From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matt Mackall Subject: Re: [PATCH 1/2] lguest: handle dodgy/non-existent TSC. Host code. Date: Thu, 5 Jul 2007 01:41:15 -0500 Message-ID: <20070705064115.GE11115@waste.org> References: <1183529972.6005.1.camel@localhost.localdomain> <20070704132025.GZ11115@waste.org> <1183599525.6005.55.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <1183599525.6005.55.camel@localhost.localdomain> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: Rusty Russell Cc: Andrew Morton , virtualization List-Id: virtualization@lists.linuxfoundation.org On Thu, Jul 05, 2007 at 11:38:45AM +1000, Rusty Russell wrote: > On Wed, 2007-07-04 at 08:20 -0500, Matt Mackall wrote: > > On Wed, Jul 04, 2007 at 04:19:32PM +1000, Rusty Russell wrote: > > > Lguest currently requires a TSC, which breaks older machines and Matt > > > Mackall who boots the host with "notsc". > > > > I do? I temporarily had a "notsc" arg in my lguest launcher script, > > but removing it made no difference. I do* boot the host with NO_HZ though. > > NO_HZ should be OK, but last we spoke, "notsc" in the host caused > lguest_data.tsc_khz to be zero => divide by zero errors (the previous > fixes should sort out the other TSC issues). I did indeed have a zero tsc_khz, and my system does mark TSC unstable (falling back to acpi-pm). But I've never once booted the host kernel on this laptop with "notsc". I've experimented with booting a guest with notsc to see if it would help. As a further datapoint, rc6-mm1 host and guest works. > Anyway, if the host decides not to use the TSC, the guest shouldn't use > it, which is the basis of this patch... Sure. -- Mathematics is the supreme nostalgia of our time.