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 lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 9AF1DC43334 for ; Fri, 8 Jul 2022 12:03:11 +0000 (UTC) Received: from localhost ([::1]:35982 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1o9mhS-0005G1-CP for qemu-devel@archiver.kernel.org; Fri, 08 Jul 2022 08:03:10 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:42204) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o9mf1-0003GU-9F for qemu-devel@nongnu.org; Fri, 08 Jul 2022 08:00:39 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:47552) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1o9mex-0003AS-Jj for qemu-devel@nongnu.org; Fri, 08 Jul 2022 08:00:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1657281634; h=from:from:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:in-reply-to:in-reply-to: references:references; bh=CetBy821X1I05bkPAQiMsYFOp07QwUOZEbeeyBpzZ0M=; b=K662Hioe1pdtcNIwVab+D+EpFa7WgNBzNc6okzQDSvB1ZQqLKbfEhVcwO+3pFY51kbjD6W AVIiWgI1LH7XdlNfahSsTuXfl2QOQfXeu59kEpQ1y4LDbNbaz2lELUteq6L6vd2yiRQqYl fwnCjbvMVCcgo9z/hb6hg7xGtit5N8I= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-401-g0TZ9qB_MSuK8V9b1fXe8w-1; Fri, 08 Jul 2022 08:00:33 -0400 X-MC-Unique: g0TZ9qB_MSuK8V9b1fXe8w-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 2D8FB1C00140; Fri, 8 Jul 2022 12:00:32 +0000 (UTC) Received: from redhat.com (unknown [10.33.36.58]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6C1FB1400E74; Fri, 8 Jul 2022 12:00:31 +0000 (UTC) Date: Fri, 8 Jul 2022 13:00:29 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: "Jason A. Donenfeld" Cc: qemu-devel@nongnu.org Subject: Re: [PATCH] hw/i386: pass RNG seed to e820 setup table Message-ID: References: <20220630113717.1893529-1-Jason@zx2c4.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20220630113717.1893529-1-Jason@zx2c4.com> User-Agent: Mutt/2.2.6 (2022-06-05) X-Scanned-By: MIMEDefang 2.85 on 10.11.54.7 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -28 X-Spam_score: -2.9 X-Spam_bar: -- X-Spam_report: (-2.9 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.082, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, T_SCC_BODY_TEXT_LINE=-0.01 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Jun 30, 2022 at 01:37:17PM +0200, Jason A. Donenfeld wrote: > Tiny machines optimized for fast boot time generally don't use EFI, > which means a random seed has to be supplied some other way, in this > case by the e820 setup table, which supplies a place for one. This > commit adds passing this random seed via the table. It is confirmed to > be working with the Linux patch in the link. IIUC, this approach will only expose the random seed when QEMU is booted using -kernel + -initrd args. I agree with what you say about most VMs not using UEFI right now. I'd say the majority of general purpose VMs are using SeaBIOS still. The usage of -kernel + -initrd, is typically for more specialized use cases. IOW, exposing random seed via the setup table feels like it'll have a somewhat limited benefit. Can we get an approach that exposes a random seed regardless of whether using -kernel, or seabios, or uefi, or $whatever firmware ? Perhaps (ab)use 'fw_cfg', which is exposed for any x86 VM no matter what config it has for booting ? With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|