From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gerd Hoffmann Subject: Re: pv clock: kvm is incompatible with xen :-( Date: Mon, 21 Apr 2008 14:50:22 +0200 Message-ID: <480C8D8E.6000305@redhat.com> References: <47FF1441.6010801@redhat.com> <47FF545C.3010107@qumranet.com> <47FF6B43.1070305@redhat.com> <47FFB5B9.2020904@goop.org> <4808AF8C.5010500@redhat.com> <48091F6D.7030600@goop.org> <480C42E0.3040307@redhat.com> <480C7E82.1010402@goop.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: kvm-devel , Avi Kivity , Glauber de Oliveira Costa To: Jeremy Fitzhardinge Return-path: In-Reply-To: <480C7E82.1010402@goop.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org Jeremy Fitzhardinge wrote: > Xen could change the parameters in the instant after get_time_values(). > That change could be as a result of suspend-resume, so the parameters > and the tsc could be wildly different. Ah, ok, forgot the rdtsc in the picture. With that in mind I fully agree that the loop is needed. I think kvm guests can even hit that one with the vcpu migrating to a different physical cpu, so we better handle it correctly ;) > Sure, but get_time_values() has several other callers. Not really. There are only two calls, one in clocksource_read() and one in the init path. The later is superfluous I think because clocksource_read() is the only user of the shadowed time info. cheers, Gerd -- http://kraxel.fedorapeople.org/xenner/ ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone