From mboxrd@z Thu Jan  1 00:00:00 1970
From: Tom Lendacky <thomas.lendacky@amd.com>
Subject: Re: [RFC Part1 PATCH v3 02/17] x86/CPU/AMD: Add the Secure Encrypted
 Virtualization CPU feature
Date: Wed, 9 Aug 2017 13:17:54 -0500
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To: Borislav Petkov <bp@suse.de>
Cc: linux-efi@vger.kernel.org, Brijesh Singh <brijesh.singh@amd.com>, kvm@vger.kernel.org, =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= <rkrcmar@redhat.com>, Matt Fleming <matt@codeblueprint.co.uk>, David Howells <dhowells@redhat.com>, Paul Mackerras <paulus@samba.org>, "H . Peter Anvin" <hpa@zytor.com>, Christoph Lameter <cl@linux.com>, Jonathan Corbet <corbet@lwn.net>, x86@kernel.org, Piotr Luc <piotr.luc@intel.com>, Ingo Molnar <mingo@redhat.com>, Dave Airlie <airlied@redhat.com>, Laura Abbott <labbott@redhat.com>, Fenghua Yu <fenghua.yu@intel.com>, Kees Cook <keescook@chromium.org>, Arnd Bergmann <arnd@arndb.de>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, Reza Arbab <arbab@linux.vnet.ibm.com>, Andy Lutomirski <luto@kernel.org>, Thomas Gleixner <tglx@linutronix.de>, Tony Luck <tony.luck@intel.com>, Ard Biesheuvel <ard.biesheuvel@linaro.org>, linux-kernel@vger.kernel.org, Eric
List-Id: linux-efi@vger.kernel.org

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.
>