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] [PATCH] Fix build failure in 32 environment

To: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>, "Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx>
Subject: RE: [Xen-devel] [PATCH] Fix build failure in 32 environment
From: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
Date: Mon, 14 Dec 2009 08:52:50 -0800 (PST)
Cc: "Xu, Dongxiao" <dongxiao.xu@xxxxxxxxx>, xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Mon, 14 Dec 2009 08:53:20 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <C74C181E.4668%keir.fraser@xxxxxxxxxxxxx>
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
> > If I remember correctly, rdtscp is a valid instruction
> > in 32-bit mode so why are you disabling support for
> > 32-bit Xen?
> > 
> > Personally, I don't care if 32-bit Xen is supported,
> > but either we need to say it is supported or it is
> > not supported, not have new features randomly choose
> > to support it or not, especially features that have
> > impact on userland applications.
> 
> It can be supported for existign features but not all new ones. We can
> perhaps retire it all together after 4.0.

IMHO, this is not a new feature, this is an ABI incompatibility
issue. If rdtscp is a valid 32-bit instruction, IMHO it
should either work on both 32-bit Xen and 64-bit Xen or
neither.

Was this patch a quick hack to allow the code to compile
for 32-bit Xen or was it a reasoned decision to disallow
support on 32-bit Xen?

(And, in any case, if rdtscp is a "new feature", why was
the patch accepted post-freeze, especially when there
is still lively debate going on? ;-)

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