From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerd Knorr Subject: Re: Hypercall interface changes for PAE Date: Tue, 31 May 2005 21:02:08 +0200 Message-ID: <20050531190208.GA28168@bytesex> References: <20050530125247.GA12140@bytesex> <61adb21cca3abe8c474f66040037da6a@cl.cam.ac.uk> <20050531101851.GB22211@bytesex> <20050531113614.GB22913@bytesex> <15fad2b24c731550fee5cffc747ae3c9@cl.cam.ac.uk> <8013a228218edd6c3b74a5b5974e0553@cl.cam.ac.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <8013a228218edd6c3b74a5b5974e0553@cl.cam.ac.uk> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser Cc: xen-devel List List-Id: xen-devel@lists.xenproject.org On Tue, May 31, 2005 at 07:26:51PM +0100, Keir Fraser wrote: > > On 31 May 2005, at 19:21, Keir Fraser wrote: > > >The downside of this approach is that the C declarations of > >mmu_update_t, update_va_mapping, etc are different on 32-bit PAE > >builds. But only low-level guest code will touch those interfaces > >anyway, and there is unlikely to be code sharing between PAE and > >non-PAE at that level. > > > >What do you think? > > Actually, we could export intpte_t and physaddr_t at the guest > interface and declare mmu_update_t and friends in terms of those > typedefs. This would also avoid needing different wrapper > implementations of those hypercalls within Xen itself. Neat. :-) That certainly would be the way to go if we want to have different interfaces for PAE and non-PAE. I'm not sure it is a good idea to have different hypercall interfaces for PAE and non-PAE cases in the first place. What does this mean for the tools? Would these also be either PAE or non-PAE then? What about the option to maybe run non-PAE guests in PAE-xen in some translated shadow mode? That wouldn't work then. I don't think this would be a big problem though ... Gerd -- -mm seems unusually stable at present. -- akpm about 2.6.12-rc3-mm3