Crash on ARM with LPA/LPA2

[mkroening]

Starting with QEMU@7a928f (QEMU 7), QEMU emulates LPA on -cpu max. We might want to support that properly instead of opting out of the extension (hermit-os/loader#107).

[mkroening]

Since the loader itself is running fine, but the kernel is crashing, I moved this issue to the kernel repo.

When running Hermit on ARM QEMU with -cpu max, we panic:

[            ][0][INFO  paging    ] Physical address range: 4194304GB
[            ][0][INFO  paging    ] Support of 4KB pages: false
[            ][0][INFO  paging    ] Support of 16KB pages: false
[            ][0][INFO  paging    ] Support of 64KB pages: true
[0][PANIC] panicked at src/arch/aarch64/mm/paging.rs:736:5:
assertion failed: t_gran4

-cpu max,lpa2=off works fine, reported by @cagatay-y.

@cagatay-y also reported:

I also tried it with just max and an issue came up with the kernel thinking that 4 KiB pages are not supported. There is a third variant of 4 KiB page support register that is described as "4KB granule supports 52-bit input addresses and can describe 52-bit output addresses" but it is currently not recognized by the aarch64-cpu crate. When I added it to the crate and changed the kernel to accept the 3rd variant, everything seems to work fine.

The corresponding PR is rust-embedded/aarch64-cpu#82.