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.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 6199DC83F15 for ; Wed, 30 Aug 2023 16:57:08 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.593170.926102 (Exim 4.92) (envelope-from ) id 1qbOUm-0002eO-Au; Wed, 30 Aug 2023 16:56:44 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 593170.926102; Wed, 30 Aug 2023 16:56:44 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qbOUm-0002eH-7T; Wed, 30 Aug 2023 16:56:44 +0000 Received: by outflank-mailman (input) for mailman id 593170; Wed, 30 Aug 2023 16:56:43 +0000 Received: from se1-gles-sth1-in.inumbo.com ([159.253.27.254] helo=se1-gles-sth1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1qbOUl-0002eB-Ec for xen-devel@lists.xenproject.org; Wed, 30 Aug 2023 16:56:43 +0000 Received: from mail-wr1-x42c.google.com (mail-wr1-x42c.google.com [2a00:1450:4864:20::42c]) by se1-gles-sth1.inumbo.com (Halon) with ESMTPS id 309c0c3f-4756-11ee-8783-cb3800f73035; Wed, 30 Aug 2023 18:56:40 +0200 (CEST) Received: by mail-wr1-x42c.google.com with SMTP id ffacd0b85a97d-307d20548adso4931116f8f.0 for ; Wed, 30 Aug 2023 09:56:40 -0700 (PDT) Received: from zen.linaroharston ([85.9.250.243]) by smtp.gmail.com with ESMTPSA id x14-20020a05600c2a4e00b003fed70fb09dsm2797536wme.26.2023.08.30.09.56.39 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 30 Aug 2023 09:56:39 -0700 (PDT) Received: from zen (localhost [127.0.0.1]) by zen.linaroharston (Postfix) with ESMTP id 09DFB1FFBB; Wed, 30 Aug 2023 17:56:39 +0100 (BST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 309c0c3f-4756-11ee-8783-cb3800f73035 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1693414600; x=1694019400; darn=lists.xenproject.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:user-agent:from:to:cc:subject:date:message-id:reply-to; bh=k1Xb31+XM7zyf4p96PIo9CJeeb1rikbvP4JHVrcSM/U=; b=vXrdcVGoawYtV0sS1kQMveUCkMocu24LkkZzHbcCv0O1TSFpoOvs8zFAgyl0neNHkb yaGVNnc/OhiP0mCU2Cmq9zxuCJgQCK4RZmTAXlGvgexOxkPTHECbz8+6pkInqhGqTCF9 acrPQNO4WIsuPrVn9MOLuEDrGp2T3ylh9UJ+pjShKJd22OUp4YKYZjzsL1HFZaXjTH7s K3rAl2G7JSqv/BDozKZAyF5DHmRggk9Ep7q7+TGy9u2Ay520P9aYEPkiM3XQVP8gJhs5 kcbBGKz1Iwgs3+A7KbCO8WajR9r+pPaQYL9B4BVxyoPj54/52qLX56u2CcrTNgGgVvJS KB7A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1693414600; x=1694019400; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:user-agent:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=k1Xb31+XM7zyf4p96PIo9CJeeb1rikbvP4JHVrcSM/U=; b=XjVHNInDaARnv0exXw0Y+lIMuGN4/WMznSEkvsrVy41JVEtuveeJmc8kjCRyL56WNU ziUELhYK8voy6B9wo17ddNsvn0s6qxJOTsyRHwMjRCvQRARHNiDYD6xkHUOZcBQTNW0u CAv52ZS0t02KHZBX//LdsyNUlr6dhcdU5kLz5xMV8RHwT4FYtivifqeOXhJKJLksLT2R W9CIhFA7trMz76B9mjZTDVXHB1N717iEHq/NR+nBhqzbG7x2oXB1YfjrvuK6zSODRc7J xLivqwcXGwnn8JY6TLgP6m/DUbn3py9M/FVlXUqGSyVcBp2t/qQ4Xfex6/041PQXbeb8 BODw== X-Gm-Message-State: AOJu0Ywj9YxWL614O4WCwlrcwcvLndfUdvyU5kPXsrFsX/UXQlvu2R85 gZGt3Zm04KkBIG+LoFghRfwDFw== X-Google-Smtp-Source: AGHT+IHGgTVU+REc/aEIU4qFjHGblxDqda4AQyqsdIdkvvPCfEUq+PlwvQDCu10lcyi+JsaaB31q1A== X-Received: by 2002:a5d:6108:0:b0:317:7eec:5e9d with SMTP id v8-20020a5d6108000000b003177eec5e9dmr2314014wrt.16.1693414599909; Wed, 30 Aug 2023 09:56:39 -0700 (PDT) User-agent: mu4e 1.11.16; emacs 29.1.50 From: Alex =?utf-8?Q?Benn=C3=A9e?= To: Xen-devel , Stewart Hildebrand , Viresh Kumar , Volodymyr Babchuk , Sergiy Kibrik Cc: QEMU Developers , Vikram Garhwal , Stefano Stabellini , Marcin Juszkiewicz , Jonathan Cameron Subject: QEMU features useful for Xen development? Date: Wed, 30 Aug 2023 17:11:02 +0100 Message-ID: <87y1hspiyh.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Dear Xen community, Linaro is significantly invested in QEMU development, with a special focus on Arm-related aspects. We recognize the value of QEMU as a readily available software reference platform for projects that need to test their software well before the availability of real hardware. The primary focus of our effort is on adding core architectural elements to the CPU emulation. For an overview of the current feature set, please see: https://qemu.readthedocs.io/en/master/system/arm/emulation.html Besides the -cpu max, providing an approximation of a v9.0 baseline CPU, we have also recently added several specific CPU types like the Neoverse-N1 and V1 processor types as well as numerous Cortex CPU models. Our most utilized machine model is "virt", which is primarily designed for guest operation and therefore has minimal resemblance to actual hardware. "sbsa-ref" was implemented to more closely simulate a real machine that aligns with Arm's SBSA specification. In our work on VirtIO, we often use QEMU. Most of our rust-vmm vhost-device backends, for instance, were initially tested on QEMU. Now that everyone is up-to-date, I would welcome any feedback from the Xen community on features that would increase QEMU's usefulness as a development target. Do you have interest in any upcoming Arm CPU features? For example, we recently added FEAT_RME support for Arm's new confidential computing, but currently do not implement FEAT_NV/NV2. How about the HW emulation in QEMU? Is the PCI emulation reliable enough to ensure confidence while testing changes to Xen's PCI management? What about the few peripherals that the hypervisor accesses directly? Are there other development features you consider essential? Have you noticed any limitations with gdbstub? Does anyone use the record/replay or reverse debug functions? Has anyone tried TCG plugins for analysing the behavior of the hypervisor? While I cannot promise to implement every wish-list item (performance counter emulation, for example, as we are not a uArch simulator), I am eager to gather feedback on how QEMU could be improved to help the Xen community deliver it's roadmap faster. Thank you for your time and I look forward to any feedback :-) --=20 Alex Benn=C3=A9e Virtualisation Tech Lead @ Linaro