KVM: arm64: Introduce separate hypercalls for pKVM VM reservation and initialization

The existing __pkvm_init_vm hypercall performs both the reservation of a
VM table entry and the initialization of the hypervisor VM state in a
single operation. This design prevents the host from obtaining a VM
handle from the hypervisor until all preparation for the creation and
the initialization of the VM is done, which is on the first vCPU run
operation.

To support more flexible VM lifecycle management, the host needs the
ability to reserve a handle early, before the first vCPU run.

Refactor the hypercall interface to enable this, splitting the single
hypercall into a two-stage process:

- __pkvm_reserve_vm: A new hypercall that allocates a slot in the
  hypervisor's vm_table, marks it as reserved, and returns a unique
  handle to the host.

- __pkvm_unreserve_vm: A corresponding cleanup hypercall to safely
  release the reservation if the host fails to proceed with full
  initialization.

- __pkvm_init_vm: The existing hypercall is modified to no longer
  allocate a slot. It now expects a pre-reserved handle and commits the
  donated VM memory to that slot.

For now, the host-side code in __pkvm_create_hyp_vm calls the new
reserve and init hypercalls back-to-back to maintain existing behavior.
This paves the way for subsequent patches to separate the reservation
and initialization steps in the VM's lifecycle.

Signed-off-by: Fuad Tabba <tabba@google.com>
Tested-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>

0 files changed, 0 insertions, 0 deletions