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SubjectRe: [patch v3 2/7] x86/smp: Dont access non-existing CPUID leaf
On Thu, Jun 15, 2023 at 10:33:52PM +0200, Thomas Gleixner wrote:

> Subject: Re: [patch v3 2/7] x86/smp: Dont access non-existing CPUID leaf

"Do not access a non-existing... "

> From: Tony Battersby <tonyb@cybernetics.com>
>
> stop_this_cpu() tests CPUID leaf 0x8000001f::EAX unconditionally. CPUs
> return the content of the highest supported leaf when a non-existing leaf
> is read.

This should be:

"On Intel, querying an invalid extended CPUID leaf returns the values of the
maximum basic CPUID leaf. On AMD, invalid CPUID leafs return zeros."

Other than that:

Reviewed-by: Borislav Petkov (AMD) <bp@alien8.de>

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette

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