KVM: arm64: Factor out stage 2 page table data from struct kvm

KVM: arm64: Factor out stage 2 page table data from struct kvm

As we are about to reuse our stage 2 page table manipulation code for
shadow stage 2 page tables in the context of nested virtualization, we
are going to manage multiple stage 2 page tables for a single VM.

This requires some pretty invasive changes to our data structures,
which moves the vmid and pgd pointers into a separate structure and
change pretty much all of our mmu code to operate on this structure
instead.

The new structure is called struct kvm_s2_mmu.

There is no intended functional change by this patch alone.

Reviewed-by: James Morse <[email protected]>
Reviewed-by: Alexandru Elisei <[email protected]>
[Designed data structure layout in collaboration]
Signed-off-by: Christoffer Dall <[email protected]>
Co-developed-by: Marc Zyngier <[email protected]>
[maz: Moved the last_vcpu_ran down to the S2 MMU structure as well]
Signed-off-by: Marc Zyngier <[email protected]>