From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [PATCH v2] KVM: VMX: Update instruction length on intercepted BP Date: Wed, 17 Feb 2010 13:16:41 +0200 Message-ID: <20100217111641.GS2995@redhat.com> References: <4B795FD0.4060505@siemens.com> <20100216073352.GV2995@redhat.com> <4B7A51D4.1040701@web.de> <20100216082455.GY2995@redhat.com> <4B7A612A.4010603@siemens.com> <20100217104304.GP2995@redhat.com> <4B7BCF59.40402@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Jan Kiszka , Marcelo Tosatti , kvm To: Avi Kivity Return-path: Received: from mx1.redhat.com ([209.132.183.28]:54972 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752223Ab0BQLQt (ORCPT ); Wed, 17 Feb 2010 06:16:49 -0500 Content-Disposition: inline In-Reply-To: <4B7BCF59.40402@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Wed, Feb 17, 2010 at 01:13:29PM +0200, Avi Kivity wrote: > On 02/17/2010 12:43 PM, Gleb Natapov wrote: > >>And, again: This is an _existing_ user space ABI. We could only provide > >>an alternative, but we have to maintain what is there at least for some > >>longer grace period. > >> > >But it was always broken for SVM and was broken for VMX for a year and > >nobody noticed, so may be instead of reintroducing old interface we should > >do it right this time? > > We need to fix the existing interface first, and then think long and > hard if we want yet another interface, since we're likely to screw > it up as well. > > The more interfaces we introduce, the harder maintenance becomes. > We are in a sad state if we cannot improve interface. The current one outsource part of CPU functionality into userspace. This should be a big no-no. -- Gleb.