Question about memory management in L4 Fiasco O.C + L4re

Adam Lackorzynski adam at os.inf.tu-dresden.de
Mon Jul 20 23:30:50 CEST 2015


Hi,

On Mon Jul 20, 2015 at 16:36:52 +0200, Mahdi Aichouch wrote:
> If I correctly understood, and If we suppose that an L4Linux instance
> is started for example with this command line options:
> ... earlyprintk=1 em=64M ...
> 
> This means that a 64MB of physical memory region composed of a set of
> contiguous physical frames is allocated to L4Linux, right?

Yes.

> L4Linux will use a part of this 64MB of physical memrory for its own kernel
> execution, and
> the rest of physical memory space will be used by L4Linux to load
> user-level programs
> and allocate physical memory for them, right?

Yes.

> If a user-level program on top of L4Linux generates a page-fault.
> Are the L4 Fiasco kernel and L4re involved in the execution flow to handle
> the page-fault?

Only Fiasco is involved because the host kernel will get the page fault
exception from the CPU. Fiasco will then invoke the L4Linux kernel with
appropriate info on the page fault to let L4Linux handle it. L4Re is not
involved here.




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



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