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 lists1p.gnu.org (lists1p.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 EC519CD4F54 for ; Wed, 27 May 2026 08:51:46 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists1p.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1wS9yx-0007PE-OC; Wed, 27 May 2026 04:51:19 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists1p.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wS9yq-0007Om-2S for qemu-devel@nongnu.org; Wed, 27 May 2026 04:51:13 -0400 Received: from flow-a2-smtp.messagingengine.com ([103.168.172.137]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1wS9yn-0000ba-U4 for qemu-devel@nongnu.org; Wed, 27 May 2026 04:51:11 -0400 Received: from phl-compute-05.internal (phl-compute-05.internal [10.202.2.45]) by mailflow.phl.internal (Postfix) with ESMTP id 5999913802E6; Wed, 27 May 2026 04:38:51 -0400 (EDT) Received: from phl-frontend-04 ([10.202.2.163]) by phl-compute-05.internal (MEProxy); Wed, 27 May 2026 04:38:51 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alyssa.is; h=cc :cc:content-type:content-type:date:date:from:from:in-reply-to :in-reply-to:message-id:mime-version:references:reply-to:subject :subject:to:to; s=fm2; t=1779871131; x=1779878331; bh=ZtNZmtiIIS +/5uqlnIxpDzlIEiTdqZ1oGuuwWO812Rk=; b=DLFepVlVEUU3mTXOYqKl4t2kKG Gzyh4GNheQPYIYcov8y7HmD8cT/rfGzx8J5T3qXjJ+S0PXtojhC/QcfwrhXCvNlk PxOBw8GHUcghGz/8IFxUYOpXkvEoKKMObOM/Z9cf7V0jiOUAdYZosKUyG9exzI0V mtX8cdloP92OZyvOQKPFxeEY3iUlBw4dblrC5kkePW1fD9MlQZ94oGDUJjcM/+TK 61e68hTdKWt66rXawGt77Y4ODLjiICirBTIm6PcOnoxm3YNb5XQHeuWXOr6SwvBl 75AZsRqcPAw526y+TcQew9YBrdXe99BICPsYWoQcjwdvhoOsSiIIwHg9RmcA== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:cc:content-type:content-type:date:date :feedback-id:feedback-id:from:from:in-reply-to:in-reply-to :message-id:mime-version:references:reply-to:subject:subject:to :to:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s=fm3; t= 1779871131; x=1779878331; bh=ZtNZmtiIIS+/5uqlnIxpDzlIEiTdqZ1oGuu wWO812Rk=; b=ktocf3k3wPd1cP2DFPw7SyoA4xABdJq3v5rDRstugcynWH+42Ui AllWe9cdCDVZU8Wy0606rfUKTtdvR38ZkeyqvJxnhlytAPuKkMco6oin+zYOYBb2 xgGqRFzuGGwBHwvlmhRchqMuucqdPi6PAzqrjQ5E7f4RIKnD6wqkvei1DZavigaO 5+EJ0vIj/AibYYgXo9d2PsjpQeElATddHdb5mv5qJ924rYz+EJu1jTB4BpvNpL7y XGECWnx2EjyjNfg26Ud2wUEvyJzlbokAcjBkNvBqxi7UtI8CTd6OUE/gVYlxJF4r eyAKwDb0nvBm5ciCqhpOBTZVwp+AONPXgDA== X-ME-Sender: X-ME-Received: X-ME-Proxy-Cause: dmFkZTGAC8yCyMBMPFep+txMvQfFEKOjea1ZMmQG3rz4yqKsMRKTshV8R29jcoIG+ngcD7 AsWN9B4qYRlZDues5y2lR/P20wyJKoYvAO+r/KIWC5W5u/5rYUbrRzc6yuPmSLJI6/FqWn VkOsKBhM+XFy5hu77LiX4dTq4tfcmaBkX5XIhEL7qfb/Gsp8wumodT0trqM/V/InqjhUpy mFBRiWVvoKVtB9t0dLEqLOYbF4/Z+1UquPfguqusSOzvR8/bfird+srmoevnlFmE/T2n/q sF4IkyoRPummlNNApa9neloOdt9HpARJ/z6/e7UGtyWyL2XtPeT9TnrIPHpRUyCubG2CGN 5yQPXAcQUPlgv2TUcYDjBu3Gk1BZYkFolUjMietVWwDYfasRZuryHh1IgMnNXLM+oWdkXy o/Me0aO0LBgWC5g4WjtiHmsDvhuSOR7gPKUF1sRf7eNXhEiBRMdD1F9d3M1vrD+mE+Vodu 7xjdIYgRQM03JQ8bCD3eYXmX3ijTzaHYABs5dqvggyjQSzMQO5OTiwUZBaJ58CBAviJ1RZ hPuTVlyf7JEn4A4QohjgryOIMok/W/4Bo3ZkdzUOZZZRD78pvXs5VQ7b9byc5+h945FwIn 913X51IaFRye6Bx2FvGHdw1+pa6k4jXZ6go+SS521WlxeWA4roxpwe9RiH4Q X-ME-Proxy: Feedback-ID: i12284293:Fastmail Received: by mail.messagingengine.com (Postfix) with ESMTPA; Wed, 27 May 2026 04:38:50 -0400 (EDT) Received: by mbp.qyliss.net (Postfix, from userid 1000) id 419FC8198F13; Wed, 27 May 2026 10:20:16 +0200 (CEST) From: Alyssa Ross To: Alex =?utf-8?Q?Benn=C3=A9e?