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 1D204C433F5 for ; Wed, 23 Feb 2022 16:20:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242721AbiBWQUg (ORCPT ); Wed, 23 Feb 2022 11:20:36 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56642 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234267AbiBWQUd (ORCPT ); Wed, 23 Feb 2022 11:20:33 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B2A9AC2E57; Wed, 23 Feb 2022 08:20:05 -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 dfw.source.kernel.org (Postfix) with ESMTPS id 3558161991; Wed, 23 Feb 2022 16:20:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 16D36C340E7; Wed, 23 Feb 2022 16:20:04 +0000 (UTC) Authentication-Results: smtp.kernel.org; dkim=pass (1024-bit key) header.d=zx2c4.com header.i=@zx2c4.com header.b="UStiHDap" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=zx2c4.com; s=20210105; t=1645633199; 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=mnNQghKSAwgVNaMKLb/7Trnd/MlpODo5RAJNJEkv+10=; b=UStiHDapBFGqlKj1XnAopIV0s/o4/wZAQt9kfn6UaRkkAF7dlnJ3QqN5tRoz/ZORj1iyB8 vZrQhcosPVD9IGzkANuD0g+v6mzrFASmeIaYq1MLaU1R7pw64al2PYmaHQo/tzRlnilQV3 twyhhu3J7BJ8itNYnKzpSPL2yJlYi2o= Received: by mail.zx2c4.com (ZX2C4 Mail Server) with ESMTPSA id f2b47955 (TLSv1.3:AEAD-AES256-GCM-SHA384:256:NO); Wed, 23 Feb 2022 16:19:59 +0000 (UTC) Received: by mail-yw1-f170.google.com with SMTP id 00721157ae682-2d07c4a0d06so216796747b3.13; Wed, 23 Feb 2022 08:19:58 -0800 (PST) X-Gm-Message-State: AOAM532sMYVig0AJIED7HaxncuMXSE8p8sWohVSJNx6/ZVLkj0euEdTq m5rVDcd9iq/dXWrkcJ7jgXyexa+1tBy2PSK9AZI= X-Google-Smtp-Source: ABdhPJzwqPvYWBp9LmD+Jha02PrV5WLBK/ki8ek/2uyVWgeaMR+4EcGUKMupw6bI8EUKZpQFGjPwDZfx/kujcdtLLBc= X-Received: by 2002:a81:5c83:0:b0:2d2:c136:70f3 with SMTP id q125-20020a815c83000000b002d2c13670f3mr401327ywb.404.1645633196792; Wed, 23 Feb 2022 08:19:56 -0800 (PST) MIME-Version: 1.0 References: <20220223131231.403386-1-Jason@zx2c4.com> In-Reply-To: From: "Jason A. Donenfeld" Date: Wed, 23 Feb 2022 17:19:45 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH RFC v1 0/2] VM fork detection for RNG To: LKML , Linux Crypto Mailing List , QEMU Developers , KVM list , linux-s390@vger.kernel.org, adrian@parity.io Cc: "Woodhouse, David" , "Catangiu, Adrian Costin" , graf@amazon.com, Colm MacCarthaigh , "Singh, Balbir" , "Weiss, Radu" , Jann Horn , Greg Kroah-Hartman , "Theodore Ts'o" , Igor Mammedov , ehabkost@redhat.com, ben@skyportsystems.com, "Michael S. Tsirkin" , lersek@redhat.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Feb 23, 2022 at 5:08 PM Jason A. Donenfeld wrote: > > On Wed, Feb 23, 2022 at 2:12 PM Jason A. Donenfeld wrote: > > second patch is the reason this is just an RFC: it's a cleanup of the > > ACPI driver from last year, and I don't really have much experience > > writing, testing, debugging, or maintaining these types of drivers. > > Ideally this thread would yield somebody saying, "I see the intent of > > this; I'm happy to take over ownership of this part." That way, I can > > focus on the RNG part, and whoever steps up for the paravirt ACPI part > > can focus on that. > > I actually managed to test this in QEMU, and it seems to work quite well. Steps: > > $ qemu-system-x86_64 ... -device vmgenid,guid=auto -monitor stdio > (qemu) savevm blah > (qemu) quit > $ qemu-system-x86_64 ... -device vmgenid,guid=auto -monitor stdio > (qemu) loadvm blah > > Doing this successfully triggers the function to reinitialize the RNG > with the new GUID. (It appears there's a bug in QEMU which prevents > the GUID from being reinitialized when running `loadvm` without > quitting first; I suppose this should be discussed with QEMU > upstream.) > > So that's very positive. But I would appreciate hearing from some > ACPI/Virt/Amazon people about this. Because something something picture thousand words something, here's a gif to see this working as expected: https://data.zx2c4.com/vmgenid-appears-to-work.gif Jason