Re: [Embedded-pv-devel] Xen RAM entry

[RAMYA RAVICHANDRAN <ramya.r@xxxxxxxxxxxxxxxxxxx>]

Hello Andrii,

Thanks a ton for sharing your wonderful experience.

Have attached the dts file for your reference.

Turning Paging on error was resolved by modifying files for MLO.

We have ported kernel 4.4 to accomodate Xen.

We will do the suggested changes and let you know.

Thanking you a lot,

Ramya

On Wed, Dec 6, 2017 at 9:56 PM, Andrii Anisov <andrii.anisov@xxxxxxxxx> wrote:

Hello Ramya,

We have been working on getting Xen hypervisor up on TI DRA7xx J6 platform.

Ouch, I remembered, Jacinto6 for sure.

I see you managed you issues with XEN hang after "Turning paging on". What was that?

Also sharing the dts file with you for reference. 

No dts is attached though. 

We have modified the dom0_mem size from 512MB to 1.5GB, we are observing hang/crash at different functions. (ie powerdomain/ hwmod_init etc).

Recalling my experience with J6 I guess not all MMIO registers accessed by kernel during PRCM setup are described in dts. So XEN traps those accesses from Dom0 and bounce back with data abort. As a quick hack you should add those registers to your dts. I.e. to the dummy device node with reg property contained all required registers. Adding a dra7xx_specific_mapping() function to xen/arch/arm/platforms/omap5.c similar to omap5_specific_mapping() would be more clean way.

You should build your XEN with CONFIG_DEBUG enabled, so you will see print from do_trap_data_abort_guest() right before inject_dabt_exception() call. That print will show what register mappings are missed.

BTW, IIRC, J6 platform code in kernel had smc call in its depths. SMC is not allowed under xen, so you should cut it out as well, otherwise XEN will crash the domain.

Sincerely,

Andrii Anisov.

Attachment: dra7-evm.dts
Description: audio/vnd.dts

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