Re: Xen for Apple Silicon (M1 and beyond)

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 24 Jul 2024, Techguru wrote:
> Hello,
> Stefano, on IRC, suggested that I start a discussion on this mailing
> list regarding my intention to bring up a fully function XEN on Apple
> Silicon (M1 and beyond).  I am in the process of getting up to speed
> on your governance policies, applied for Coverity access to use some
> of the known issues there as training wheels, and putting my gitlab
> fork into good working order with CI.
> 
> I would rather not duplicate effort which has already been proposed,
> so definitely open to any pointers, any requests for how to chunk
> things into smaller patches, any requests for particular
> ordering/sequencing of patch sets.
> 
> Some obvious areas:
> 16k pages;

For this, do you know if 4K pages are supported (in addition to 16K)? It
would be a lot easier to keep running Xen using 4K pages and run guests
on top of Xen which use 16K pages. In the past, we had Linux using 64K
pages running on top of Xen using 4K pages for example.


> device trees;

You might be able to use the device tree which is used to boot Linux on
Apple silicon


> interrupts;

If the interrupt controller is not an ARM GIC, then we need a driver for
it in Xen


> power management;
> any essential device drivers.

In addition to the interrupt controller, we might need drivers for the
UART or framebuffer to see Xen output. Also the timer. Xen has a driver
for the ARM Generic Timer but if Apple has a different timer, that is
something else to consider.