From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keir Fraser <keir@xensource.com>
Subject: Re: [PATCH 0/3][IA64] Accelerate IDE PIO on HVM/IA64
Date: Tue, 27 Feb 2007 10:56:16 +0000
Message-ID: <C209BED0.A365%keir@xensource.com>
References: <200702270850.l1R8oeK3019985@bx604.sky.yk.fujitsu.co.jp>
Mime-Version: 1.0
Content-Type: text/plain;
	charset="US-ASCII"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xensource.com>
In-Reply-To: <200702270850.l1R8oeK3019985@bx604.sky.yk.fujitsu.co.jp>
List-Unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xensource.com>
List-Help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-Subscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
Sender: xen-devel-bounces@lists.xensource.com
Errors-To: xen-devel-bounces@lists.xensource.com
To: Kouya SHIMURA <kouya@jp.fujitsu.com>, Alex Williamson <alex.williamson@hp.com>
Cc: xen-devel@lists.xensource.com, xen-ia64-devel@lists.xensource.com
List-Id: xen-devel@lists.xenproject.org




On 27/2/07 09:34, "Kouya SHIMURA" <kouya@jp.fujitsu.com> wrote:

> The basic idea is to add a buffering mechanism in a hypervisor.
> I know this approach is not sophisticated. But there is no other
> good way in IA64 which has no string instructions like x86's.
> 
> This patchset is indispensable to support windows/ia64 on HVM
> since installing windows and crash dumping is terribly slow.

Can you explain how this new code works? As I understand it the problem is
that each PIO instruction decoded by Xen and propagated to qemu only
transfers a single word of data. How does this new buffering mechanism work
around this?

 -- Keir