From mboxrd@z Thu Jan  1 00:00:00 1970
From: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Subject: Re: [PATCH v2 7/9] KVM: MMU: Optimize is_last_gpte()
Date: Tue, 18 Sep 2012 15:36:07 +0800
Message-ID: <50582467.9080706@linux.vnet.ibm.com>
References: <1347797235-20732-1-git-send-email-avi@redhat.com> <1347797235-20732-8-git-send-email-avi@redhat.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Cc: Marcelo Tosatti <mtosatti@redhat.com>, kvm@vger.kernel.org,
	Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
To: Avi Kivity <avi@redhat.com>
Return-path: <kvm-owner@vger.kernel.org>
Received: from e23smtp08.au.ibm.com ([202.81.31.141]:37495 "EHLO
	e23smtp08.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S932082Ab2IRHgR (ORCPT <rfc822;kvm@vger.kernel.org>);
	Tue, 18 Sep 2012 03:36:17 -0400
Received: from /spool/local
	by e23smtp08.au.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted
	for <kvm@vger.kernel.org> from <xiaoguangrong@linux.vnet.ibm.com>;
	Tue, 18 Sep 2012 17:35:42 +1000
Received: from d23av03.au.ibm.com (d23av03.au.ibm.com [9.190.234.97])
	by d23relay04.au.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id q8I7QtNx28770510
	for <kvm@vger.kernel.org>; Tue, 18 Sep 2012 17:26:56 +1000
Received: from d23av03.au.ibm.com (loopback [127.0.0.1])
	by d23av03.au.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id q8I7a9IP006386
	for <kvm@vger.kernel.org>; Tue, 18 Sep 2012 17:36:10 +1000
In-Reply-To: <1347797235-20732-8-git-send-email-avi@redhat.com>
Sender: kvm-owner@vger.kernel.org
List-ID: <kvm.vger.kernel.org>

On 09/16/2012 08:07 PM, Avi Kivity wrote:
> Instead of branchy code depending on level, gpte.ps, and mmu configuration,
> prepare everything in a bitmap during mode changes and look it up during
> runtime.
> 

Avi,

Can we introduce ignore_bits_mask[] (like rsvd_bits_mask), if pse is not supported,
we can set PTE_PSE in this ignore_bits_mask, then the function can be simplified to

	return (level == 1) || gpte & ~vcpu->ignore_bits_mask[level] & PTE_PSE

I think it is more readable.