From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58442) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDwLk-0006I9-8K for qemu-devel@nongnu.org; Fri, 17 Jun 2016 12:10:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bDwLh-0005hR-VG for qemu-devel@nongnu.org; Fri, 17 Jun 2016 12:10:27 -0400 Date: Fri, 17 Jun 2016 17:10:16 +0100 From: "Richard W.M. Jones" Message-ID: <20160617161016.GU16797@redhat.com> References: <20160526144629.GH28935@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Qemu-devel] [PATCH] hw/arm/virt: Reject gic-version=host for non-KVM List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell Cc: Cole Robinson , QEMU Developers , qemu-arm On Fri, Jun 17, 2016 at 03:49:38PM +0100, Peter Maydell wrote: > On 26 May 2016 at 15:53, Peter Maydell wrote: > > On 26 May 2016 at 15:46, Richard W.M. Jones wrote: > >> The problem with this is if I'm using TCG fallback mode, how > >> can I specify the right gic-version? ie: > >> > >> -M virt,gic-version=host,accel=kvm:tcg > >> > >> Only qemu knows if KVM is going to be enabled. > >> > >> The same problem happens with '-cpu host' BTW. I really want a "make > >> it work" option, as I've said on several previous occasions on this > >> list eg: > >> https://lists.nongnu.org/archive/html/qemu-devel/2014-08/msg04173.html > > > > I agree that we really need to do better here (thinking about > > the problem is on my todo list but generally other more pressing > > issues intervene). I'd welcome suggestions for semantics which > > (a) do what you want (b) are reasonably in line with what we do > > on other host architectures (c) don't break existing command lines. > > (I think those are the main requirements.) > > ...so does anybody have any concrete suggestions? We could fix > this for 2.7 but we're starting to run low on time for that. I have changed libguestfs so it tries to guess if KVM will be used or not. We have to do this for the -cpu option too, but the guess is not too reliable. Only QEMU has the actual knowledge we need. https://github.com/libguestfs/libguestfs/commit/7023f20830a681ef36f8f99415fe41791555a3db Can we not have a "give me a GIC which will work" option, eg. -M virt,gic-version=besteffort,accel=kvm:tcg I don't care if it's not the fastest or most featureful. Rich. -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones Read my programming and virtualization blog: http://rwmj.wordpress.com virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top