L4Re multiple Linux instances communication

Adam Lackorzynski adam at os.inf.tu-dresden.de
Tue Sep 21 23:06:18 CEST 2010

Hi Michael,

On Mon Sep 20, 2010 at 14:38:28 +0200, Michael Weiß wrote:
> I compiled the l4linux kernel with the l4shm driver,
> and tried to follow your advise to create a namespace
> and give it to the two l4linux instances.
> However, I have difficulties to understand the whole lua
> stuff.
> So I might did the namespace creation wrong,
> because the l4shm driver is complaining about that it cannot
> find the namespace:
> First l4linux instance with create:
> shmns: Requesting, role Creator, Shmsize 1024 Kbytes
> shmns: Failed to establish communication
> Second l4linux instance:
> shmns: Requesting, role User, Shmsize 1024 kbytes
> l4linux1| shm: did not find 'shmns' namespace
> I tired to create the namespace like that:
> shmns = L4.default_loader:create_namespace("shmns");
> Could you tell me, how to create the L4Re namespace right
> and maybe needed capability settings.

That's already good but probably missing to give the shmns cap more
rights. Do it like this for the Linux launch:
   ...:start({ caps = { shmns = shmns:mode("rw"), ...

So the ':mode("rw")' is important here so that the Linuxes can put
something in the namespaces. Used without 'mode' they are defaulting to
just be 'read-only'.

Unfortunately there's some rough spot in the shm-lib currently so that
the synchronization between the two parties doesn't work. I'm working on
a fix though...

Adam                 adam at os.inf.tu-dresden.de
  Lackorzynski         http://os.inf.tu-dresden.de/~adam/

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