From: Andrew Cooper Date: Wed, 1 Apr 2020 14:52:43 +0000 (+0100) Subject: x86/ucode/intel: Remove one CPUID from collect_cpu_info() X-Git-Tag: archive/raspbian/4.14.0+80-gd101b417b7-1+rpi1^2~63^2~427 X-Git-Url: https://dgit.raspbian.org/?a=commitdiff_plain;h=c81fb4e4a35cbee4f373387c4ed527676f6dc4b1;p=xen.git x86/ucode/intel: Remove one CPUID from collect_cpu_info() The CPUID instruction is expensive. No point executing it twice when once will do fine. Signed-off-by: Andrew Cooper Reviewed-by: Jan Beulich --- diff --git a/xen/arch/x86/cpu/microcode/intel.c b/xen/arch/x86/cpu/microcode/intel.c index 72bd1ad0bc..f1e64e188b 100644 --- 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); /* get the current revision from MSR 0x8B */ rdmsrl(MSR_IA32_UCODE_REV, msr_content);