From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 2/3] kvmclock - the host part. Date: Tue, 13 Nov 2007 16:44:43 +0200 Message-ID: <4739B85B.2080102@qumranet.com> References: <11945615632624-git-send-email-gcosta@redhat.com> <11945615703593-git-send-email-gcosta@redhat.com> <11945615751747-git-send-email-gcosta@redhat.com> <4736D6C0.8040408@qumranet.com> <47398A68.8080009@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org, jeremy-TSDbQ3PG+2Y@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, hollisb-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org To: Glauber de Oliveira Costa Return-path: In-Reply-To: <47398A68.8080009-H+wXaHxf7aLQT0dZR+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 Glauber de Oliveira Costa wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Avi Kivity escreveu: > >> Glauber de Oliveira Costa wrote: >> >>> This is the host part of kvm clocksource implementation. As it does >>> not include clockevents, it is a fairly simple implementation. We >>> only have to register a per-vcpu area, and start writting to it >>> periodically. >>> >>> >>> >> Missing live migration support (a way for userspace to read and write >> the guest clock address). Should probably be in a separate patch. >> > > I think it's a matter of issuing a hypercall for reading the clock > address. It's fair simple, and can be done in a later version of this patch. > As for writting, the register hypercall itself can be used. It has no > special side-effects we should care about. > kvm live migration is done (at least thus far) without guest involvement. So you need the host to be able to transfer this state. > >>> @@ -1924,6 +1955,7 @@ out: >>> goto preempted; >>> } >>> >>> + kvm_write_guest_time(vcpu); >>> post_kvm_run_save(vcpu, kvm_run); >>> >>> >> Why here? Seems like we're leaving the guest for a while at this place. >> >> Suggest putting it on top of __vcpu_run(), guarded by a flag, and >> setting the flag every time we put the vcpu. >> > > No special preference. It just sounded exity enough to me. I can move to > where you suggest. > > It's more than a place, it's a set of rules: - if the vcpu is migrated, we need a new timebase - ditto if we're descheduled (well that's the same thing) - if "some time passes" -- 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/