From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sheng Yang Subject: Re: 2.6.27.5 guest boot failure using in-kernel PIT Date: Fri, 21 Nov 2008 11:05:26 +0800 Message-ID: <200811211105.26595.sheng@linux.intel.com> References: <20081120142253.GA30825@blackpad> <20081120220517.GB30825@blackpad> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: Eduardo Habkost To: kvm@vger.kernel.org Return-path: Received: from mga12.intel.com ([143.182.124.36]:2005 "EHLO azsmga102.ch.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753103AbYKUDJH (ORCPT ); Thu, 20 Nov 2008 22:09:07 -0500 In-Reply-To: <20081120220517.GB30825@blackpad> Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-ID: On Friday 21 November 2008 06:05:17 Eduardo Habkost wrote: > On Thu, Nov 20, 2008 at 12:22:53PM -0200, Eduardo Habkost wrote: > > Hi, > > > > When using a kvm.git kernel as host, I am getting guest boot failures > > when booting Fedora Rawhide kernel (2.6.27.5-117.fc10.x86_64). Guest > > stops booting at: > > > > ENABLING IO-APIC IRQs > > ..TIMER: vector=0x30 apic1=0 pin1=0 apic2=-1 pin2=-1 > > ..MP-BIOS bug: 8254 timer not connected to IO-APIC > > ...trying to set up timer (IRQ0) through the 8259A ... > > ..... (found apic 0 pin 0) ... > > ....... failed. > > ...trying to set up timer as Virtual Wire IRQ... > > ..... failed. > > ...trying to set up timer as ExtINT IRQ... > > I've just found out this problem happens because the guest has HZ=1000 > and the host had HZ=250 and no CONFIG_HIGH_RES_TIMERS. > > With this setup, the host is not managing to inject enough timer > interrupts during the mdelay() loop on timer_irq_works(). So, do we need to depend on CONFIG_HIGH_RES_TIMERS? I think most modern machine should have this. -- regards Yang, Sheng