From mboxrd@z Thu Jan 1 00:00:00 1970 From: Carsten Otte Subject: Re: RFC: multiple address spaces for one process Date: Sat, 30 Jun 2007 06:19:21 +0200 Message-ID: <4685D9C9.20504@de.ibm.com> References: <87myynt1m6.wl%peter@chubb.wattle.id.au> <468517E1.4050803@goop.org> Reply-To: carsteno@de.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <468517E1.4050803@goop.org> 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: linux-mm@kvack.org, Peter Chubb , virtualization@lists.linux-foundation.org List-Id: virtualization@lists.linuxfoundation.org Jeremy Fitzhardinge wrote: > It might be interesting if the two cases could be unified in some way, > so that the VMMs could use a common usermode mechanism to achieve the > same end, which is what Carsten was proposing. But its not obvious to > me how much common mechanism can be pulled out, since its a pretty > deeply architecture-specific operation. The big difference here is that LinuxOnLinux does represent guest virtual addressing in these mm structs where all other kernel based VMMs do represent guest physical in the user address space. That somewhat disqualifies LinuxOnLinux to share the commonality. Whether or not proposed patch makes sense for shaddow page tables is unknown to me, since we have nested paging on s390.