From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56942) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cOSXJ-0007JF-Jy for qemu-devel@nongnu.org; Tue, 03 Jan 2017 12:06:10 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cOSXG-0004Wd-Eu for qemu-devel@nongnu.org; Tue, 03 Jan 2017 12:06:09 -0500 Received: from mx1.redhat.com ([209.132.183.28]:44630) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1cOSXG-0004Vc-95 for qemu-devel@nongnu.org; Tue, 03 Jan 2017 12:06:06 -0500 Date: Tue, 3 Jan 2017 15:06:02 -0200 From: Eduardo Habkost Message-ID: <20170103170602.GD3315@thinpad.lan.raisama.net> References: <20161229223815.13705-1-ehabkost@redhat.com> <20161230152834.6d1fa963@Igors-MacBook-Pro.local> <20161230182308.GK3441@thinpad.lan.raisama.net> <20170103140252.1a2df147@nial.brq.redhat.com> <20170103142223.GB3315@thinpad.lan.raisama.net> <20170103175327.61778555@Igors-MacBook-Pro.local> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170103175327.61778555@Igors-MacBook-Pro.local> Subject: Re: [Qemu-devel] [PATCH] qdev: Make "hotplugged" property read-only List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Igor Mammedov Cc: Paolo Bonzini , qemu-devel@nongnu.org, "Michael S. Tsirkin" , Markus Armbruster , Andreas =?iso-8859-1?Q?F=E4rber?= , libvir-list@redhat.com, Laine Stump (CCing libvir-list and Laine) On Tue, Jan 03, 2017 at 05:53:27PM +0100, Igor Mammedov wrote: > On Tue, 3 Jan 2017 17:10:15 +0100 > Paolo Bonzini wrote: > > > > > > > On 03/01/2017 15:22, Eduardo Habkost wrote: > > >> I didn't know that. Is this documented somewhere? > > >> Is it actually used by any existing software? > > > not that I know of. But users should be fixed if they are not using it. > > > > > > I see. The problem is that the mechanism is undocumented, > > > untested, and seems very likely to trigger bugs in device code. > > > > I agree. Why can't hotplugged be migrated? > It's probably not migrated because of it's not runtime/guest modified > state so we don't have to migrate it as it's know in advance. > > For now it should set manually on CLI (-device) with the rest of > hotplugged device properties. As this recommendation has the potential to trigger hidden bugs (and known to trigger a bug in QEMU <= 2.8), I would like it to be properly documented, and the documentation/recommendations reviewed following the usual patch review process. While we don't do that, setting "hotplugged=true" on the command-line is an unused, undocumented, untested (and unsupported?) feature. -- Eduardo