From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] kvm: fix cpuid eax Date: Tue, 01 May 2012 15:53:24 +0300 Message-ID: <4F9FDCC4.3030302@redhat.com> References: <20120430143902.GA10181@redhat.com> <4F9EF7FA.3060007@codemonkey.ws> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "Michael S. Tsirkin" , Marcelo Tosatti , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, davej@redhat.com To: Anthony Liguori Return-path: Received: from mx1.redhat.com ([209.132.183.28]:12835 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754764Ab2EAMxm (ORCPT ); Tue, 1 May 2012 08:53:42 -0400 In-Reply-To: <4F9EF7FA.3060007@codemonkey.ws> Sender: kvm-owner@vger.kernel.org List-ID: On 04/30/2012 11:37 PM, Anthony Liguori wrote: > On 04/30/2012 09:39 AM, Michael S. Tsirkin wrote: >> cpuid eax should return the max leaf so that >> guests can find out the valid range. >> This matches Xen et al. > > What KVM does here predates Xen and Hyper-V. > > This is an ABI breaker. First, I don't think we ever documented eax, so nothing can rely on it. Second, this isn't guest visible, it's just part of KVM_GET_SUPPORTED_CPUID (used by qemu's -cpu host, but doesn't affect qemu stable cpus). -- error compiling committee.c: too many arguments to function