diff mbox series

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

Message ID 20241220213711.1892696-7-sohil.mehta@intel.com (mailing list archive)
State New
Headers show
Series Prepare for new Intel family models | expand

Commit Message

Sohil Mehta Dec. 20, 2024, 9:37 p.m. UTC
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@intel.com>
---
 arch/x86/kernel/cpu/microcode/intel.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Borislav Petkov Dec. 21, 2024, 9:11 a.m. UTC | #1
On Fri, Dec 20, 2024 at 09:37:01PM +0000, Sohil Mehta wrote:
> 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@intel.com>
> ---
>  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? */

No TODOs. Take your time and do it right from the get-go please.
diff mbox series

Patch

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 */