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] PV drivers for HVM guests

To: Ky Srinivasan <ksrinivasan@xxxxxxxxxx>
Subject: Re: [Xen-devel] PV drivers for HVM guests
From: "Andrew D. Ball" <aball@xxxxxxxxxx>
Date: Tue, 03 Oct 2006 18:19:55 -0400
Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
Delivery-date: Tue, 03 Oct 2006 15:18:03 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxx
In-reply-to: <45229025.E57C.0030.0@xxxxxxxxxx>
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>
Organization: IBM
References: <45229025.E57C.0030.0@xxxxxxxxxx>
Reply-to: aball@xxxxxxxxxx
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
Interesting!  Ideally, there would be better performance in the base HVM
device model.  I think I know of some people that are working hard on
that.

I'm curious to see what you've done for (1) and (2).

Peace.
Andrew

On Tue, 2006-10-03 at 16:31 -0400, Ky Srinivasan wrote:
> 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


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