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

[Jean-Yves Migeon <jeanyves.migeon%free.fr@localhost>]

On 12.07.2010 18:03, Antti Kantee wrote:
> On Mon Jul 12 2010 at 17:36:10 +0200, Jean-Yves Migeon wrote:
>> - 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".

Huh? On what ground?

My initial step would be to have a block backend driver running in
userland, so I can make it run as a standalone server. Purpose is to
help diagnosing errors in a more graceful manner. I lost tremendous time
tracking a DoS issue between frontend and backend drivers for domain
migration, for one stupid reason: the backend caused a DoS to the rest
of the *dom0* kernel, without even being capable of breaking into ddb...

>> - 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?

As you say below: it needs a bus_space implementation.

> 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.

-- 
Jean-Yves Migeon
jeanyves.migeon%free.fr@localhost