[PATCH 0/3] kvmtool: Limit IPA space to what is actually required

[Marc Zyngier]

KVM hacking on the Apple M1 SoC has shown that kvmtool (and other
VMMs) make pretty poor use of the IPA space parameter (read: do not
use it and just pass 0). This results in a guest that cannot boot
(thanks to a kernel bug), but in general means we don't benefit from
smaller page tables at stage-2.

This series does two things:
- It switches kvmtool away from the default 40bit, allowing large VMs
  to be created (I have booted a 4TB VM)
- It reduces the requested IPA space to be as small as possible

It all looks really good, except that the last patch trips yet another
bug in KVM so better not apply it. Yet.

Marc Zyngier (3):
  kvmtool: Abstract KVM_VM_TYPE into a weak function
  kvmtool: arm64: Use the maximum supported IPA size when creating the
    VM
  kvmtool: arm64: Configure VM with the minimal required IPA space

 arm/aarch64/include/kvm/kvm-arch.h | 19 ++++++++++++++---
 arm/aarch64/kvm.c                  | 33 ++++++++++++++++++++++++++++++
 include/kvm/kvm.h                  |  1 +
 kvm.c                              |  7 ++++++-
 4 files changed, 56 insertions(+), 4 deletions(-)

-- 
2.30.0