Re: [PATCH] KVM: X86: Allow userspace to define the microcode version

Borislav Petkov
2018-02-26T19:37:34Z

On Mon, Feb 26, 2018 at 09:39:12AM -0500, Konrad Rzeszutek Wilk wrote:
> diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
> index d19e903214b4..87d044ce837f 100644
> --- a/arch/x86/kernel/cpu/intel.c
> +++ b/arch/x86/kernel/cpu/intel.c
> @@ -144,6 +144,13 @@ static bool bad_spectre_microcode(struct cpuinfo_x86 *c)
> {
> int i;
>
> + /*
> + * We know that the hypervisor lie to us on the microcode version so
> + * we may as well trust that it is running the correct version.
> + */
> + if (boot_cpu_has(X86_FEATURE_HYPERVISOR))

I guess

cpu_has(c, X86_FEATURE_HYPERVISOR)

since we're passing a ptr to the current CPU.

It boils down to the same thing in the end but this is bit nicer and
besides the rest of the code uses cpu_has() too.

Otherwise, yap, this looks like a good idea.

Thx.

--
Regards/Gruss,
Boris.

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