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

[Xen-devel] PV drivers for HVM guests

To: <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] PV drivers for HVM guests
From: "Ky Srinivasan" <ksrinivasan@xxxxxxxxxx>
Date: Tue, 03 Oct 2006 16:31:12 -0400
Delivery-date: Tue, 03 Oct 2006 13:31:48 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
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/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/cgi-bin/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
I am trying to build PV drivers for SLES9 HVM guests. SLES 9 is based on the 
2.6.5 kernel. Since the PV driver code is really designed for the latest kernel 
release, I have had many issues/problems in building the PV drivers for older 
Linux OS targets - I have only been looking at the issues with 2.6.5 kernel 
base and I suspect the problem will be even worse if one were to look at older 
Linux kernels. This is unfortunate since PV drivers are so critical for HVM 
guests and there is considerable interest in supporting legacy Linux 
environments as HVM guests. The problems I have had to deal with can be broadly 
classified into:

a) Compiler related issues
b) Missing functionality in the legacy kernel - this includes features as well 
as changed data structures
c) Implementation differences of a given feature

These differences can be dealt with in a couple of different ways:
1) Modify the code in the PV drivers under appropriate compilation switches to 
deal with the differences in the base kernels.
2)  Introduce  a compatibility component that bridges the gap between the 
current PV code and a given Linux target and leave much of the PV driver  code 
untouched.

I have implemented both these schemes for the sles9 kernel and would like to 
get your input on your preference. I personally like option 2. Going forward, 
the evolution of PV drivers needs to be constrained by the required support for 
legacy Linux environments. 

Regards,

K. Y. Srinivasan 





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