linux-kernel - Re: [PATCH v2 1/1] x86/rdrand: disable RDSEED on AMD Cyan Skillfish

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Message-ID: <20260114212837.GHaWgKhZUMYKfrIclM@fat_crate.local>
Date: Wed, 14 Jan 2026 22:28:37 +0100
From: Borislav Petkov <bp@...en8.de>
To: Travis B <tbangs89@...il.com>
Cc: me@...aill.net, dave.hansen@...ux.intel.com,
	linux-kernel@...r.kernel.org, mario.limonciello@....com,
	mingo@...hat.com, tglx@...utronix.de, x86@...nel.org
Subject: Re: [PATCH v2 1/1] x86/rdrand: disable RDSEED on AMD Cyan Skillfish

On Wed, Jan 14, 2026 at 03:52:16PM -0500, Travis B wrote:
> These should be pr_notice_once instead.

The _once aspect does make sense - we're issuing this for each CPU.

> (the message is also shown dozens of times in a row currently)

It is still important, though, to make sure the user sees this and does not
use RDSEED for generating random data used in sensitive communication. So
issuing it at least once but making sure everything sees it.

> Currently users of BC-250 have no way of disabling the RDSEED

And they wanna disable it because?

-- 
Regards/Gruss,
    Boris.

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