[RFC PATCH 06/15] x86/microcode: Update the Intel processor flag scan check

[Sohil Mehta]

The check whether to read IA32_PLATFORM_ID MSR is misleading. It doesn't
seem to consider family while comparing the model number. This works
because init_intel_microcode() bails out if the processor family is less
than 6. It is better to update the current check to specifically include
family 6.

Ideally, a VFM check would make it more readable. But, there isn't a
macro to derive VFM from sig.

Signed-off-by: Sohil Mehta <sohil.mehta@xxxxxxxxx>
---
 arch/x86/kernel/cpu/microcode/intel.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c
index f3d534807d91..734819a12d5f 100644
--- a/arch/x86/kernel/cpu/microcode/intel.c
+++ b/arch/x86/kernel/cpu/microcode/intel.c
@@ -74,7 +74,8 @@ void intel_collect_cpu_info(struct cpu_signature *sig)
 	sig->pf = 0;
 	sig->rev = intel_get_microcode_revision();
 
-	if (x86_model(sig->sig) >= 5 || x86_family(sig->sig) > 6) {
+	/* TODO: Simplify this using a VFM check? */
+	if ((x86_family(sig->sig) == 6 && x86_model(sig->sig) >= 5) || x86_family(sig->sig) > 6) {
 		unsigned int val[2];
 
 		/* get processor flags from MSR 0x17 */
-- 
2.43.0