Subject: Re: [RFC PATCH v3 04/20] x86: Handle reduction in physical address
 size with SME
To: Borislav Petkov <bp@alien8.de>
References: <20161110003426.3280.2999.stgit@tlendack-t1.amdoffice.net>
 <20161110003513.3280.12104.stgit@tlendack-t1.amdoffice.net>
 <20161115121035.GD24857@8bytes.org> <20161115121456.f4slpk4i2jl3e2ke@pd.tnic>
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 <20161115213312.lrtejyv4x7nzvzsp@pd.tnic>
CC: Joerg Roedel <joro@8bytes.org>, <linux-arch@vger.kernel.org>,
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From: Tom Lendacky <thomas.lendacky@amd.com>
Message-ID: <25496e6a-ddf0-231a-f83d-cdc2f61e6d96@amd.com>
Date: Tue, 15 Nov 2016 16:01:45 -0600
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On 11/15/2016 3:33 PM, Borislav Petkov wrote:
> On Tue, Nov 15, 2016 at 03:22:45PM -0600, Tom Lendacky wrote:
>> Hmmm... I still need the ebx value from the CPUID instruction to
>> calculate the proper reduction in physical bits, so I'll still need
>> to make the CPUID call.
> 
>         if (c->extended_cpuid_level >= 0x8000001f) {
>                 cpuid(0x8000001f, &eax, &ebx, &ecx, &edx);
> 
> 		...
> 
> just like the rest of get_cpu_cap() :)

Right, which is what the code does now.  I was looking at switching
over to the cpu_has() function and eliminate the cpuid call, but I
still need the cpuid call for the ebx value.

Thanks,
Tom

>