From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jan Kiszka Subject: Re: Unable to single-step in kvm, always results in a resume Date: Fri, 22 Jan 2010 16:06:24 +0100 Message-ID: <4B59BEF0.80407@siemens.com> References: <4B55C05D.6030408@xceedium.com> <4B55CBA8.6040306@siemens.com> <4B55CBFF.5030900@siemens.com> <4B566CB5.7080804@xceedium.com> <4B56D62D.3060106@siemens.com> <4B5922BE.7030002@xceedium.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: kvm To: Nicholas Amon Return-path: Received: from goliath.siemens.de ([192.35.17.28]:23534 "EHLO goliath.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752466Ab0AVPG2 (ORCPT ); Fri, 22 Jan 2010 10:06:28 -0500 In-Reply-To: <4B5922BE.7030002@xceedium.com> Sender: kvm-owner@vger.kernel.org List-ID: Nicholas Amon wrote: > So now I can step instruction but my breakpoints do not work. I have > verified that disabling kvm restores the breakpoint functionality. Any > suggestions? What kind of breakpoints, hardware-assisted or normal BPs? Are you trying to break into real-mode code (as stated below - BTW, top-postings should be avoided!) that happens to run on a non-brand-new Intel host? I never fully tested how well guest debugging works if KVM has to emulate instructions, and I wouldn't be surprised if there are "limitations". Jan > Jan Kiszka wrote: >> Hi Nicholas, >> >> please don't drop CCs on reply. >> >> Nicholas Amon wrote: >> >>> Hi Jan, >>> >>> Thanks for responding. Yes, I am able to step instruction when I >>> disable kvm w/ the no-kvm option. My host kernel is 64bit 2.6.27 and >>> the program that I am debugging is 32 bit but starts in real mode. But >>> the KVM module I am running is from kvm-88. Is there anyway I can check >>> the version definitively? >>> >> kvm modules issue a message when being loaded, check your kernel log. >> qemu-kvm gives you the version via -version. >> >> OK, the problems you see is likely related to the very old versions you >> use. Update to recent kvm-kmod (2.6.32 series) and qemu-kvm (0.12 >> series) and retry. >> >> Jan >> >> >>> Thanks, >>> >>> Nicholas >>> >>> Jan Kiszka wrote: >>> >>>> Jan Kiszka wrote: >>>> >>>> >>>>> Nicholas Amon wrote: >>>>> >>>>> >>>>>> Hi All, >>>>>> >>>>>> I am trying to single-step through my kernel using qemu and kvm. I have >>>>>> run qemu via: qemu-system-x86_64 -s -S -hda >>>>>> /home/nickamon/lab1/obj/kernel.img and also connected to the process >>>>>> using gdb. >>>>>> >>>>>> Problem is that whenever I try and step instruction, it seems to resume >>>>>> my kernel rather than allowing me to progress instruction by >>>>>> instruction. I have built the kvm snapshot from git and still no luck. >>>>>> Tried following the code for a few hours and have no luck. Any >>>>>> suggestions? >>>>>> >>>>>> >>>>> What's you host kernel or kvm-kmod version? >>>>> >>>>> >>>>> >>>> ...and does -no-kvm make any difference (except that it's much slower)? >>>> >>>> Jan >>>> >>>> >>>> -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux