WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

Re: [Xen-devel] one question to p2m table entry type

To: "Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx>, Tim Deegan <Tim.Deegan@xxxxxxxxxxxxx>
Subject: Re: [Xen-devel] one question to p2m table entry type
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Wed, 5 May 2010 10:21:56 +0100
Cc: "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Delivery-date: Wed, 05 May 2010 02:23:07 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <789F9655DD1B8F43B48D77C5D30659731E417BBD@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Thread-index: AcrsK3XNTTumvkQmSu6+Zwjy54vFgwACPIl1
Thread-topic: [Xen-devel] one question to p2m table entry type
User-agent: Microsoft-Entourage/12.24.0.100205
I think you're right, and this was probably too subtle to pick up in the
initial phase of code cleanup when non-pae support was removed. I think
Tim's away for a week or two now so you may not get a definitive response
for a little while.

 -- Keir

On 05/05/2010 09:17, "Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx> wrote:

> Tim/Keir, I noticed that when translatiing p2m table type and p2m pte entry
> flags, there are difference handling for x86_64 and x32 like:
> 
> in p2m_type_to_flags:
> #ifdef __x86_64__
>     flags = (unsigned long)(t & 0x3fff) << 9;
> #else
>     flags = (t & 0x7UL) << 9;
> #endif
> 
> in p2m_flags_to_type:
>     /* Type is stored in the "available" bits */
> #ifdef __x86_64__
>     return (flags >> 9) & 0x3fff;
> #else
>     return (flags >> 9) & 0x7;
> 
> But since we don't support pure 32 bit xen hypervisor any more, and for 32
> PAE, we are sure have enough bit to keep these flags, why do we need these
> special handling? Are there any special reason for it?
> 
> Thanks
> --jyh
> 
> _______________________________________________
> Xen-devel mailing list
> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel