInfo *f, uint32_t mask)
>>>  {
>>>      int i;
>>>  
>>> -    for (i = 0; i < 32; ++i)
>>> +    for (i = 0; i < 32; ++i) {
>>>          if (1 << i & mask) {
>>>              const char *reg = get_register_name_32(f->cpuid_reg);
>>>              assert(reg);
>>> @@ -1249,8 +1249,8 @@ static int unavailable_host_feature(FeatureWordInfo *f, uint32_t mask)
>>>                  f->cpuid_eax, reg,
>>>                  f->feat_names[i] ? "." : "",
>>>                  f->feat_names[i] ? f->feat_names[i] : "", i);
>>> -            break;
>>>          }
>>> +    }
>>>      return 0;
>>>  }
>>>  
>>> @@ -1274,12 +1274,10 @@ static int kvm_check_features_against_host(KVMState *s, X86CPU *cpu)
>>>          uint32_t host_feat = kvm_arch_get_supported_cpuid(s, wi->cpuid_eax,
>>>                                                               wi->cpuid_ecx,
>>>                                                               wi->cpuid_reg);
>>> -        uint32_t mask;
>>> -        for (mask = 1; mask; mask <<= 1) {
>>> -            if (guest_feat & mask && !(host_feat & mask)) {
>>> -                unavailable_host_feature(wi, mask);
>>> -                rv = 1;
>>> -            }
>>> +        uint32_t unavailable_features = guest_feat & ~host_feat;
>>> +        if (unavailable_features) {
>>> +            report_unavailable_features(wi, unavailable_features);
>>> +            rv = 1;
>>>          }
>>>      }
>>>      return rv;
>>
>> Both before and after your patch the return value is never checked.
>> Shall we/I change it to void?
> 
> I will change this on my tree, but feel free to change my patch before
> applying, if you prefer.

I had inserted a patch and will squash it then, no need to resend.

Andreas

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