On 09/08/2023 1:29 pm, Jan Beulich wrote: > Since as a bug workaround (likely inapplicable to any 64-bit CPUs, but > it probably doesn't hurt to keep this) we clear %ecx on input anyway, > we can as well fall back to cpuid_count(). This allows getting rid of > four risky casts and makes things type-safe. The latter aspect requires > two type adjustments elsewhere. While adjusting init_intel_cacheinfo(), > convert three other local variables there as well. For the struct > cpuinfo_x86 change it is relevant to note that no 64-bit CPU comes > without CPUID support, and hence cpuid_level is never set to -1; the > comment there was simply stale. > > No functional change intended, yet of course generated code isn't > identical. > > Signed-off-by: Jan Beulich <jbeul...@suse.com>
Hmm, far less invasive than when I last tried this, but that was years ago. > --- a/xen/arch/x86/include/asm/processor.h > +++ b/xen/arch/x86/include/asm/processor.h > @@ -131,13 +131,8 @@ static inline int cpu_nr_siblings(unsign > * clear %ecx since some cpus (Cyrix MII) do not set or clear %ecx > * resulting in stale register contents being returned. > */ > -#define cpuid(_op,_eax,_ebx,_ecx,_edx) \ > - asm volatile ( "cpuid" \ > - : "=a" (*(int *)(_eax)), \ > - "=b" (*(int *)(_ebx)), \ > - "=c" (*(int *)(_ecx)), \ > - "=d" (*(int *)(_edx)) \ > - : "0" (_op), "2" (0) ) > +#define cpuid(op, eax, ebx, ecx, edx) \ > + cpuid_count(op, 0, eax, ebx, ecx, edx) Can we swap op for leaf seeing as both are changing? Preferably with that changed, Acked-by: Andrew Cooper <andrew.coop...@citrix.com>
