From owner-freebsd-xen@FreeBSD.ORG Thu May 28 04:50:03 2009 Return-Path: Delivered-To: freebsd-xen@hub.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 61ABD106566C for ; Thu, 28 May 2009 04:50:03 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (freefall.freebsd.org [IPv6:2001:4f8:fff6::28]) by mx1.freebsd.org (Postfix) with ESMTP id 4FE2B8FC14 for ; Thu, 28 May 2009 04:50:03 +0000 (UTC) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (gnats@localhost [127.0.0.1]) by freefall.freebsd.org (8.14.3/8.14.3) with ESMTP id n4S4o3dt041632 for ; Thu, 28 May 2009 04:50:03 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.14.3/8.14.3/Submit) id n4S4o3EJ041623; Thu, 28 May 2009 04:50:03 GMT (envelope-from gnats) Date: Thu, 28 May 2009 04:50:03 GMT Message-Id: <200905280450.n4S4o3EJ041623@freefall.freebsd.org> To: freebsd-xen@FreeBSD.org From: Adrian Chadd Cc: Subject: Re: kern/135008: FreeBSD-current/Xen timecounter jumps X-BeenThere: freebsd-xen@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: Adrian Chadd List-Id: Discussion of the freebsd port to xen - implementation and usage List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 28 May 2009 04:50:03 -0000 The following reply was made to PR kern/135008; it has been noted by GNATS. From: Adrian Chadd To: bug-followup@freebsd.org Cc: Subject: Re: kern/135008: FreeBSD-current/Xen timecounter jumps Date: Thu, 28 May 2009 12:25:45 +0800 .. now that the RTC code is in and I've figured out whats going on there, the problem has become obvious. Changing the dom0 clock by > 1 second seems to trigger a re-read of the wall clock in the DomU. The DomU sets the TOD to the wall clock - but this unfortunately sets it to the hypervisor start time rather than including the start time + uptime. The fix is to figure out the code path(s) in the xen clock code and fix the TOD update to be correct.