On Fri, Aug 30, 2013 at 04:51:20PM +0200, Andreas Färber wrote: > 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 <ehabk...@redhat.com> > > Reviewed-by: liguang <lig.f...@cn.fujitsu.com> > > --- > > 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. :)
In case anybody wants to verify it: compile it before/after applying the patch, with: make CFLAGS='-save-temps -DNDEBUG and save x86_64-softmmu/cpu.s file from each run. You are going to see some differences between both files due to __LINE__ being used as argument to object*_dynamic_cast_assert(), but nothing else. -- Eduardo
