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Date:   Fri, 4 Feb 2022 11:12:04 -0600
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Subject: Re: [PATCH v6 6/6] drivers/node: Show in sysfs node's crypto
 capabilities
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To:     Borislav Petkov <bp@alien8.de>,
        "Limonciello, Mario" <mario.limonciello@amd.com>
Cc:     Martin Fernandez <martin.fernandez@eclypsium.com>,
        linux-kernel@vger.kernel.org, linux-efi@vger.kernel.org,
        platform-driver-x86@vger.kernel.org, linux-mm@kvack.org,
        tglx@linutronix.de, mingo@redhat.com, dave.hansen@linux.intel.com,
        x86@kernel.org, hpa@zytor.com, ardb@kernel.org,
        dvhart@infradead.org, andy@infradead.org,
        gregkh@linuxfoundation.org, rafael@kernel.org, rppt@kernel.org,
        akpm@linux-foundation.org, daniel.gutson@eclypsium.com,
        hughsient@gmail.com, alex.bazhaniuk@eclypsium.com,
        alison.schofield@intel.com, keescook@chromium.org
References: <20220203164328.203629-1-martin.fernandez@eclypsium.com>
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 <ec9e29a4-0d2b-1423-d92e-6f025b56f8cc@amd.com> <Yf1UO6jF91o9k4jB@zn.tnic>
From:   Tom Lendacky <thomas.lendacky@amd.com>
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On 2/4/22 10:28, Borislav Petkov wrote:
> On Fri, Feb 04, 2022 at 10:23:22AM -0600, Limonciello, Mario wrote:
>>>>> As there is interest in seeing these capabilities from userspace, it
> 
> This needs to be explained in a lot more detail: why, what is going to
> use it, how, etc.
> 
> We don't do user-visible APIs just because.
> 
>> As Tom agreed in previous post, Boris is mistaken here.  I just double
>> checked on my side on a workstation that supports SME and comparing
>> /proc/cpuinfo before and after SME is enabled via mem_encrypt=on.  I
>> confirmed that nothing changed.
> 
> Then we should clear that "sme" flag if memory encryption is not
> enabled. Like we do for all other flags.

If we do that, then this will have to be re-worked:

https://elixir.bootlin.com/linux/latest/source/arch/x86/kernel/process.c#L761

Thanks,
Tom

>