Re: CVS commit: src/tests/net/icmp

[Antti Kantee <pooka%cs.hut.fi@localhost>]

On Mon Jul 12 2010 at 17:36:10 +0200, Jean-Yves Migeon wrote:
> On 12.07.2010 16:41, Antti Kantee wrote:
> > It's not the same thing.  Correct me if I misunderstood, but I thought
> > you want to port/adjust/whatever rumpuser to the xen hypercall interace.
> > Since the xen hypervisor interface, as opposed to a posix process
> > environment, is designed for hosting an OS, you can do lowlevel ops
> > as you'd expect to do them instead of having to think about high-level
> > semantic meaning.
> 
> My goal: take rumpuser, and see how it could be used in microkernel-like
> environment. Xen is my target (personal/free time work, just to make an
> initial approach to rumpuser), but other API might be possible (this
> part depends on external factors encountered at $DAYJOB).
> 
> Though there are some points I am still unsure with, some of them being:
> 
> - routing (the same way you pass message back and forth with puffs/pud);
> for Xen, this cannot be solved through the hypervisor API, you have to
> pull in Xen ring I/Os, and Xenstore, which acts as key:value storage
> facility so that domains can share information ("if you want to issue
> block requests for xbd0, contact domain 'foo'").

Just to make sure everyone (else) understands: forget puffs/pud.
They are *completely* orthogonal to rump -- one does not require nor
imply the other.

Now, why do you expect this to not work like it does with the current
style of dom0? ... aah, currently everything just goes to dom0, and
now you'd need to pick which server can actually service your request?
While I'm not familiar with the Xen ecosystem (buzzword!!), from the
technical perspective it looks like this falls under "SMOP".

> - drivers (how could it work with passthrough, what is attainable/what
> is not)

"passthrough"?  You mean exporting hardware directly to guests?  How would
it be different?

Hmm, I assume you'd want to mostly run hardware drivers for dom0.
You might have to write a bus_space implementation for rump (some others
have been interested in this as well).  The good news is that the x86
ports are clear of the macro madness (thanks ad) and I assume you're
mostly interested in them.  I don't even know how Xen deals with DMA.