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From: Thiago Macieira <thiago.macieira@intel.com>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Borislav Petkov <bp@alien8.de>,
	Christopher Snowhill <chris@kode54.net>,
	Gregory Price <gourry@gourry.net>,
	x86@kernel.org, linux-kernel@vger.kernel.org, tglx@linutronix.de,
	mingo@redhat.com, dave.hansen@linux.intel.com, hpa@zytor.com,
	peterz@infradead.org, mario.limonciello@amd.com,
	riel@surriel.com, yazen.ghannam@amd.com, me@mixaill.net,
	kai.huang@intel.com, sandipan.das@amd.com, darwi@linutronix.de,
	stable@vger.kernel.org
Subject: Re: [PATCH v2] x86/amd: Disable RDSEED on AMD Zen5 because of an error.
Date: Fri, 07 Nov 2025 11:55:35 -0800	[thread overview]
Message-ID: <2790505.9o76ZdvQCi@tjmaciei-mobl5> (raw)
In-Reply-To: <aQ5E2ArhkmziwWA8@zx2c4.com>

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On Friday, 7 November 2025 11:13:28 Pacific Standard Time Jason A. Donenfeld 
wrote:
> > But consider people who haven't upgraded Linux (yes, we get people asking
> > to keep everything intact in their system, but upgrade Qt only, then
> > complain when our dependency minimums change). How much of an impact
> > would they have?
> I suppose you could benchmark it and see if it matters. The syscall is
> obviously slower than the megafast vDSO code, so it will probably also
> be a bit slower than the MT code. But I suspect for most use cases maybe
> it doesn't matter that much? It's worth a try and seeing if anybody
> complains.

I'm not asking about the performance of generating new random numbers in this 
process.

I am asking about the system-wide impact that draining the entropy source 
would have. Is that a bad thing?

I suspect the answer is "no" because it's the same as /dev/urandom anyway.

-- 
Thiago Macieira - thiago.macieira (AT) intel.com
  Principal Engineer - Intel DCG - Platform & Sys. Eng.

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  reply	other threads:[~2025-11-07 19:55 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-10-18  2:40 Gregory Price
2025-10-18 10:03 ` Borislav Petkov
2025-10-19 14:46   ` Jason A. Donenfeld
2025-10-19 15:00     ` Borislav Petkov
2025-10-19 15:03       ` Jason A. Donenfeld
2025-11-03 10:22         ` Christopher Snowhill
2025-11-03 12:03           ` Borislav Petkov
2025-11-03 23:55             ` Christopher Snowhill
2025-11-04 13:21               ` Borislav Petkov
2025-11-04 14:28                 ` Jason A. Donenfeld
2025-11-04 15:00                   ` Jason A. Donenfeld
2025-11-04 18:08                   ` Thiago Macieira
2025-11-04 21:56                     ` Jason A. Donenfeld
2025-11-04 23:50                       ` Thiago Macieira
2025-11-05  1:58                         ` Jason A. Donenfeld
2025-11-05 16:41                           ` Thiago Macieira
2025-11-07 19:13                             ` Jason A. Donenfeld
2025-11-07 19:55                               ` Thiago Macieira [this message]
2025-11-07 23:07                                 ` Jason A. Donenfeld
2025-11-07 23:11                                   ` Thiago Macieira
2025-11-08  0:04                                     ` Jason A. Donenfeld

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