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 69C93E9A74B for ; Tue, 24 Mar 2026 09:51:01 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1w4yPF-0001Lk-Oe; Tue, 24 Mar 2026 05:50:39 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1w4yMU-0000pG-0h for qemu-devel@nongnu.org; Tue, 24 Mar 2026 05:47:48 -0400 Received: from mail180-47.suw31.mandrillapp.com ([198.2.180.47]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1w4yMR-000832-G4 for qemu-devel@nongnu.org; Tue, 24 Mar 2026 05:47:45 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mandrillapp.com; s=mte1; t=1774344481; x=1774614481; bh=xySpiGsL6jhSgBQryanlxjULqiUOOXBfzlvPnW3Iw4Y=; h=From:Subject:To:Cc:Message-Id:References:In-Reply-To:Feedback-ID: Date:MIME-Version:Content-Type:Content-Transfer-Encoding:CC:Date: Subject:From; b=NrP3UO/9fBXGKR4Ku1lCHVLa7s+rlj3J6BOgGNZDFxCluPbeqRNe1ErnKNXRbymDE 3JCwFrcgz69RvArhNHKIs8UXkgbe9ky+RE6Mvvscrro3efntXmhuyyddKaSGLYS+yu 2o7mU5jXNh+wOhK5SIegT3S1w4PfpdCHSq4url3sIuddnsIhhigN07NFpLXOENeLSV vMOaFx6w2QgZVJYEqFF1SzxGXm9htmtuVwK2U6gzsdBcap13403C+WEFcNfZYXHA1C V73+gY3msGvylhEOrOi99CYixd0bdPRT2h7OvGF/wwNoKbd6N840IRxNVQKmXtG81z XcTV+vZ2t5chw== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=vates.tech; s=mte1; t=1774344481; x=1774604981; i=anthony.perard@vates.tech; bh=xySpiGsL6jhSgBQryanlxjULqiUOOXBfzlvPnW3Iw4Y=; h=From:Subject:To:Cc:Message-Id:References:In-Reply-To:Feedback-ID: Date:MIME-Version:Content-Type:Content-Transfer-Encoding:CC:Date: Subject:From; b=VFzxfT/ubcO/+ueQrA8nkBkMxDi9DO/dJ04dv0/Amnr3wau6PwP5EcGLKNxtNbdf0 MTJWSE7jKcnxN7YmwJrM1ZZnLYbeFx19sunrr7LDEoYuSBa1frsUP/U5fODYrqsjJ8 jDXpnqSiJEY4tKQLXvWMydD6C5nFT7PuzjFe3JfxLbeIlXI+fHZOMZSALNQh1V2DGj UZp3I0Ro5Gnk18rYd/+XcCqc0TIx3N0hqMtcKcxo/2+YheDdElTBrsWAM/3MtIM+xC aRz4OVF0rOFDOO2i0XaSQmBVHoX+G/rv1ITU+UrHfGxnL79nQUvsp/yjcTCDFw7tfA zwGCh2E9yreJg== Received: from pmta11.mandrill.prod.suw01.rsglab.com (localhost [127.0.0.1]) by mail180-47.suw31.mandrillapp.com (Mailchimp) with ESMTP id 4fg4TD6rbFzPm0dZq for ; Tue, 24 Mar 2026 09:28:00 +0000 (GMT) From: "Anthony PERARD" Subject: =?utf-8?Q?Re:=20[PATCH=200/4]=20Xen:=20Add=20Q35=20initial=20support=20for=20HVM=20guests?= Received: from [37.26.189.201] by mandrillapp.com id 87f83ede378c4c789f06918e21d30ead; Tue, 24 Mar 2026 09:28:00 +0000 X-Bm-Disclaimer: Yes X-Bm-Milter-Handled: 4ffbd6c1-ee69-4e1b-aabd-f977039bd3e2 X-Bm-Transport-Timestamp: 1774344479469 To: "=?utf-8?Q?Marek=20Marczykowski-G=C3=B3recki?=" Cc: "Thierry Escande" , qemu-devel@nongnu.org, "Paolo Bonzini" , "Richard Henderson" , "Michael S. Tsirkin" , "Eduardo Habkost" , xen-devel@lists.xenproject.org Message-Id: References: <20260313164649.794591-1-thierry.escande@vates.tech> In-Reply-To: X-Native-Encoded: 1 X-Report-Abuse: =?UTF-8?Q?Please=20forward=20a=20copy=20of=20this=20message, =20including=20all=20headers, =20to=20abuse@mandrill.com.=20You=20can=20also=20report=20abuse=20here:=20https://mandrillapp.com/contact/abuse=3Fid=3D30504962.87f83ede378c4c789f06918e21d30ead?= X-Mandrill-User: md_30504962 Feedback-ID: 30504962:30504962.20260324:md Date: Tue, 24 Mar 2026 09:28:00 +0000 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=198.2.180.47; envelope-from=bounce-md_30504962.69c25920.v1-87f83ede378c4c789f06918e21d30ead@bounce.vates.tech; helo=mail180-47.suw31.mandrillapp.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_MED=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, 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 On Sat, Mar 14, 2026 at 03:16:15PM +0100, Marek Marczykowski-G=C3=B3recki w= rote: > On Fri, Mar 13, 2026 at 04:46:56PM +0000, Thierry Escande wrote: > > This patch series introduces Q35 chipset support for Xen HVM guests. Th= is is > > based on the work from Alexey Gerasimenko (See patchset [1] for referen= ce). > > > > This series does not implement device passthrough as this will need mor= e work > > on the Xen side to support multiple PCI buses. Since Q35 chipset does n= ot > > support device hotplugging and with current Xen mechanism for device > > passthrough, they have to be plugged to a new PCIe root port, i.e. not = the PCI > > bus 0. > > I always found it weird that Xen does hot-plugging of PCI passthrough > devices... Wouldn't it be easier to change this (connect them from the > very start, via QEMU cmdline) and declare hotplug as unsupported (at > least at this time)? I realize it's more complex change at the toolstack > side, but overall may simplify things and maybe even improve > reliability. Skipping hot-plug on Q35 sounds good to me. I though we could keep using QMP to do cold plug, with the experimental "--preconfig", but "device_add" isn't allowed :-(. So yes, doing this via command line sounds fine. In libxl, we might be able to transform the json for `device_add` into the command line counterpart for `-device` fairly easily so the argument are only generated in a single place. Then we could skip the QMP "device_add" in libxl when it's already done via command line. But looks like XCP-ng also does QMP "device_add" for passthrough :-( but one step-at a time. Cheers, -- Anthony Perard | Vates XCP-ng Developer XCP-ng & Xen Orchestra - Vates solutions web: https://vates.tech