Re: [Qemu-devel] [PATCH 1/3] [x86] Clean up vendor identification

[Carlos A. M. dos Santos]

On Mon, Aug 11, 2008 at 9:32 AM, Alexander Graf <address@hidden> wrote:
>
> On Aug 11, 2008, at 1:56 PM, Laurent Vivier wrote:
>
>> Le lundi 11 août 2008 à 12:37 +0200, Alexander Graf a écrit :
>>>
>>> Right now CPU vendor identification contains a lot of magic numbers.
>>> The
>>> patch cleans them up to defines, so we can identify the CPU later on
>>> without copying magic numbers.
>>>
>>> Signed-off-by: Alexander Graf <address@hidden>
>>>
>>>
>>>
>>> diff --git a/qemu/target-i386/cpu.h b/qemu/target-i386/cpu.h
>>> index 7e95900..3c84dc9 100644
>>> --- a/qemu/target-i386/cpu.h
>>> +++ b/qemu/target-i386/cpu.h
>>> @@ -339,6 +341,14 @@
>>> #define CPUID_EXT3_IBS     (1 << 10)
>>> #define CPUID_EXT3_SKINIT  (1 << 12)
>>>
>>> +#define CPUID_VENDOR_INTEL_1 0x756e6547 /* "Genu" */
>>> +#define CPUID_VENDOR_INTEL_2 0x49656e69 /* "ineI" */
>>> +#define CPUID_VENDOR_INTEL_3 0x6c65746e /* "ntel" */
>>> +
>>> +#define CPUID_VENDOR_AMD_1   0x68747541 /* "Auth" */
>>> +#define CPUID_VENDOR_AMD_2   0x69746e65 /* "enti" */
>>> +#define CPUID_VENDOR_AMD_3   0x444d4163 /* "cAMD" */
>>
>> if you add "-Wno-multichar" in C flags, you can use:
>>
>> #define CPUID_VENDOR_INTEL_1 'Genu'
>> ...
>
> Is that a real improvement? It won't make the code faster and the
> readability doesn't improve that much either.

I'd take it as a security improvement. One can easily commit a typo
when editting magic numbers, either decimal or hexa.

-- 
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