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 DEC66C433FE for ; Wed, 15 Dec 2021 10:17:50 +0000 (UTC) Received: from localhost ([::1]:46058 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mxRM5-0001P7-UR for qemu-devel@archiver.kernel.org; Wed, 15 Dec 2021 05:17:49 -0500 Received: from eggs.gnu.org ([209.51.188.92]:34114) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mxRLA-0008QQ-Uz for qemu-devel@nongnu.org; Wed, 15 Dec 2021 05:16:52 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:50531) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mxRL8-0003Zq-Tf for qemu-devel@nongnu.org; Wed, 15 Dec 2021 05:16:52 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1639563407; h=from:from:reply-to: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=uaKiWPhWcVv+1cn4ptwI3rwL2AvzvqyIbQhIBs5MIRY=; b=ONOSg9m0tUAtT3UMn3w92mg0Z6L0v4JkYaffAo6sGdboeiMOPDIDRIGOlr/k0WZ5DPuVlt i11FdZKPeWPkoG4UvHa51KFigbXvE7loC0MW0waaWUkoYgVA/U9QONjnJQkYhVNUPWqWgx 227DTkJX+onBMit2Q68Z06kko0UC/jA= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-121-sr1-ViNtNUGYXOnj1XMR2w-1; Wed, 15 Dec 2021 05:16:38 -0500 X-MC-Unique: sr1-ViNtNUGYXOnj1XMR2w-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 05F7A84A619; Wed, 15 Dec 2021 10:16:37 +0000 (UTC) Received: from redhat.com (unknown [10.22.8.165]) by smtp.corp.redhat.com (Postfix) with ESMTPS id D7BFC6E978; Wed, 15 Dec 2021 10:16:35 +0000 (UTC) Date: Wed, 15 Dec 2021 10:16:32 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Peter Maydell Subject: Re: Building QEMU as a shared library Message-ID: References: MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/2.1.3 (2021-09-10) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -34 X-Spam_score: -3.5 X-Spam_bar: --- X-Spam_report: (-3.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.719, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Amir Gonnen , "qemu-devel@nongnu.org" , "stefanha@redhat.com" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Wed, Dec 15, 2021 at 10:10:35AM +0000, Peter Maydell wrote: > On Wed, 15 Dec 2021 at 08:18, Amir Gonnen wrote: > > My goal is to simulate a mixed architecture system. > > > > Today QEMU strongly assumes that the simulated system is a *single architecture*. > > Changing this assumption and supporting mixed architecture in QEMU proved to be > > non-trivial and may require significant development effort. Common code such as > > TCG and others explicitly include architecture specific header files, for example. > > Yeah. This is definitely something we'd like to fix some day. It's > the approach I would prefer for getting multi-architecture machines. > > > Instead, I would like to suggest a new approach we use at Neuroblade to achieve this: > > Build QEMU as a shared library that can be loaded and used directly in a larger simulation. > > Today we build qemu-system-nios2 shared library and load it from qemu-system-x86_64 in order > > to simulate an x86_64 system that also consists of multiple nios2 cores. > > In our simulation, two independent "main" functions are running on different threads, and > > simulation synchronization is reduced to synchronizing threads. > > I agree with Stefan that you should go ahead and send the code as > an RFC patchset, but I feel like there is a lot of work required > to really get the codebase into a state where it is a clean > shared library... I expect there could end up being a big difference between "clean for use with QEMU CLI config X" vs "clean for use with all possible QEMU CLI configs" Regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|