Re: Keystone Issue

[Julien Grall <julien@xxxxxxx>]

On 03/06/2020 18:13, CodeWiz2280 wrote:
> Hi Julien,
Hello,

In general, we avoid top post on xen-devel, instead we reply inline. I 
believe gmail should allow you to do it :).
> The offset is already applied to the memory nodes in the device tree, 
> meaning a direct Linux boot from uboot would have only the 36-bit 
> addresses in the device tree (0x8_0000_0000 and 0x8_8000_0000).  Linux 
> would start executing from a 32-bit address space however and then 
> switch over to the aliased 36-bit addresses in the device tree as 
> discussed below by early_paging_init().
> I had to add the 32-bit memory node 0x8000_0000 in uboot in place of the 
> 0x8_0000_0000 node otherwise Xen would detect the 32-bit processor and 
> panic on "Unable to detect the first memory bank" in domain_build.c. 
So for 32-bit Xen requires to have the first bank below 4GB. This is 
because you can't boot from a physical address above 32-bit.
Obviously, this check wouldn't work on your platform because all your 
memory will be above 4GB.
> If 
> I leave only the 36-bit addresses in the device tree and skip past the 
> panic check in domain_build.c, then I could not get the dom0 kernel to 
> boot at all.  I believe I would only see "Serial input to DOM0" and 
> nothing else at that point.
Which would make sense per above.

> Yes, leaving LPAE support on for the kernel is preferred.
Ok, so the solution I suggested below should work. Unfortunately, I 
don't have time to work on it. Although, I would be more than happy to 
answers questions and reviewing the patches.
Would you be willing to have a try to implement it?

Cheers,

--
Julien Grall