From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH] KVM: x86: Save bits by merging Mmx/Sse/Avx bits Date: Thu, 06 Nov 2014 15:10:17 +0100 Message-ID: <545B8149.2050808@redhat.com> References: <1415265301-16746-1-git-send-email-namit@cs.technion.ac.il> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Nadav Amit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:39055 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750915AbaKFOK2 (ORCPT ); Thu, 6 Nov 2014 09:10:28 -0500 In-Reply-To: <1415265301-16746-1-git-send-email-namit@cs.technion.ac.il> Sender: kvm-owner@vger.kernel.org List-ID: On 06/11/2014 10:15, Nadav Amit wrote: > As we run out of bits in the KVM emulator instruction flags, we can merge > together the Mmx/Sse/Avx bits. These bits are mutual exclusive (i.e., each > instruction is either MMX, SSE, AVX, or none), so we can save one bit in the > flags by merging them. Do we need the Avx bit at all? Currently it is a dup of Unaligned, and I think we can just reuse Unaligned. If we see VEX, we just do "ctxt->d |= Unaligned". AVX instructions are just tweaks of the operand length and the alignment restrictions of SSE instructions, there is nothing really special about them. Paolo