RE: Bare metal driver for PV ethernet

[Paul Leiber <paul@xxxxxxxxxxxxxxxx>]

Am 11. Februar 2025 23:33:43 MEZ schrieb Klaus Darilion <klaus.darilion@xxxxxx>:
>> -----Original Message-----
>> From: Xen-users <xen-users-bounces@xxxxxxxxxxxxxxxxxxxx> On Behalf Of Paul
>> Leiber
>> Sent: Tuesday, February 11, 2025 9:40 PM
>> To: xen-users@xxxxxxxxxxxxxxxxxxxx
>> Subject: Re: Bare metal driver for PV ethernet
>> 
>> Am 04.02.2025 um 16:38 schrieb Carlos Domínguez Sánchez:
>> > We have been working with Xen and we successfully use the PV ethernet
>> > interface from Linux guests. We would like to follow the same approach
>> > with bare metal guests, but we did not find the appropriate driver for
>> > the virtual ethernet. Does anyone face a similar problem? Do you have
>> > any suggestion?
>> 
>> I don't have an answer to your question, I am afraid, but rather a
>> question myself. I apologize if my question is stupid. I know what a
>> bare metal server is, but I am not aware of the concept of a "bare metal
>> guest", so what does it mean? I found a document which describes how to
>> install a VM on a bare metal system [1], and something related to a
>> hypervisor called bao [2] but I am still unsure what the concept means.
>
>I think the term "bare metal guest" refers to a XEN guest which does not run a 
>complete operating system, but only a single application, as described for 
>example here:
>https://github.com/dornerworks/xzd_baremetal/blob/master/docs/index.md
>
>regards
>Klaus

Thanks for the explanation.

Based on my (limited) understanding, the key section in the link provided by 
you is:

"Paravirtualized Devices - Dom0 provides a front-end for some devices. To talk 
to these, a front-end needs to be implemented in the bare metal. This requires 
support for the XenStore, event channels, shared memory, and all of the related 
Hypercalls, which are currently not implemented in the XZD Bare Metal 
container."

I think there is a mistake in that section, it should be "Dom0 provides a 
back-end for some devices."

There is a section in the linux kernel sources called xenfront which provides 
the PV network functionality for linux guests by connecting to the backend 
("xenback"). I assume that you need to implement something similar to xenfront 
for your bare metal guest.

Best regards,

Paul