system emulation with kvm guests inside

[Janne Karhunen]

Hi,

I'm working on a hypervisor that unmaps the kvm guests from the host
memory, among other things a bit different from the regular KVM.
Overall it seems to run and the security is improving daily
(https://github.com/jkrh/kvms). Hopefully next week we'll merge a new
research feature where we make the MMU run backwards for pretty funny
use cases.

That said, what's the status of the TCG system emulation if the KVM
guests are executed in it? While it does work for me, it works even
too well at times and allows access to mappings it really should not
per the second level page tables. Is this to be expected or are we
looking at a bug in the qemu softmmu or our code? If this is to work
correctly and there are no shortcuts in the QEMU when it does
(especially) virtio in such cases I suppose I need to dig into the
issue in the emulation a bit deeper.

Btw the 'mmu' debug option doesn't seem to do much these days. Is
there any other way to get output from the softmmu / tlb state on
arm64?


--
Janne