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 2EC0AC4332F for ; Tue, 18 Oct 2022 08:38:23 +0000 (UTC) Received: from localhost ([::1]:36564 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oki7B-0000fh-T5 for qemu-devel@archiver.kernel.org; Tue, 18 Oct 2022 04:38:21 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:36190) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1okhuJ-0004Es-1n; Tue, 18 Oct 2022 04:25:03 -0400 Received: from mail.xenproject.org ([104.130.215.37]:47912) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1okhuH-0001ch-82; Tue, 18 Oct 2022 04:25:02 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=xen.org; s=20200302mail; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:Subject: From:References:Cc:To:MIME-Version:Date:Message-ID; bh=RZV2EaUyuf7LDviRdlZ1zghsWBgRjq3ZsAcy/wHuSkU=; b=3Km7LjD/BOVMIq0yts/6nebgii slQfESAWAaNb0YGu5FfAHfeY++Wbav9WaOtjsB/8e8aog/HiWUbLZIbBkDYAAazGc8h9TI032O3fK 2SKxbgaEPUgOlmKfCdeWfTU5NplIGHeRUiWa8oXIOliI2OBXvvW/LW48mUWuBQQkTwR0=; Received: from xenbits.xenproject.org ([104.239.192.120]) by mail.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1okhu7-0004Wl-Aa; Tue, 18 Oct 2022 08:24:51 +0000 Received: from home.octic.net ([81.187.162.82] helo=[10.0.1.102]) by xenbits.xenproject.org with esmtpsa (TLS1.3:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.92) (envelope-from ) id 1okhu6-0006Sw-SW; Tue, 18 Oct 2022 08:24:51 +0000 Message-ID: <460a480e-4e91-8d78-60da-59b9cc98beee@xen.org> Date: Tue, 18 Oct 2022 09:24:48 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.3.3 To: Stefano Stabellini Cc: Vikram Garhwal , qemu-devel@nongnu.org, stefano.stabellini@amd.com, Peter Maydell , Anthony Perard , Paul Durrant , "open list:ARM TCG CPUs" , "open list:X86 Xen CPUs" References: <20221015050750.4185-1-vikram.garhwal@amd.com> <20221015050750.4185-11-vikram.garhwal@amd.com> <3e504b1b-197d-b77b-16e1-86530eb3d64c@xen.org> From: Julien Grall Subject: Re: [PATCH v1 10/12] hw/arm: introduce xenpv machine In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Received-SPF: pass client-ip=104.130.215.37; envelope-from=julien@xen.org; helo=mail.xenproject.org X-Spam_score_int: -43 X-Spam_score: -4.4 X-Spam_bar: ---- X-Spam_report: (-4.4 / 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, NICE_REPLY_A=-0.001, RCVD_IN_DNSWL_MED=-2.3, 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: 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" Hi Stefano, On 18/10/2022 02:26, Stefano Stabellini wrote: > On Sun, 16 Oct 2022, Julien Grall wrote: >> Hi, >> >> There seem to be some missing patches on xen-devel (including the cover >> letter). Is that expected? >> >> On 15/10/2022 06:07, Vikram Garhwal wrote: >>> Add a new machine xenpv which creates a IOREQ server to register/connect >>> with >>> Xen Hypervisor. >> >> I don't like the name 'xenpv' because it doesn't convey the fact that some of >> the HW may be emulated rather than para-virtualized. In fact one may only want >> to use for emulating devices. >> >> Potential name would be 'xen-arm' or re-using 'virt' but with 'accel=xen' to >> select a Xen layout. > > The benefit of 'xenpv' is that it doesn't require any changes to libxl. I am quite surprised. Looking at the code, it seems to work more by chance than it is intentional as the code is gated by libxl__need_xenpv_qemu(). So it would not start if there were no emulated devices. > It is even backward compatible so it could be used with an older version > of Xen/libxl. We don't really gain much here. IOREQ is a tech preview and anyone that wants to try it should really use the latest Xen. > Backward compatibility aside, if we come up with a > different name then we'll need changes to libxl and to manage those > changes. For instance, if we use 'xen-arm' that would mean we would need > to handle per-arch QEMU machine names. Right, so the main argument here is for simplicity in libxl Looking at how 'xenpv' is built, this is really expected to deal with PV backend rather than emulated device. I do expect some changes as we go along to be able to add emulated device. Furthermore, libxl is not the only toolstack out. So I am not convinced this is a good argument to keep the name the same. Cheers, -- Julien Grall