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Donenfeld" Cc: "Dr. Greg" , "Daniel P. Berrang??" , "Reshetova, Elena" , "Hansen, Dave" , "Kirill A. Shutemov" , Thomas Gleixner , Ingo Molnar , Dave Hansen , "H. Peter Anvin" , "x86@kernel.org" , Theodore Ts'o , Kuppuswamy Sathyanarayanan , "Nakajima, Jun" , Tom Lendacky , "Kalra, Ashish" , Sean Christopherson , "linux-coco@lists.linux.dev" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH 2/2] x86/random: Issue a warning if RDRAND or RDSEED fails Message-ID: <20240209214530.GHZcac-vOym8k3IuJm@fat_crate.local> References: <20240206011247.GA29224@wind.enjellic.com> <20240206120445.GA1247@wind.enjellic.com> <20240206153529.GHZcJRwTdDkWXuopOQ@fat_crate.local> <20240208114444.GA23164@wind.enjellic.com> <20240209173102.GBZcZhVuFJZ8JOKTjG@fat_crate.local> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Fri, Feb 09, 2024 at 08:49:40PM +0100, Jason A. Donenfeld wrote: > While you're here, I was here the whole time, lurking in the shadows. :) > Is it actually possible to make RDRAND usage "fair" between different > security contexts? Or am I totally delusional and this is not how the > hardware works or can ever work? Yeah, I know exactly what you mean and I won't go into details for obvious reasons. Two things: * Starting with Zen3, provided properly configured hw RDRAND will never fail. It is also fair when feeding the different contexts. * My hardware engineers tell me that this is tough to do for RDSEED Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette