From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ivan Kelly Subject: Re: Guest OS without paging Date: Mon, 7 Nov 2005 18:54:26 +0000 Message-ID: <20051107185425.GC7339@localhost.localdomain> References: <20051107001154.GA10721@localhost.localdomain> <200511071425.50611.mark.williamson@cl.cam.ac.uk> <20051107170632.GB7339@localhost.localdomain> <200511071726.20118.mark.williamson@cl.cam.ac.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <200511071726.20118.mark.williamson@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: Mark Williamson Cc: Ivan Kelly , xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org On Mon, Nov 07, 2005 at 05:26:19PM +0000, Mark Williamson wrote: > I guess I'm not clear what memory model you need for Minix, can you clarify? > What version of Minix is this? Does it really not do any virtual memory of > its own? Does it do any tricks at all (demand paging? page sharing?), or > does it run unpaged or something else? well, minix uses segmentation but doesn't use paging at all, because it's build to be portable and not all processers have a mmu unit(i think the arm doesn't and such). Im using minix 3. > > Domains get a hard allocation of real memory, so when the pages get populated > is entirely up to the guest; Xen won't interfere. What about page faults? Will I have to have to write code to handle these, or can I assume that since im only ever using memory thats alreayd mapped, page faults wont occur? > > If you essentially want to pretend you've got a flat, unpaged address space > then you should be able to just be able to build a set of page tables (for > instance in your custom builder) and then pretend they're not there. Just > remember that you can't use the very top part of the address space because > Xen will be mapped there. Thats exactly what I want. Does the 64M address space need to have entries in my page table or can i just make my guest's pagetable from 64M-xxM. Also, is there are any pages allocated in this 64M address space, will they my allocated from the domains pool of page frames, or from dom0's? Best regards Ivan