From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51093) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1crM9t-0002p4-Sk for qemu-devel@nongnu.org; Fri, 24 Mar 2017 06:09:26 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1crM9s-0001Db-VE for qemu-devel@nongnu.org; Fri, 24 Mar 2017 06:09:25 -0400 Received: from mail-wr0-x22a.google.com ([2a00:1450:400c:c0c::22a]:35520) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1crM9s-0001DU-PF for qemu-devel@nongnu.org; Fri, 24 Mar 2017 06:09:24 -0400 Received: by mail-wr0-x22a.google.com with SMTP id u1so6106712wra.2 for ; Fri, 24 Mar 2017 03:09:24 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <0596af14-a95c-edbf-1441-2f1a39bdff99@suse.com> References: <20170323212848.8492-1-ehabkost@redhat.com> <20170323212848.8492-2-ehabkost@redhat.com> <0596af14-a95c-edbf-1441-2f1a39bdff99@suse.com> From: Peter Maydell Date: Fri, 24 Mar 2017 10:09:03 +0000 Message-ID: Content-Type: text/plain; charset=UTF-8 Subject: Re: [Qemu-devel] [RFC 1/4] [UNTESTED] xen: Don't force has_dynamic_sysbus on machine class List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Juergen Gross Cc: Eduardo Habkost , QEMU Developers , Marcel Apfelbaum , Thomas Huth , Stefano Stabellini , Laszlo Ersek , Markus Armbruster On 24 March 2017 at 08:23, Juergen Gross wrote: > On 23/03/17 22:28, Eduardo Habkost wrote: >> The xen-backend devices created by the Xen code are not supposed >> to be treated as dynamic sysbus devices. This is an attempt to >> change that and see what happens, but I couldn't test it because >> I don't have a Xen host set up. >> >> If this patch breaks anything, this means we have a bug in >> foreach_dynamic_sysbus_device(), which is supposed to return only >> devices created using -device. >> >> The original code that sets has_dynamic_sysbus was added by >> commit 3a6c9172ac5951e6dac2b3f6cbce3cfccdec5894, but I don't see >> any comment explaining why it was necessary. > > xen-backend devices are created via qmp commands when attaching new > pv-devices to a domain. They can be dynamically removed, too. Setting > has_dynamic_sysbus was necessary to support this feature. This seems like it ought to be handled by marking the xen-backend devices as being ok-to-dynamically-create somehow, not by marking the machine as supporting dynamic-sysbus (which it doesn't). Maybe we don't have the necessary support code to do that though? thanks -- PMM