linux-kernel - Re: [PATCH] x86/sev: Make SEV

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Message-ID: <20250305115035.GEZ8g6i7NTiSfkxk7J@fat_crate.local>
Date: Wed, 5 Mar 2025 12:50:35 +0100
From: Borislav Petkov <bp@...en8.de>
To: Ingo Molnar <mingo@...nel.org>
Cc: Joerg Roedel <joro@...tes.org>, x86@...nel.org, hpa@...or.com,
	Tom Lendacky <thomas.lendacky@....com>,
	Nikunj A Dadhania <nikunj@....com>, linux-kernel@...r.kernel.org,
	Larry.Dewey@....com, Joerg Roedel <jroedel@...e.de>
Subject: Re: [PATCH] x86/sev: Make SEV_STATUS available via SYSFS

On Wed, Mar 05, 2025 at 12:42:41PM +0100, Ingo Molnar wrote:
> So if the convenience of tooling is the argument, the raw feature mask 
> exposed is the best option overall.

The convenience of tooling *and* user. I want both. I want to be able to boot
a guest and see what features are enabled without needing a tool.

And, at the same time, tools should be able to use the same interface.

Exactly like we *and glibc* use /proc/cpuinfo today. Now think the same thing
but for confidential guests.

> So the /sys/devices/system/cpu/sev/ directory already exists and your 
> arguments already apply to that, don't they?

Lemme repeat:

>> - a .../sev sysfs file clearly doesn't cut it because TDX doesn't have "sev"
>>   - it is the Intel version of a confidential guest

>> - we have a general need to expose what a confidential guest supports

> As to the hex numbers - do you prefer to put string versions of these 
> into the sysfs file:

See above.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette