From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andi Kleen Subject: Re: The virtuailization patches break Voyager. Date: Sat, 28 Apr 2007 10:42:48 +0200 Message-ID: <200704281042.48440.ak@suse.de> References: <4632FD3E.401@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4632FD3E.401@goop.org> Content-Disposition: inline List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Jeremy Fitzhardinge Cc: James.Bottomley@hansenpartnership.com, virtualization@lists.osdl.org, "Eric W. Biederman" , "H. Peter Anvin" , Andrew Morton , Thomas Gleixner List-Id: virtualization@lists.linuxfoundation.org On Saturday 28 April 2007 09:52:30 Jeremy Fitzhardinge wrote: > Eric W. Biederman wrote: > > Next time I'm in a really tormenting mood I will fire up my > > my ibm ps2 with it's 16Mhz 386 and 6MB and verify that all is working > > well there. > > > > Well, that would be interesting. From a subarch perspective, it would > just be the normal default, and in theory it should work fine. But I > suspect the fpu emulator is probably broken, and non-WP is likely to > have rotted, AFAIK it's been tested occasionally on some embedded 386 systems (e.g. by Thomas Gleixner). Probably not with the recent changes though. > and lots of other things. Is that an MCA machine? Yes should be. > > I really don't think it is ok to be cavalier about anything > > that we actually support. Usually if we can handle the general > > case it makes for better more maintainable code. > > > > So far the paravirt class of machines seems every bit as much a subarch > > as voyager and every bit as interesting. > > > Well, not really. The problem with the subarch mechanism is that it > promotes a lot of copied code with small modifications, and so making > changes is the inherently non-general activity of trying to find all the > various copies, work out what subtle differences they have, and try to > make the appropriate changes in each case. This was one of the major > objections to the original Xen-as-subarch patches, and it is the problem > with Voyager. The mass of preprocessor tricks doesn't help either. Yes I agree. Current i386 subarch is a mess and I hope to slowly phase it out. mach-{es7000,summit} should just be folded into mach-generic always (like x86-64) and I'm somewhat hoping that mach-voyager and perhaps mach-visws too will just go away at some point. The future direction are focussed pluggable interfaces like genapic, smp_ops etc. -Andi