RISC-V: KVM: Implement VMID allocator

We implement a simple VMID allocator for Guests/VMs which:
1. Detects number of VMID bits at boot-time
2. Uses atomic number to track VMID version and increments
   VMID version whenever we run-out of VMIDs
3. Flushes Guest TLBs on all host CPUs whenever we run-out
   of VMIDs
4. Force updates HW Stage2 VMID for each Guest VCPU whenever
   VMID changes using VCPU request KVM_REQ_UPDATE_HGATP

Signed-off-by: Anup Patel <anup.patel@wdc.com>
Acked-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Alexander Graf <graf@amazon.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>

arch/riscv/kvm/Makefile

@@ -9,5 +9,15 @@ KVM := ../../../virt/kvm
 
 obj-$(CONFIG_KVM) += kvm.o
 
-kvm-y += $(KVM)/kvm_main.o $(KVM)/coalesced_mmio.o $(KVM)/binary_stats.o \
-	 $(KVM)/eventfd.o main.o vm.o mmu.o vcpu.o vcpu_exit.o vcpu_switch.o
+kvm-y += $(KVM)/kvm_main.o
+kvm-y += $(KVM)/coalesced_mmio.o
+kvm-y += $(KVM)/binary_stats.o
+kvm-y += $(KVM)/eventfd.o
+kvm-y += main.o
+kvm-y += vm.o
+kvm-y += vmid.o
+kvm-y += tlb.o
+kvm-y += mmu.o
+kvm-y += vcpu.o
+kvm-y += vcpu_exit.o
+kvm-y += vcpu_switch.o