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 (v2) Date: Mon, 06 Dec 2010 10:28:54 +0200 Message-ID: <4CFC9EC6.3010108@redhat.com> References: <1291298357-5695-1-git-send-email-aliguori@us.ibm.com> <20101202173733.GA26342@amt.cnet> <4CF7EE63.40209@codemonkey.ws> <20101202201223.GA31316@amt.cnet> <4CF806E7.1090404@codemonkey.ws> <4CF8BA34.1000508@redhat.com> <4CF9730C.7040904@codemonkey.ws> <4CF9F83C.5040807@redhat.com> <4CFA425D.3010100@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , kvm@vger.kernel.org, Chris Wright , Srivatsa Vaddagiri To: Anthony Liguori Return-path: Received: from mx1.redhat.com ([209.132.183.28]:45134 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751035Ab0LFI3V (ORCPT ); Mon, 6 Dec 2010 03:29:21 -0500 In-Reply-To: <4CFA425D.3010100@codemonkey.ws> Sender: kvm-owner@vger.kernel.org List-ID: On 12/04/2010 03:30 PM, Anthony Liguori wrote: > On 12/04/2010 02:13 AM, Avi Kivity wrote: >> On 12/04/2010 12:45 AM, Anthony Liguori wrote: >>>> hlt exiting doesn't leave vcpu in the halted state (since hlt has >>>> not been executed). So currently we never see a vcpu in halted state. >>> >>> >>> Right, you mean the guest activity state being halt. >>> >>> My understanding is that it just needs to be cleared on exception >>> injection. Would could clear it at every vmentry but that would >>> introduce a vmcs_read() to the fast path which is undesirable. >> >> Also need to skip the hlt instruction (by calling the emulator for >> example). > > I wasn't sure about this. Don't you want EIP to point to the > beginning of the instruction such that the exception will cause the > instruction to restart? An interrupt causes the HLT to complete execution. APF completion counts as an interrupt in this case. -- error compiling committee.c: too many arguments to function