From: "Jason A. Donenfeld" <Jason@zx2c4.com>
To: Thiago Macieira <thiago.macieira@intel.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, 7 Nov 2025 20:13:28 +0100 [thread overview]
Message-ID: <aQ5E2ArhkmziwWA8@zx2c4.com> (raw)
In-Reply-To: <1903914.sHLxoZxqIA@tjmaciei-mobl5>
On Wed, Nov 05, 2025 at 08:41:01AM -0800, Thiago Macieira wrote:
> > Oh yea, good question. Well, with every major OS now having a mechanism
> > to skip syscalls for random numbers, I guess you could indeed just alias
> > global() to system() and call it a day. Then users really cannot shoot
> > themselves in the foot. That would be simpler too. Seems like the best
> > option.
>
> Indeed.
>
> 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.
Jason
next prev parent reply other threads:[~2025-11-07 19:13 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-18 2:40 [PATCH v2] x86/amd: Disable RDSEED on AMD Zen5 because of an error 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 [this message]
2025-11-07 19:55 ` Thiago Macieira
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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