From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [kvm-ppc-devel] RFC/patch portability: split kvm_vm_ioctl v2 Date: Fri, 26 Oct 2007 13:47:14 +0200 Message-ID: <4721D3C2.8090407@qumranet.com> References: <1192192452.7630.16.camel@cotte.boeblingen.de.ibm.com> <1193327325.8345.9.camel@cotte.boeblingen.de.ibm.com> <1193327326.3284.2.camel@izike-woof.qumranet.com> <1193329322.28279.21.camel@basalt> <472114B6.6080000@qumranet.com> <1193345465.28279.47.camel@basalt> <4721A185.1070808@qumranet.com> <4721A3A3.8020504@de.ibm.com> <4721A82A.2040402@de.ibm.com> <4721B1ED.6040006@qumranet.com> <4721C1DB.3040207@de.ibm.com> <4721C330.3030302@qumranet.com> <4721C47E.30800@de.ibm.com> <4721C53E.1070507@qumranet.com> <4721D344.2020508@de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: "kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org" , kvm-ppc-devel , carsteno-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, Hollis Blanchard , "Zhang, Xiantao" To: carsteno-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org Return-path: In-Reply-To: <4721D344.2020508-tA70FqPdS9bQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org Errors-To: kvm-devel-bounces-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: kvm.vger.kernel.org Carsten Otte wrote: > Avi Kivity wrote: >> Why aren't memory slots common too? Only their number is different, >> while the implementation is the same. > Your approach makes the meaning of memory slot somewhat useless on > s390, if that one may be sparse and may be result of different > allocations: On x86, there has to be one memory slot per allocation, > versus on s390 there has to be exactly one memory slot with multiple > allocations behind. No, a memory slot can span multiple backing stores. But it must be contiguous in both the host userspace and guest physical address spaces. > > For userspace that means, with your approach it has to do total > different memory setup for different archs _if_ it wants to use > multiple allocations and/or sparse: > - on x86 it does allocations to random userspace address, and > registers each of them as memory slot > - on s390 it does allocations to a specific address layout similar to > the guest, and registers only one memory slot for the whole thing > > With Izik's approach however, this is transparent to userspace: it has > multiple memory slots, one per allocation. Regardless of the CPU > architecture. You can do this with the current memory slots as well. Although I'm feeling that I misunderstood Izik's idea. I'll go talk to him. -- error compiling committee.c: too many arguments to function ------------------------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Still grepping through log files to find problems? Stop. Now Search log events and configuration files using AJAX and a browser. Download your FREE copy of Splunk now >> http://get.splunk.com/