linux-kernel - Re: [PATCH 2/2] x86/cpu: clear SME/SEV/SEV

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Message-ID: <470a6b50-9af5-b098-da52-4e3470be8e8f@amd.com>
Date:   Fri, 11 Feb 2022 14:42:19 -0600
From:   Tom Lendacky <thomas.lendacky@....com>
To:     "Limonciello, Mario" <mario.limonciello@....com>,
        Borislav Petkov <bp@...en8.de>,
        "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>
Cc:     Kees Cook <keescook@...omium.org>, hughsient@...il.com,
        Martin Fernandez <martin.fernandez@...ypsium.com>,
        linux-kernel@...r.kernel.org, Brijesh Singh <brijesh.singh@....com>
Subject: Re: [PATCH 2/2] x86/cpu: clear SME/SEV/SEV_ES features when not in
 use

On 2/11/22 13:54, Limonciello, Mario wrote:
> On 2/11/2022 08:46, Tom Lendacky wrote:
>> +Brijesh (please copy him, too, on all SEV related things)
>>
>> On 2/10/22 23:36, Mario Limonciello wrote:
>>> Currently SME/SEV/SEV_ES features are reflective of whether the CPU
>>> supports the features but not whether they have been activated by the
>>> kernel.
>>>
>>> Change this around to clear the features if the kernel is not using
>>> them so userspace can determine if they are available and in use
>>> from `/proc/cpuinfo`.
>>>
>>> Signed-off-by: Mario Limonciello <mario.limonciello@....com>

> 
> Maybe it's best then to just check for/clear the SME feature at this time 
> and let Brijesh handle plumbing the applicable removals/additions for 
> SEV/SEV_ES separately.
> 

Yes, probably SME only is good for now.

Thanks,
Tom