From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 20FB53A1AC; Sat, 31 Aug 2024 08:14:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725092064; cv=none; b=gmicBdTh9z35mumi5A4RkiAVl4D1RTOZqqzjkeitcMHy3x8OSd5RuM3ZNPfhpjz2WUyFc/982p4bI0fT1WyiKI0xredAcmEc85fue2bi+TXZ7EvTgppW6fqeE1/alMzcnfEnSKsWrh64APHBj3dnP4En4VdBGbtSl5d149az308= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1725092064; c=relaxed/simple; bh=dC9woE6OiFq0DFYL5jgTE8HMEHaGEFxF7EU9YoSWi08=; h=Date:Message-ID:From:To:Cc:Subject:In-Reply-To:References: MIME-Version:Content-Type; b=HOhXH3X+ZrYO5rUK1DM+3Pjl0HEb/78p3NgWA8t+6MSS/E4AYXzKy92rhsxRY/Id7qCFuKuSlxqz6n6cWBtzHISKc/wAG/5kCa3nBdsk+TXFsUyjYVDEQpzEB6OxtBz0wMxclrSr83LW6VORcCXDoKb0Bi3yWQdCUa9z8f1Bbyc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Gz4m3+VO; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Gz4m3+VO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AEFA7C4CEC0; Sat, 31 Aug 2024 08:14:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1725092063; bh=dC9woE6OiFq0DFYL5jgTE8HMEHaGEFxF7EU9YoSWi08=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Gz4m3+VOTfGPQsRcJ+UVGQ+eae0g6/yUULBTyB65x7lfUuD0KLipbA4oTKNlSzo6F r7odGqqocNQvce2SYMYH6wWiZSbEQ9R96Z+jT03qX6P2eI/MDv8CY7eX13kRmOP2lh zAPhjfXvj3IUzc+DIHnyDFiC0T6+KHP1st2su9fJ6gfSJCuRrgA267lEC8p70a5TTB g5hYsmMW1lbBzUlUUAcy1B7dJS5xM+i32dsutdFFKDVI6H6tzwpQT5vOa0OUYSgBWW r05ASkp1FwhEKzAzSn4zRSPisH7GzcyBtf4S+vix0l1lt2Xh1F3bCLOvThO8STw852 eSwscLlvFNuRg== Received: from sofa.misterjones.org ([185.219.108.64] helo=goblin-girl.misterjones.org) by disco-boy.misterjones.org with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.95) (envelope-from ) id 1skJFV-008Rjk-Eh; Sat, 31 Aug 2024 09:14:21 +0100 Date: Sat, 31 Aug 2024 09:14:20 +0100 Message-ID: <86y14dun1f.wl-maz@kernel.org> From: Marc Zyngier To: Ard Biesheuvel Cc: Tangnianyao , Will Deacon , oliver.upton@linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, "guoyang (C)" Subject: Re: Question on get random long worse in VM than on host In-Reply-To: References: <214e37e9-7aba-1e61-f63f-85cb10c9a878@huawei.com> <86zfotuoio.wl-maz@kernel.org> User-Agent: Wanderlust/2.15.9 (Almost Unreal) SEMI-EPG/1.14.7 (Harue) FLIM-LB/1.14.9 (=?UTF-8?B?R29qxY0=?=) APEL-LB/10.8 EasyPG/1.0.0 Emacs/29.4 (aarch64-unknown-linux-gnu) MULE/6.0 (HANACHIRUSATO) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII X-SA-Exim-Connect-IP: 185.219.108.64 X-SA-Exim-Rcpt-To: ardb@kernel.org, tangnianyao@huawei.com, will@kernel.org, oliver.upton@linux.dev, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, kvmarm@lists.linux.dev, guoyang2@huawei.com X-SA-Exim-Mail-From: maz@kernel.org X-SA-Exim-Scanned: No (on disco-boy.misterjones.org); SAEximRunCond expanded to false On Sat, 31 Aug 2024 08:56:23 +0100, Ard Biesheuvel wrote: > > As for RNDR/RNDRRS vs TRNG: the former is not a raw entropy source, it > is a DRBG (or CSPRNG) which provides cryptographically secure random > numbers whose security strength is limited by the size of the seed. > TRNG does not have this limitation in principle, although non-p KVM > happily seeds it from the kernel's entropy pool, which has the same > limitation in practice. Is that something we should address? I assume that this has an impact on the quality of the provided random numbers? Thanks, M. -- Without deviation from the norm, progress is not possible.