tree 7b23dd784c105be4fdaf3ee449ed15880663afbc
parent b4f097492a154f67bca0def5739564702a04d300
author Mostafa Saleh <smostafa@google.com> 1686228054 +0000
committer Mostafa Saleh <smostafa@google.com> 1688998323 +0000

KVM: arm64: iommu: smmu: VM teardown for stage-1

When a VM is teardown, it may still have pages in mapped in it's
IOMMU, these pages are refcounted and never reclaimed.

To cleanly teardown IOMMUs from VMs, 2 operations are needed:
- Clear STE/CDs to have invalid configs implemented by
  kvm_iommu_force_detach_dev
- Free all page tables used and decrement the refcount for page
  mapped, Implemented in kvm_iommu_free_guest_domains, to avoid
  walking all domain space, we add nr_domains for hyp_vm so we exit
  early once all domains are freed. Another apporach that requires
  dynamic allocation is to have a list of domains belong to the
  hyp_vm.

One difference between teardown and other IOMMU operations, is that
the hyp_vcpu is not loaded, so pkvm_get_loaded_hyp_vcpu() can't be
used in reclaim path.
A new per-cpu variable is added to mark the context of teardown
operation.

Signed-off-by: Mostafa Saleh <smostafa@google.com>