* Ashok Raj <ashok....@intel.com> wrote:
> After updating microcode on one of the threads in the core, the
> thread sibling automatically gets the update since the microcode
> resources are shared. Check the ucode revision on the cpu before
> performing a ucode update.
s/cpu/CPU
>
> Signed-off-by: Ashok Raj <ashok....@intel.com>
> Cc: X86 ML <x...@kernel.org>
> Cc: LKML <linux-kernel@vger.kernel.org>
> ---
> arch/x86/kernel/cpu/microcode/intel.c | 16 +++++++++++++---
> 1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/microcode/intel.c
> b/arch/x86/kernel/cpu/microcode/intel.c
> index 09b95a7..036d1db 100644
> --- a/arch/x86/kernel/cpu/microcode/intel.c
> +++ b/arch/x86/kernel/cpu/microcode/intel.c
> @@ -776,7 +776,7 @@ static enum ucode_state apply_microcode_intel(int cpu)
> {
> struct microcode_intel *mc;
> struct ucode_cpu_info *uci;
> - struct cpuinfo_x86 *c;
> + struct cpuinfo_x86 *c = &cpu_data(cpu);
> static int prev_rev;
> u32 rev;
>
> @@ -793,6 +793,18 @@ static enum ucode_state apply_microcode_intel(int cpu)
> return UCODE_NFOUND;
> }
>
> + rev = intel_get_microcode_revision();
> + /*
> + * Its possible the microcode got udpated
> + * because its sibling update was done earlier.
> + * Skip the udpate in that case.
> + */
> + if (rev >= mc->hdr.rev) {
> + uci->cpu_sig.rev = rev;
> + c->microcode = rev;
> + return UCODE_OK;
> + }
s/udpate
/update
Also, more fundamentally, during microcode early testing, isn't it possible for
internal iterations of the microcode to have the same revision, but be
different?
This patch would prevent re-loading it - for a seemingly minimal benefit.
Thanks,
Ingo
