Re: [RFC Part1 PATCH v3 02/17] x86/CPU/AMD: Add the Secure Encrypted Virtualization CPU feature

Tom Lendacky
2017-07-25T15:29:40Z

On 7/25/2017 10:13 AM, Borislav Petkov wrote:
> On Tue, Jul 25, 2017 at 09:58:54AM -0500, Tom Lendacky wrote:
>> True, but it is more about being accurate and making sure the value is
>> correct where ever it may be used.
>
> So early_identify_cpu() initializes phys_bits to 32 on 32-bit.
> Subtracting it there would actually make actively it wrong, AFAICT.

But early_identify_cpu() calls get_cpu_cap() which will check for cpuid
leaf 0x80000008 support and set x86_phys_bits. I'll try to build and
run a 32-bit kernel and see how this all flows.

Thanks,
Tom

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