Hypervisor guard hole

[fintelia]

The current platform spec says that...

On RV64I-based Unix-class systems the negative virtual addresses are reserved for the kernel.

However, at least on x86_64 the memory map includes a "guard hole" reserved for the hypervisor. Is there intended to be a similar cutout in riscv, and if so should that be indicated here?

[ahs3]

Do we know if this issue is being actively discussed -- or better yet, completely decided -- anywhere else in the RISC-V community? This seems like it would be a pretty key decision to be made by virtualization folks.

I'm not seeing a virtualization specific task group, though, but this is the sort of memory map issue the OS will definitely need to know about and should be in the platform spec if not handled elsewhere.

[atishp04]

It was agreed that hypervisor guard hole is not required for RISC-V. Here is the relevant discussions happened last year.

https://lists.riscv.org/g/tech-unixplatformspec-archive/search?q=guard+hole

We can close this issue if nobody else objects it to again.

[sorear]

That link is not accessible to the general public.

[atishp04]

The the mailing list is usually available to public. However, this was archived. That's why, it was not available to public.
I can check with you Stephano if there is any more interest about hypervisor guard hole.