Re: [Xen-devel] [new PV device]

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Mon, Apr 14, 2014 at 05:45:00PM +0200, Vincenzo Maffione wrote:
> Hi,
>    I would like to design a new paravirtual device for Xen PV guests
> (under Linux),
> for research purposes.
> This device should be a "simplification" of netfront/netback in that
> the interface
> with the domU/dom0 O.S. is not the normal TCP/IP stack, but something way
> simpler (however, this is not so important w.r.t. my question).
> 
> Looking at the netback code
>      linux:drivers/net/xen-netback/xenbus.c
> I've run into some "hotplug scripts" support code.
> The netfront code, on the other hand, has no hotplug-related code.
> 
> I don't really understand what is the purpose of this hotplug support
> (Is it something
> related to the vif-* scripts?), but I'm wondering whether I can get

Yes, you're right.

> rid of this code for my
> "simplified" device.
> 

Of course you can, if you don't need user space event handling or don't
mind doing some tedious configurations by hand.

> It would be enough for me to be able to do the following:
>   1) manually load my backend driver kernel module in Dom0
>   2) manually load my frontend driver kernel module in DomU
>   3) being able to use my device (think as I have userspace access to
> the device through a character device).
> I don't want/need any configuration scripts in Dom0 nor DomU (no sw
> bridges or routing
> tables to configure).  Just plain simple Dom0 <==> DomU buffer exchange.
> 
> Is it possibile to achieve this without any "hotplug code"? Or do I need some

Yes, that's possible.

You can have a look at other Xen PV drivers as well. Probably Xen PV
framebuffer can be a good starting point.

Xen wiki also has some general information on PV driver.

Wei.

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
http://lists.xen.org/xen-devel