From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [RFC] KVM: x86: emulate movdqa Date: Mon, 09 Jan 2012 12:02:22 +0200 Message-ID: <4F0ABB2E.10200@redhat.com> References: <1325932011-2728-1-git-send-email-stefanha@linux.vnet.ibm.com> <4F0970DB.6060405@redhat.com> <4F09C720.3090006@redhat.com> <20120109175223.620d0d5a95be6f0fb7850bf9@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Stefan Hajnoczi , Stefan Hajnoczi , kvm@vger.kernel.org, Takuya Yoshikawa To: Takuya Yoshikawa Return-path: Received: from mx1.redhat.com ([209.132.183.28]:55737 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751599Ab2AIKC3 (ORCPT ); Mon, 9 Jan 2012 05:02:29 -0500 In-Reply-To: <20120109175223.620d0d5a95be6f0fb7850bf9@gmail.com> Sender: kvm-owner@vger.kernel.org List-ID: On 01/09/2012 10:52 AM, Takuya Yoshikawa wrote: > Avi Kivity wrote: > > > > Can you think of a case where we need to perform alignment checking in > > > the emulator? > > > > The case that x86/svm.c is checking for is a security issue. > > > > Guests don't normally turn eflags.AC on, so I don't expect issues > > there. I also don't see issues with SSE alignment, especially as AVX > > removes it (for VEX encoded instructions). However, it's good to stick > > to the spec, there are always surprise issues when you don't. > > > > Isn't it make sense to add Documentation/virtual/kvm/emulator.txt at some > point in the future? > > In some cases it is difficult to know the underlying assumptions. Sure. > Explanations about the emulator specific macros may also be helpful. Those might be better as code comments, where those macros are defined. -- error compiling committee.c: too many arguments to function