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

From: Tom Lendacky
Date: Wed Aug 09 2017 - 14:23:07 EST


On 7/25/2017 10:33 AM, Borislav Petkov wrote:
On Tue, Jul 25, 2017 at 10:29:40AM -0500, Tom Lendacky wrote:
But early_identify_cpu() calls get_cpu_cap() which will check for cpuid
leaf 0x80000008 support and set x86_phys_bits.

Right, but it can't be less than 32, can it? And if it is more than 32
bits, then it probably doesn't really matter on 32-bit. Unless it is
less than 36 bits and you do PAE...

I'll try to build and run a 32-bit kernel and see how this all flows.

Yeah, that would be good.

Ok, finally got around to running a 32-bit kernel and it reports
x86_phys_bits as 48.

Thanks,
Tom


Thanks.