From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Petazzoni Date: Sun, 19 Oct 2014 22:54:51 +0200 Subject: [Buildroot] [PATCH 1/3] qemu-system: new package In-Reply-To: <54441E9F.8080802@mind.be> References: <1399148415-27648-1-git-send-email-gustavo@zacarias.com.ar> <20141012171752.29414e94@free-electrons.com> <543AD090.3000107@zacarias.com.ar> <543EA87A.2050204@mind.be> <543FCDD6.9070104@zacarias.com.ar> <54419C9C.7050705@mind.be> <5441BEDE.1000102@zacarias.com.ar> <54441E9F.8080802@mind.be> Message-ID: <20141019225451.3aa6176e@free-electrons.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: buildroot@busybox.net Dear Arnout Vandecappelle, On Sun, 19 Oct 2014 22:27:11 +0200, Arnout Vandecappelle wrote: > > The only shared code in qemu for user vs. system is just basically CPU > > emulation. > > For system you've got all of the hardware (audio/ hw/ net/ directories > > and so on) which isn't used by user at all. > > For user it deals with what we can call "ABI" (userland, linux-user/ dir > > in qemu) which isn't used by system at all, and has arch bits as well. > > When there are system emulations broken with the latest version of qemu > > it isn't necessarily a problem with the cpu emulation, the same can > > happen to user emulation without affecting system. > > So if you're like 100% sure user both will work right if system does for > > X version go ahead, i don't think it's a safe assumption. > > Just google around a bit: > > https://bugs.launchpad.net/ubuntu/+source/qemu/+bug/1284344 > > https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=668658 > > So what I hear you say is that there really is a case for specifying the > qemu-user and qemu-system version separately, and that that's what this whole > discussion really is about. And I guess you may want to build at the same time a > host-qemu-user of one version and a host-qemu-system of another version, correct? > > Still, the .mk file of qemu-user and qemu-system are 90% the same. It would be > nice to be able to factor that out somehow. However, it makes complete sense to > have them as separate packages first and merge them later. > > So the question is: is the need for separate host-qemu-system and > host-qemu-user versions more important than the additional complexity of > specifying a nearly-identical .mk file twice? Despite Gustavo's explanation, I'm not sure to see what is the need to have a different version for host-qemu-system and host-qemu-user. If a given version of host-qemu-system works for a given architecture/platform, then surely, host-qemu-user should work for the same architecture. The opposite is obviously not true, but it doesn't matter much: we can keep whatever version gets host-qemu-system working. Thomas -- Thomas Petazzoni, CTO, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com