Doorbell emulation for nested KVM guests in V1 API is broken because of
2 reasons:
1. L0 presenting H_EMUL_ASSIST to L1 instead of H_FAC_UNAVAIL
2. Broken plumbing for passing around doorbell state.

Fix the trap passed to L1 and the plumbing for maintaining doorbell
state.

Gautam Menghani (3):
  Revert "KVM: PPC: Book3S HV Nested: Stop forwarding all HFUs to L1"
  KVM: PPC: Book3S HV: Stop using vc->dpdes for nested KVM guests
  KVM: PPC: Book3S HV: Avoid returning to nested hypervisor on pending
    doorbells

 arch/powerpc/kvm/book3s_hv.c        | 41 ++++++++---------------------
 arch/powerpc/kvm/book3s_hv_nested.c | 14 +++++++---
 2 files changed, 21 insertions(+), 34 deletions(-)

-- 
2.45.2

On Sat, 09 Nov 2024 12:02:54 +0530, Gautam Menghani wrote:
> Doorbell emulation for nested KVM guests in V1 API is broken because of
> 2 reasons:
> 1. L0 presenting H_EMUL_ASSIST to L1 instead of H_FAC_UNAVAIL
> 2. Broken plumbing for passing around doorbell state.
> 
> Fix the trap passed to L1 and the plumbing for maintaining doorbell
> state.
> 
> [...]

Applied to powerpc/topic/ppc-kvm.

[1/3] Revert "KVM: PPC: Book3S HV Nested: Stop forwarding all HFUs to L1"
      https://git.kernel.org/powerpc/c/ed351c57432122c4499be4f4aee8711d6fa93f3b
[2/3] KVM: PPC: Book3S HV: Stop using vc->dpdes for nested KVM guests
      https://git.kernel.org/powerpc/c/0d3c6b28896f9889c8864dab469e0343a0ad1c0c
[3/3] KVM: PPC: Book3S HV: Avoid returning to nested hypervisor on pending doorbells
      https://git.kernel.org/powerpc/c/26686db69917399fa30e3b3135360771e90f83ec

cheers