From c81fb4e4a35cbee4f373387c4ed527676f6dc4b1 Mon Sep 17 00:00:00 2001 From: Andrew Cooper Date: Wed, 1 Apr 2020 15:52:43 +0100 Subject: [PATCH] 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 --- xen/arch/x86/cpu/microcode/intel.c | 4 +--- 1 file changed, 1 insertion(+), 3 deletions(-) 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); -- 2.30.2