On 14.12.19 10:51, Mani Sadhasivam wrote:
>
>
> On Fri, 6 Dec, 2019, 1:39 PM Jan Kiszka, <[email protected]
> <mailto:[email protected]>> wrote:
>
>     On 05.12.19 20:32, Mani Sadhasivam wrote:
>     > Hi Jan,
>     >
>     > On Thu, Dec 5, 2019 at 1:38 PM Jan Kiszka <[email protected]
>     <mailto:[email protected]>
>     > <mailto:[email protected] <mailto:[email protected]>>>
>     wrote:
>     >
>     >     [re-adding the mailing list]
>     >
>     >     On 05.12.19 09:07, Jan Kiszka wrote:
>     >     > On 05.12.19 08:49, Mani Sadhasivam wrote:
>     >     >>
>     >     >>
>     >     >> On Thu, Dec 5, 2019 at 1:09 PM Jan Kiszka
>     <[email protected] <mailto:[email protected]>
>     >     <mailto:[email protected] <mailto:[email protected]>>
>     >     >> <mailto:[email protected]
>     <mailto:[email protected]> <mailto:[email protected]
>     <mailto:[email protected]>>>>
>     >     wrote:
>     >     >>
>     >     >>     On 05.12.19 08:14, Mani Sadhasivam wrote:
>     >     >>     > Hi Jan,
>     >     >>     >
>     >     >>     > On Thu, Dec 5, 2019 at 12:36 PM Jan Kiszka
>     >     <[email protected] <mailto:[email protected]>
>     <mailto:[email protected] <mailto:[email protected]>>
>     >     >>     <mailto:[email protected]
>     <mailto:[email protected]> <mailto:[email protected]
>     <mailto:[email protected]>>>
>     >     >>     > <mailto:[email protected]
>     <mailto:[email protected]>
>     >     <mailto:[email protected]
>     <mailto:[email protected]>> <mailto:[email protected]
>     <mailto:[email protected]>
>     >     <mailto:[email protected] <mailto:[email protected]>>>>>
>     >     >>     wrote:
>     >     >>     >
>     >     >>     >     On 02.12.19 19:43, Manivannan Sadhasivam wrote:
>     >     >>     >     > Hello,
>     >     >>     >     >
>     >     >>     >     > I can see that the Zephyr RTOS has been
>     mentioned in
>     >     the FAQ as
>     >     >>     >     > one of the ported OS for non-root cells.
>     >     >>     >     >
>     >     >>     >     > Is there any reference code I can look into?
>     >     >>     >
>     >     >>     >     There is x86 support for Zephyr as Jailhouse
>     "inmate".
>     >     Check out
>     >     >>     >     zephyr/boards/x86/x86_jailhouse/doc/board.rst. If you
>     >     run into
>     >     >>     trouble,
>     >     >>     >     report to the communities.
>     >     >>     >
>     >     >>     >
>     >     >>     > Ah, just noticed that it got removed some time ago:
>     >     >>     >
>     >     >>   
>     >   
>       
> https://github.com/zephyrproject-rtos/zephyr/commit/f3611fdd0c8ca54a9f19bc56a14b4a2fdadaffe3#diff-bb9445fa64739ef6a5a6b59d520deb07
>     >     >>     >
>     >     >>
>     >     >>     Too bad they didn't reach out...
>     >     >>
>     >     >>     > But this could be helpful!
>     >     >>     >  
>     >     >>
>     >     >>     Partly. For ARM, you likely don't need so may changes,
>     see below.
>     >     >>
>     >     >>     >
>     >     >>     >
>     >     >>     >     We could probably also easily support ARM, but
>     the last
>     >     time this
>     >     >>     >     question came up, there was still not A-core
>     support in
>     >     Zephyr
>     >     >>     which is
>     >     >>     >     a precondition.
>     >     >>     >
>     >     >>     >
>     >     >>     > That's what I'm trying to do on IMX8M EVK in spare time.
>     >     There is
>     >     >>     an ongoing
>     >     >>     > PR for adding Cortex-A support in Zephyr, so I'm
>     planning to
>     >     >>     utilize that.
>     >     >>
>     >     >>     That is good news. If you combine that with the device tree
>     >     description
>     >     >>     for inmates, actually those for the Linux cells, you should
>     >     be able to
>     >     >>     boot without code modifications.
>     >     >>
>     >     >>
>     >     >> Don't we need MMU support in inmate? The current ARMv8 PR
>     doesn't
>     >     have the
>     >     >> MMU support.
>     >     >
>     >     > Technically, we don't. Earlier versions of our demo inmates were
>     >     running
>     >     > without MMU as well, but as that implies running without
>     caches as
>     >     well,
>     >     > we changed that. In any case, the inmate starts in reset
>     state, means
>     >     > with MMU (and caches) off.
>     >     >
>     >
>     >
>     > I got it working partially(not fully though). What would be the
>     Flash and
>     > SRAM address would you recommend? The Flash start address should
>     > be 0x0 since that's the CPU default start address, how about SRAM?
>
>     I didn't play with targets where SRAM was involved so far, but I could
>     imagine that it will be easiest to map it at a location where it would
>     appear physically in exclusive use as well.
>
>
> I just got it working. FWIW, the wip commits are
> here: https://github.com/Mani-Sadhasivam/zephyr/commits/jailhouse
>
> There are couple of caveats though:
>
> 1. Zephyr places the vector table at the start/base address and the
> reset entry next to it. But jailhouse didn't seem to find the reset
> entry and it always tries to start from the base address. Is there any
> config option available for fixing this? Since the vector table size is
> fixed, it should be relatively simple to make it start from that address
> I believe.

You can set jailhouse_cell_desc.cpu_reset_address for that.

>
> 2. Currently the GICv3 Rdist address is hardcoded for 2nd core but in
> ideal case we should find it based on MPIDR value as done in jailhouse
> inmate demo. I'm getting faults while trying to read MPIDR_EL1 system
> register, so need to debug it. 
>

Sounds promising! Maybe I will find some time to give it a try during
the holiday season.

Jan

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