From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 61296C433EF for ; Mon, 25 Apr 2022 12:10:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235048AbiDYMNC (ORCPT ); Mon, 25 Apr 2022 08:13:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50502 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234940AbiDYMMu (ORCPT ); Mon, 25 Apr 2022 08:12:50 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B00075B3C2; Mon, 25 Apr 2022 05:09:46 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 5CFC1B8160E; Mon, 25 Apr 2022 12:09:45 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4FC5AC385A7; Mon, 25 Apr 2022 12:09:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1650888584; bh=1cGqa9zyT58RE2mP9Te3PxJ0mlr36OZJHKDXdnMZfr0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lF9f5yW897I0R3eQH311XOACxuKiPKWTs8ZKJ4KDbI/UkGn3qWUHChSAaAE/4Og3U yBZ2nTQ1Ykj224QMHk5YVtaftIlMrNgme88N4KotkNcY9mW7Vmrx3n4WbU8yh6PoES nF1PyLMFvhqA3xI2Jm6GnK4UPiPFawD6ggvWmRwZkfd0/w2P7FSP0gZrC13cFx1CJX 50uCeKszDyL5YGy+dlzB7+V4d7DjEELMB9Vq1jCpO7MFTl05NRXat79UdxwfDw2R1F 2uGHTHMY8nn1VDwRSdu7Kxb9F87cv7Jpoborq4dXI91GWbJaDn1sLC5+YYlrpqrT1l aeyR5bEwsmmRw== Date: Mon, 25 Apr 2022 13:09:34 +0100 From: Mark Brown To: "Jason A. Donenfeld" Cc: Arnd Bergmann , Guenter Roeck , Linux Kernel Mailing List , "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" , linux-arch , Dinh Nguyen , Nick Hu , Max Filippov , Palmer Dabbelt , "David S . Miller" , Yoshinori Sato , Michal Simek , Borislav Petkov , Guo Ren , Geert Uytterhoeven , Joshua Kinard , David Laight , Dominik Brodowski , Eric Biggers , Ard Biesheuvel , Thomas Gleixner , Andy Lutomirski , Kees Cook , Lennart Poettering , Konstantin Ryabitsev , Linus Torvalds , Greg Kroah-Hartman , Theodore Ts'o Subject: Re: [PATCH v1] random: block in /dev/urandom Message-ID: References: <20220217162848.303601-1-Jason@zx2c4.com> <20220322155820.GA1745955@roeck-us.net> <0d20fb04-81b8-eeee-49ab-5b0a9e78c9f8@roeck-us.net> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="onvU6J0IiWNDQHVw" Content-Disposition: inline In-Reply-To: X-Cookie: An apple a day makes 365 apples a year. Precedence: bulk List-ID: X-Mailing-List: linux-crypto@vger.kernel.org --onvU6J0IiWNDQHVw Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Sat, Apr 23, 2022 at 02:52:51AM +0200, Jason A. Donenfeld wrote: > On Wed, Mar 23, 2022 at 4:53 PM Arnd Bergmann wrote: > > Maybe kernelci has a virtio-rng device assigned to the machine > > and you don't? That would clearly avoid the issue here. > Indeed it's probably something like that. Or maybe they're networked > with something that has a steady stream of interrupts. I say this > because I was able to reproduce Guenter's findings using the > versatilepb machine with the versatile_defconfig config and the > versatile-pb.dtb file. Indeed this board doesn't have a cycle counter. > However, I did have success using the fallback timer and the other > patches in the jd/for-guenter branch, so at least for versatile's > nuances, I think (hope?) there's a reasonable success story here. There's no virtio-rng device being instantiated, unless qemu is doing that by default (I can't see anything in the logs that suggests it did). There is networking though. A sample command for invoking qemu for versatilepb is: qemu-system-arm -cpu arm926 -machine versatilepb -nographic -net nic,model=smc91c111,macaddr=52:54:00:12:34:58 -net user -m 256 -monitor none -dtb /var/lib/lava/dispatcher/tmp/85180/deployimages-hitd6sn_/dtb/versatile-pb.dtb -kernel /var/lib/lava/dispatcher/tmp/85180/deployimages-hitd6sn_/kernel/zImage -append "console=ttyAMA0,115200 root=/dev/ram0 debug verbose console_msg_format=syslog earlycon" -initrd /var/lib/lava/dispatcher/tmp/85180/deployimages-hitd6sn_/ramdisk/rootfs.cpio.gz -drive format=qcow2,file=/var/lib/lava/dispatcher/tmp/85180/apply-overlay-guest-l9_f_lxl/lava-guest.qcow2,media=disk,if=scsi,id=lavatest --onvU6J0IiWNDQHVw Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmJmj34ACgkQJNaLcl1U h9CeWwf/Yaj9E+Pc63nMbfJFj83Dzh5N/lIq7zixSu3FpWYBuYqbtE8Dmnnch2Rg WWWZuPFHNUsUnTfVjCf6UUhoVa0gVphiNVhGZ3AR18HCxB6jpmue2o0rjuGvhpw0 G8gmLrP1qTXptqiG3bG2SNmAzazeqxsl+KRseLjhSRKzDzQbDFByTNePc6pmKDJW gAqV2YZfGNSNOz2nvzqwTXVK4vL7/QPB2sVEVlkb9uSuOWbNSMrcCtNsfeWzY4hQ h45dDgk/+DigcTOCpBNOq4+bMGHy+wXKzMsT37S3t4YFd0gimba4r/CbVsYWmo/6 z9ktO6xoFAC+q42db0+s6en2SzVLLg== =/kLK -----END PGP SIGNATURE----- --onvU6J0IiWNDQHVw--