linux-kernel - Re: [PATCH v2] x86/amd: Disable RDSEED on AMD Zen5 because of an error.

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Message-ID: <aPT9vUT7Hcrkh6_l@zx2c4.com>
Date: Sun, 19 Oct 2025 17:03:25 +0200
From: "Jason A. Donenfeld" <Jason@...c4.com>
To: Borislav Petkov <bp@...en8.de>
Cc: Gregory Price <gourry@...rry.net>, x86@...nel.org,
	linux-kernel@...r.kernel.org, tglx@...utronix.de, mingo@...hat.com,
	dave.hansen@...ux.intel.com, hpa@...or.com, peterz@...radead.org,
	mario.limonciello@....com, riel@...riel.com, yazen.ghannam@....com,
	me@...aill.net, kai.huang@...el.com, sandipan.das@....com,
	darwi@...utronix.de, stable@...r.kernel.org
Subject: Re: [PATCH v2] x86/amd: Disable RDSEED on AMD Zen5 because of an
 error.

On Sun, Oct 19, 2025 at 05:00:27PM +0200, Borislav Petkov wrote:
> On Sun, Oct 19, 2025 at 04:46:06PM +0200, Jason A. Donenfeld wrote:
> > While your team is checking into this, I'd be most interested to know
> > one way or the other whether this affects RDRAND too.
> 
> No it doesn't, AFAIK. The only one affected is the 32-bit or 16-bit dest
> operand version of RDSEED. Again, AFAIK.

Oh good. So on 64-bit kernels, the impact to random.c is zilch.

Jason