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 9E240C433F5 for ; Fri, 25 Feb 2022 15:28:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242077AbiBYP3O (ORCPT ); Fri, 25 Feb 2022 10:29:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57544 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231340AbiBYP3M (ORCPT ); Fri, 25 Feb 2022 10:29:12 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 87E4D51E44; Fri, 25 Feb 2022 07:28:39 -0800 (PST) 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 33D27B83250; Fri, 25 Feb 2022 15:28:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 77BC2C340F0; Fri, 25 Feb 2022 15:28:34 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="WRm6cOGF" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1645802913; h=from:from: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=AGc3HtA6A4VpWTuoF56TukEqyXDHbzPy+Zb56qBmVE4=; b=WRm6cOGFOImn/aW/r2uMGAAnP99kIhA6KQkGrSddTUVxAkWVY9oezzK7F6YN6oeSPEX00v XVn/gXm/ZD0Khupal1wI4/zPDplhrs4umww7//LN2a9PB1DjWjGzF4rwRukBQLnbj5EMHE FRzEd8Ep4ZckCmimiThiqkYgmQENeqQ= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id 8a164ef4 (TLSv1.3:AEAD-AES256-GCM-SHA384:256:NO); Fri, 25 Feb 2022 15:28:32 +0000 (UTC) Date: Fri, 25 Feb 2022 16:28:29 +0100 From: "Jason A. Donenfeld" To: Alexander Graf Cc: kvm@vger.kernel.org, linux-crypto@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, adrian@parity.io, ardb@kernel.org, ben@skyportsystems.com, berrange@redhat.com, colmmacc@amazon.com, decui@microsoft.com, dwmw@amazon.co.uk, ebiggers@kernel.org, ehabkost@redhat.com, gregkh@linuxfoundation.org, haiyangz@microsoft.com, imammedo@redhat.com, jannh@google.com, kys@microsoft.com, lersek@redhat.com, linux@dominikbrodowski.net, mst@redhat.com, qemu-devel@nongnu.org, raduweis@amazon.com, sthemmin@microsoft.com, tytso@mit.edu, wei.liu@kernel.org Subject: Re: [PATCH v4] virt: vmgenid: introduce driver for reinitializing RNG on VM fork Message-ID: References: <20220225124848.909093-1-Jason@zx2c4.com> <05c9f2a9-accb-e0de-aac7-b212adac7eb2@amazon.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org Hi Alex, On Fri, Feb 25, 2022 at 04:15:59PM +0100, Alexander Graf wrote: > I'm not talking about a notification interface - we've gone through > great length on that one in the previous submission. What I'm more > interested in is *any* way for user space to read the current VM Gen ID. > The same way I'm interested to see other device attributes of my system > through sysfs. Again, no. Same basic objection: we can do this later and design it coherently with the rest. For example, maybe it's better to expose a generation counter rather than 16 byte blob, and expect userspace to call getrandom() subsequently to get something fresh. Or not! But maybe it should be hashed with a fixed prefix string before being exposed to userspace. Or not! I don't know, but that's not going to happen on this patchset. There is no reason at all why that needs to be done here and now. Trying to do too much at the same time is likely why the previous efforts from your team stalled out last year. Propose something later, in a new thread, and we can discuss then. One step at a time... Jason