On 02.04.2020 12:18, Andrew Cooper wrote: > The CPUID instruction is expensive. No point executing it twice when once > will do fine. > > Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
Reviewed-by: Jan Beulich <jbeul...@suse.com> albeit ... > --- a/xen/arch/x86/cpu/microcode/intel.c > +++ b/xen/arch/x86/cpu/microcode/intel.c > @@ -121,14 +121,12 @@ static int collect_cpu_info(struct cpu_signature *csig) > > memset(csig, 0, sizeof(*csig)); > > - csig->sig = cpuid_eax(0x00000001); > - > rdmsrl(MSR_IA32_PLATFORM_ID, msr_content); > csig->pf = 1 << ((msr_content >> 50) & 7); > > wrmsrl(MSR_IA32_UCODE_REV, 0x0ULL); > /* As documented in the SDM: Do a CPUID 1 here */ > - cpuid_eax(1); > + csig->sig = cpuid_eax(1); ... with this, perhaps make the title say "remove one CPUID ..." or some such? Jan
