Now: Understanding Muen and base_hw kernel from docs, [Earlier] Re: Problem with make run/demo ....

[Shahbaz khan]

Thank you for your detailed and caring reply. I believe i got lost with the
build think diagram. The diagram is not purely a runtime diagram.

On Saturday, April 15, 2017, Norman Feske <norman.feske at ...1...>
wrote:

> Hello Shahbaz,
>
> >     I've been wondering, is there any reason not to use
> >     base-hw_x86_64_muen on regular hardware? It seems to work fine in
> >     Qemu, and
> >
> >
> > Release notes mention Thinkpad X201.Muen website makes me cautious but
> > if Qemu works then we are good for a start. Have your tried virtualbox?
>
> Muen relies on hardware-assisted virtualization (Intel-VT). For running
> it inside a virtual machine, the virtual machine must support nested
> virtualization. As far as I known, VirtualBox does not support that.
>
>
Good to know in time.


> > Well anything is easily possible with micro-kernel architecture in
> > concept but I was curious whether we run base_hw kernel that is muen
> > according to mainline repo's files.
>
> Let me try to clarify the roles of Muen, base-hw, and VirtualBox:
>
> * Muen is a static separation kernel that uses VT to turn one physical
>   machine into a statically configured number of "partitions" (aka
>   "subjects"). Each partition is similar to a virtual machine. So
>   partitions are rather coarse-grained and static. Muen runs in
>   VT-root mode whereas the partitions run on VT-non-root mode.
>
> * Base-HW is a microkernel that uses virtual memory (like page tables)
>   to establish the notion of sandboxed user-level components on top
>   of it. Those components are light-weight and dynamic. To draw an
>   analogy, if you imaging a Muen subject to be a virtual machine, you
>   may think of a Genode component as an OS process. The base-hw kernel
>   runs in kernel mode whereas the components run in user mode.
>
> * VirtualBox is both a low-level piece of software that closely
>   interacts with virtualization hardware, but also a sophisticated
>   user-level application that relies on broad higher-level OS
>   infrastructure. E.g., it expects the underlying operating system
>   to provide host device drivers (for graphics, networking, input,
>   audio, block devices, USB), it needs to accesses virtual disk images
>   via an OS-provided file system, it spawns multiple threads, etc.

The role of Genode (including base-hw) in this scenario is to bridge the
> gap between the rather spartan environment of a Muen subject and the
> high functional requirements of the VirtualBox application. So you may
> see Genode as a mere runtime environment for VirtualBox. In principle,
> this gap could be filled by another software stack like a Linux-based
> OS. But as I stated above, in addition to being a complex application,
> VirtualBox closely interacts with the virtualization hardware. On Muen,
> this interaction naturally has to go through the Muen SK. By using
> Genode as runtime for VirtualBox, Muen is able to leverage Genode's
> existing solution of the interaction of VirtualBox with a
> microkernel-based virtualization mechanism.


Similar to karma-vmm, fiasco.oc and l4linux.


>
> >         I got a bit acquainted with the release notes but I still find
> >         it difficult to comprehend what really base-hw means when we say
> >         "Genode base -hw" on Muen SK.
>
> Conceptually, a Muen partition is a hardware platform, similar to a
> board. Like on any board, you can run software directly (in supervisor
> mode). But for running a complex software stack, or more than one
> application, one has to use an operating system (OS). Genode/base-hw
> plays this role.


Simply put a build time think. Base-hw kernel means muen sk for genode
runtime.


>
> >         I am having some build issues (I do get an image.elf but build
> >         does not complete) and have yet not looked into earlier commits
> >         and branches so I would appreciate if you can let me know what
> >         actually runs over Muen SK in Genode base-hw kernel VM. Does it
> >         mean we run another kernel like nova between Muen and virtualbox.
>
> Base-HW is unrelated to NOVA or any of the other kernels. It is a
> microkernel specifically developed for and tightly integrated with
> Genode. Think of it as an optional back end of Genode to run
> Genode-based systems directly on hardware (or virtual hardware like a
> Muen partition) without a third-party kernel.


By the way it seems fiasco.oc is not being maintained. Is something better
available, which supports both micrkernel based runtime and
virtualization..?

Regards,
Shahbaz


-- 
Shahbaz Khan
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