From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.mixaill.net (mail.mixaill.net [144.76.234.135]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BD646146D57 for ; Fri, 14 Mar 2025 08:16:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=144.76.234.135 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741940213; cv=none; b=b9s5LqnKg4W8BHlvxa+kk0X28sFf200aRJ6lkTSPhjMCqQX2pCTs3+tUIW0WA+2PhPHnMyUmh/rV2iblV/DQBOHXQnYkINdCFxu7PEgkI53Cf92qEGyGVrbZAFGXDBcx9qVtTwKS9MPW60c5O8IUKlsN/Wessm08syzEkx64eWw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741940213; c=relaxed/simple; bh=qtEM2RgClCdglNPiuqQUBYADihyceogRF/upsA6Xjbo=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Qm1cP/ufwMC0SvM/vR1ogb+bhcuP+C1NUBCOH7GpNG4XzlzQ6Feaj6DGP+0pNwiha+F28NnKnIOc9zK4bzNEOn69yRkN0uPZmJGmcCrZWc+iwcSyH3RSBDBlKM8Siji3w6ORr+UrEkwit9amu46sO+Ie/hYmcG/D9vf301r74ZA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mixaill.net; spf=pass smtp.mailfrom=mixaill.net; dkim=pass (2048-bit key) header.d=mixaill.net header.i=@mixaill.net header.b=pOtrRZ6I; arc=none smtp.client-ip=144.76.234.135 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=mixaill.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mixaill.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=mixaill.net header.i=@mixaill.net header.b="pOtrRZ6I" Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 4F99C6C954; Fri, 14 Mar 2025 08:16:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mixaill.net; s=dkim; t=1741940203; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:content-language:in-reply-to:references; bh=w1uvea5ckxLu4teNZEVtDlewztPYEl58uFFERrRbb1o=; b=pOtrRZ6I3cJS5Rcp3pA9D4p5K/8Ql3L0SZUifeOzaAcOay7MwSbXMLLVoSXaSBQ+Gd/kar 6SzCBjX/Sx2vo5S9cnW15tC9kPf2uVXDsVCmgrzpP4q1BCDF6JoStTJAdgfvtdAToC8a8J r2HxxT//q7ow5EHLccD5RfWcIbDwEbnVgSVH7q4b6hU1TaA+ZhnKALgFMWMHOi5RreWLL/ p/DKeVGSMFGMXE8LLXMoPhkaztleJbBoSKNzh78uzeGqnJRh/ERE7LNrEBPzLghw13/oGN iOkWQrhQveKcegZtinZoAUEGcWLArk//rnA110bcARmF0vaOze1N+/J95xQgtA== Message-ID: <4aa902e5-24f8-4ae6-bc6b-485b7578fb27@mixaill.net> Date: Fri, 14 Mar 2025 11:16:41 +0300 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 0/2] x86/rdrand: implement sanity check for RDSEED To: Borislav Petkov Cc: Thomas Gleixner , Ingo Molnar , Dave Hansen , x86@kernel.org, linux-kernel@vger.kernel.org References: <20250312123130.8290-1-me@mixaill.net> <20250313173205.GIZ9MWlT9ElklGPSrD@fat_crate.local> Content-Language: en-US From: Mikhail Paulyshka In-Reply-To: <20250313173205.GIZ9MWlT9ElklGPSrD@fat_crate.local> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Last-TLS-Session-Version: TLSv1.3 On 3/13/25 8:32 PM, Borislav Petkov wrote: > On Wed, Mar 12, 2025 at 03:31:28PM +0300, Mikhail Paulyshka wrote: >> On the AMD Cyan Skillfish (Family 0x17 Model 0x47 Stepping 0x0), which >> is a Zen2-based APU found on the AMD BC-250 board, there is a situation >> where RDRAND works fine, but RDSEED generates FF. > On every read? Or only sometimes? I didn't find a situation where it returns something different, so yes, I believe it happens on every read and tested on 3+ hardware samples. > Is CF clear when it returns FF? Just right after rdseed %edx # info registers edx edx 0xffffffff -1 # info registers eflags eflags 0x203 [ CF IF ]