From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Olszewski Subject: Re: KVM Page Fault Question Date: Mon, 26 Apr 2010 01:42:58 -0400 Message-ID: <4BD527E2.6010305@csail.mit.edu> References: <4B9726A7.7000800@csail.mit.edu> <4B976AA8.9030904@redhat.com> <4B9833EE.1070705@csail.mit.edu> <4B989035.4050109@redhat.com> <4B9916DE.30209@csail.mit.edu> <4B9B5225.2050604@redhat.com> <4BA2BC2A.8090803@csail.mit.edu> <4BA33833.8060703@redhat.com> <4BB57596.6090109@csail.mit.edu> <4BB59117.2040903@redhat.com> <4BB614BC.9080608@csail.mit.edu> <4BB8C566.70807@redhat.com> <4BCFDE1C.7080209@csail.mit.edu> <4BCFF241.4080206@redhat.com> <4BD0DFBE.1090103@csail.mit.edu> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Avi Kivity Return-path: Received: from DMZ-MAILSEC-SCANNER-6.MIT.EDU ([18.7.68.35]:42002 "EHLO dmz-mailsec-scanner-6.mit.edu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752636Ab0DZFsG (ORCPT ); Mon, 26 Apr 2010 01:48:06 -0400 In-Reply-To: <4BD0DFBE.1090103@csail.mit.edu> Sender: kvm-owner@vger.kernel.org List-ID: Avi, > > I guess I only really care about intercepting ring 0 -> ring 3 > transitions in the guest. Is there an easier way of intercepting these? Never mind about this. I figured out a solution to my problem that didn't need to intercept these transitions. Unfortunately, now I have a new problem. I'm getting a segfault in gfn_to_rmap caused by gfn_to_memslot returning NULL. Would someone mind explaining this code to me? I don't really understand what it is doing. Also, does the current code assume that any guest page in any level can be shadowed more than once, or are only certain levels allowed to be shadowed multiple times? Thank you! Marek > > Marek > > > Avi Kivity wrote: >> On 04/22/2010 08:26 AM, Marek Olszewski wrote: >>> Under VMX without EPT, I do not seeing any VM Exits due to task >>> switches. Is there a way to enable these? I'm looking to intercept >>> the guest whenever it does a iret. >> >> See EXIT_REASON_TASK_SWITCH. However, that won't fire on any iret, >> only irets that generate task switches. You can ask for exits on >> irets by setting CPU_BASED_VIRTUAL_NMI_PENDING and >> GUEST_INTR_STATE_NMI, and looking for EXIT_REASON_NMI_WINDOW. >> > >