From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] kvm-vmx: add module parameter to avoid trapping HLT instructions (v4) Date: Mon, 06 Dec 2010 15:43:56 +0200 Message-ID: <4CFCE89C.10904@redhat.com> References: <1291473801-23290-1-git-send-email-aliguori@us.ibm.com> <20101205165513.GC440@linux.vnet.ibm.com> <4CFCE4B6.1030705@redhat.com> <20101206133952.GE440@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Anthony Liguori , kvm@vger.kernel.org, Marcelo Tosatti , Chris Wright To: vatsa@linux.vnet.ibm.com Return-path: Received: from mx1.redhat.com ([209.132.183.28]:2180 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752399Ab0LFNoF (ORCPT ); Mon, 6 Dec 2010 08:44:05 -0500 In-Reply-To: <20101206133952.GE440@linux.vnet.ibm.com> Sender: kvm-owner@vger.kernel.org List-ID: On 12/06/2010 03:39 PM, Srivatsa Vaddagiri wrote: > > >Also, just curious how this would work for idle vcpus that use mwait rather > > >than hlt. > > > > We don't expose mwait to the guest (emulating mwait is very expensive). > > We seem to be queuing an exception upon mwait (EXIT_REASON_MWAIT_INSTRUCTION > being handled by a handle_invalid_op()). Does that kill the guest? It sends a #UD, which tells the guest mwait isn't supported. Usually the guest will fall on its sword at this point, but that's not mandated. -- error compiling committee.c: too many arguments to function