From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH RFC] KVM: inject #UD if instruction emulation fails while vcpu is in cpl==3 Date: Thu, 06 May 2010 15:33:12 +0300 Message-ID: <4BE2B708.2020705@redhat.com> References: <20100429115847.GW10044@redhat.com> <4BE288CE.5050801@redhat.com> <20100506100645.GB24787@redhat.com> <4BE2964A.1090906@redhat.com> <20100506122553.GC24787@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: mtosatti@redhat.com, kvm@vger.kernel.org To: Gleb Natapov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:37997 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751777Ab0EFMdO (ORCPT ); Thu, 6 May 2010 08:33:14 -0400 Received: from int-mx08.intmail.prod.int.phx2.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.21]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id o46CXD0k028132 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Thu, 6 May 2010 08:33:13 -0400 Received: from cleopatra.tlv.redhat.com (cleopatra.tlv.redhat.com [10.35.255.11]) by int-mx08.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id o46CXClN022182 for ; Thu, 6 May 2010 08:33:13 -0400 In-Reply-To: <20100506122553.GC24787@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 05/06/2010 03:25 PM, Gleb Natapov wrote: > >> We can expect that from a developer or a user subscribed to kvm@. >> But what about some random user running virt-manager? >> >> > What virt-manager would do about such error? > Call up abrt. >> True. But the same problem exists with cpl>0 #UD. It may be a >> critical driver in userspace (say, video driver). >> >> Also need to think consider nested kernels (which are userspace for >> this purpose). >> > Ugh, we can check if vcpu is in nested mode. > And do what? Inject #UD to the guest? Or force some vmexit? >> How about default to unconditional #UD and report, and pause if >> requested (in userspace)? Usually emulation failures will be 100% >> reproducible, so the user can rerun their workload. >> >> > Didn't what to involve userspace in this, but it can be done of course. > Whenever we have to make a decision, we involve userspace. -- error compiling committee.c: too many arguments to function