From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sheng Yang Subject: Re: kvm: emulation failure Date: Mon, 22 Jun 2009 13:12:36 +0800 Message-ID: <200906221312.36795.sheng@linux.intel.com> References: <1245439420.6262.349.camel@localhost> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-15" Content-Transfer-Encoding: 7bit Cc: Anthony Liguori To: kvm@vger.kernel.org, linuxram@us.ibm.com Return-path: Received: from mga05.intel.com ([192.55.52.89]:61458 "EHLO fmsmga101.fm.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751327AbZFVFNK (ORCPT ); Mon, 22 Jun 2009 01:13:10 -0400 In-Reply-To: <1245439420.6262.349.camel@localhost> Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-ID: On Saturday 20 June 2009 03:23:40 Ram Pai wrote: > I see this problem with a x86 sles10 guest running on x86_64 intel host. > If the guest is reset abruptly and rebooted, some where > before grub sequence it hangs and the following message is seen in the > logs > > emulation failed (pagetable) rip 7ed5 66 60 ac 20. > > I located this instruction sequence in isolinux.bin on the iso ;if that > is relevant. > > > I did some analysis and find that there is an ept violation, which is > handled and then the next instruction '66 60' is attempted to decode > and emulate. But decode fails. kvm continues loops in the kernel > in __vcpu_run(). > > the code path is > > kvm_run() -> __vcpu_run() -> vcpu_enter_guest() -> kvm_handle_exit() -> > handle_ept_violation() -> kvm_mmu_page_fault() -> emulate_instruction() -> > x86_decode_insn() > Hi Ram Seems KVM failed to emulate a unknown instruction. 00000000 6660 pushad 00000002 AC lodsb And PUSHAD have not implemented in x86_emulate.c. But I am a little curious about why this code path was only triggered when reset. Maybe other issue exists. -- regards Yang, Sheng > > Any insights here on how to fix the problem is appreciated. And if a fix > already exists even better :) > > thanks, > RP > > -- > To unsubscribe from this list: send the line "unsubscribe kvm" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html