= , Manos Pitsidianakis Cc: Demi Marie Obenour , Albert Esteve , Markus Armbruster , "Daniel P. Berrange" , =?utf-8?Q?C=C3=A9dric?= Le Goater , Eric Blake , "Edgar E. Iglesias" , Eduardo Habkost , Elena Ufimtseva , Auger Eric , felipe@nutanix.com, Jan Kiszka , Joao Martins , =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , Paolo Bonzini , Peter Maydell , Phil =?utf-8?Q?Mathieu-Daud=C3=A9?= , QEMU Developers , Richard Henderson , Bernhard Beschow , Stefan Hajnoczi , Thomas Huth , Wei Wang Subject: vhost-user(?) breaking changes In-Reply-To: <878q961nkz.fsf@draig.linaro.org> References: <875x4fmzcv.fsf@draig.linaro.org> <96181e0d-4c75-430a-9b80-9d8d0eabcce7@gmail.com> <878q961nkz.fsf@draig.linaro.org> Date: Wed, 27 May 2026 10:20:09 +0200 Message-ID: <87mrxlgt6u.fsf@alyssa.is> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha512; protocol="application/pgp-signature" Received-SPF: pass client-ip=103.168.172.137; envelope-from=hi@alyssa.is; helo=flow-a2-smtp.messagingengine.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, 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_PASS=-0.001, SPF_PASS=-0.001 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: qemu development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org --=-=-= Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable [Trimming CC substantially.] Alex Benn=C3=A9e writes: > Manos Pitsidianakis writes: > >> On Mon, May 25, 2026 at 5:03=E2=80=AFAM Demi Marie Obenour >> wrote: >>> >>> The first is whether vhost-user memory regions >>> are guaranteed to not overlap. I sent a patch in >>> https://lore.kernel.org/qemu-devel/20260522-vhost-user-dev-v1-1-b31646c= f19b8@gmail.com >>> to guarantee this is not the case. However, this is technically a >>> breaking spec change. The virtio vhost-user device I'm working on >>> requires this. > > Breaking spec changes are always a red flag because of whats already > deployed. Are you sure there is no way to make changes optional with use > of feature flags? There's some nuance between breaking changes and clarifications though, right? e.g. 97f24a0496 ("vhost-user.rst: clarify when FDs can be sent") tightened things up, so could also have been in principle have been seen as a breaking change, but not practically. Are there likely to be devices that use overlapping memory regions today? Would we expect that to work? --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEARYKAB0WIQRV/neXydHjZma5XLJbRZGEIw/wogUCahapOQAKCRBbRZGEIw/w om1VAQDMZQB4dyZ5RIn9gjXaSvs5LU8v5JG4AhLkvighhzm09wD9HlNL7heSkkp1 QwckcP0XI70EoJ2VXJhhRwJdGMV5TgA= =YR7B -----END PGP SIGNATURE----- --=-=-=--