From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 4/4] KVM: x86: Add VCPU substate for NMI states Date: Sun, 25 Oct 2009 15:11:36 +0200 Message-ID: <4AE44E88.4000603@redhat.com> References: <20091013160647.27006.58598.stgit@mchn012c.ww002.siemens.net> <20091013160648.27006.29041.stgit@mchn012c.ww002.siemens.net> <4AD6D8B6.3050003@redhat.com> <4AD6E9E1.1040704@siemens.com> <4AD6EB63.9030306@redhat.com> <4AD7070D.7070108@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , "kvm@vger.kernel.org" To: Jan Kiszka Return-path: Received: from mx1.redhat.com ([209.132.183.28]:11908 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753511AbZJYNLf (ORCPT ); Sun, 25 Oct 2009 09:11:35 -0400 In-Reply-To: <4AD7070D.7070108@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: On 10/15/2009 01:27 PM, Jan Kiszka wrote: > >> Perhaps it makes sense to query about individual states, including >> existing ones? That will allow us to deprecate and then phase out >> broken states. It's probably not worth it. >> > You may do this already with the given design: Set up a VCPU, then issue > KVM_GET_VCPU_STATE on the substate in question. You will either get an > error code or 0 if the substate is supported. At least no additional > kernel code required. > No, if some code requires a feature, we don't want to set up a guest and a vcpu and issue dummy commands in order to find out if we can actually run that code. Feature discovery needs to be a 'system ioctl' in the words of Documentation/kvm/api.txt. -- error compiling committee.c: too many arguments to function