From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jan Kiszka <jan.kiszka@siemens.com>
Subject: Re: Using EPT to map guest MMIO to host MMIO
Date: Fri, 05 Aug 2011 09:41:24 +0200
Message-ID: <4E3B9EA4.3070803@siemens.com>
References: <CAOzbF4esgHqsngYQu+UHpBCwaf=Zkpc6PuY-9U_FGdmy7=bDZA@mail.gmail.com>
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: 7bit
Cc: kvm@vger.kernel.org
To: Cyclonus J <cyclonusj@gmail.com>
Return-path: <kvm-owner@vger.kernel.org>
Received: from goliath.siemens.de ([192.35.17.28]:20414 "EHLO
	goliath.siemens.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1754923Ab1HEHl0 (ORCPT <rfc822;kvm@vger.kernel.org>);
	Fri, 5 Aug 2011 03:41:26 -0400
In-Reply-To: <CAOzbF4esgHqsngYQu+UHpBCwaf=Zkpc6PuY-9U_FGdmy7=bDZA@mail.gmail.com>
Sender: kvm-owner@vger.kernel.org
List-ID: <kvm.vger.kernel.org>

On 2011-08-05 09:20, Cyclonus J wrote:
> hi,
> 
> I am wondering if it is possible to map guest MMIO to host MMIO, the
> purpose is to reduce VM_EXIT as the page tables will be setup before
> MMIO accessing from guest. Here is what I have in mind:

This is already the case if you pass through devices AND aligment&size
of the MMIO resource allows this.

What MMIOs do you see that are not mapped 1:1? For what kind of devices?

Jan

-- 
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux