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Date: Tue, 30 Jan 2024 10:15:35 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
To: Dave Hansen <dave.hansen@intel.com>,
        "Jason A. Donenfeld" <Jason@zx2c4.com>
CC: "Reshetova, Elena" <elena.reshetova@intel.com>,
        "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
        Thomas Gleixner <tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>,
        Borislav Petkov <bp@alien8.de>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "x86@kernel.org" <x86@kernel.org>, "Theodore Ts'o" <tytso@mit.edu>,
        Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>,
        "Nakajima, Jun" <jun.nakajima@intel.com>,
        Tom Lendacky <thomas.lendacky@amd.com>,
        "Kalra, Ashish" <ashish.kalra@amd.com>,
        Sean Christopherson <seanjc@google.com>,
        "linux-coco@lists.linux.dev" <linux-coco@lists.linux.dev>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/2] x86/random: Issue a warning if RDRAND or RDSEED fails
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On January 30, 2024 9:58:09 AM PST, Dave Hansen <dave=2Ehansen@intel=2Ecom>=
 wrote:
>On 1/30/24 09:49, Jason A=2E Donenfeld wrote:
>>> Anybody disagree?
>> Yes, I disagree=2E I made a trivial test that shows RDSEED breaks easil=
y
>> in a busy loop=2E So at the very least, your statement holds true only
>> for RDRAND=2E
>
>Well, darn=2E :)
>
>Any chance you could share some more information about the environment
>where you're seeing this?  It'd be good to reconcile what you're seeing
>with how the hardware is expected to behave=2E

What CPU is this and could you clarify exactly how you run your busy loop?