The CPUID instruction is expensive. No point executing it twice when once
will do fine.
Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
---
CC: Jan Beulich <jbeul...@suse.com>
CC: Wei Liu <w...@xen.org>
CC: Roger Pau Monné <roger....@citrix.com>
---
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);
--
2.11.0
