Re: [PATCH v2] x86/microcode/intel: replace sync_core() with native_cpuid_reg(eax)
From: Greg KH
Date: Wed Apr 22 2020 - 04:27:46 EST
On Wed, Apr 22, 2020 at 11:17:59AM +0300, Evalds Iodzevics wrote:
> On Intel it is required to do CPUID(1) before reading the microcode
> revision MSR. Current code in 4.4 an 4.9 relies on sync_core() to call
> CPUID, unfortunately on 32 bit machines code inside sync_core() always
> jumps past CPUID instruction as it depends on data structure boot_cpu_data
> witch are not populated correctly so early in boot sequence.
>
> It depends on:
> commit 5dedade6dfa2 ("x86/CPU: Add native CPUID variants returning a single
> datum")
>
> This patch is for 4.4 but also should apply to 4.9
>
> Signed-off-by: Evalds Iodzevics <evalds.iodzevics@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> arch/x86/include/asm/microcode_intel.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
Thanks, much better, now queued up.
greg k-h