Re: [Qemu-devel] [PATCH v2] i386: Use #defines instead of magic numbers for CPUID cache information

[Andreas Färber]

Am 27.08.2013 17:24, schrieb Eduardo Habkost:
> This is an attempt to make the CPUID cache topology code clearer, by
> replacing the magic numbers in the code with #defines, and moving all
> the cache information to the same place in the file.
> 
> I took care of comparing the assembly output of compiling
> target-i386/cpu.c before and after applying this change, to make sure
> not a single bit was changed on cpu_x86_cpuid() before and after
> applying this patch (unfortunately I had to manually check existing
> differences, because of __LINE__ expansions on
> object_class_dynamic_cast_assert() calls).
> 
> This even keeps the code bug-compatible with the previous version: today
> the cache information returned on AMD cache information leaves (CPUID
> 0x80000005 & 0x80000006) do not match the information returned on CPUID
> leaves 2 and 4. The L2 cache information on CPUID leaf 2 also doesn't
> match the information on CPUID leaf 2. The new constants should make it
> easier to eventually fix those inconsistencies. All inconsistencies I
> have found are documented in code comments.
> 
> Signed-off-by: Eduardo Habkost <address@hidden>
> Reviewed-by: liguang <address@hidden>
> ---
> Changes v1 -> v2:
>  * s/leafs/leaves/ on code comments
> ---
>  target-i386/cpu.c | 184 
> +++++++++++++++++++++++++++++++++++++++++++++++-------
>  1 file changed, 162 insertions(+), 22 deletions(-)

I think this is a good idea and the code looked sane, but it is unclear
to me from v1 whether Li Guang has verified as part of his review that
all the bits match the original ones or just that Coding Style and
general idea is okay?

I'm therefore holding off applying this one for today's pull, waiting
until either someone confirms Eduardo's results or I find the time to do
so myself, the former being appreciated. :)

Regards,
Andreas

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