KVM: Move wiping of the kvm->vcpus array to common code

All architectures have similar loops iterating over the vcpus,
freeing one vcpu at a time, and eventually wiping the reference
off the vcpus array. They are also inconsistently taking
the kvm->lock mutex when wiping the references from the array.

Make this code common, which will simplify further changes.
The locking is dropped altogether, as this should only be called
when there is no further references on the kvm structure.

Reviewed-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Message-Id: <20211116160403.4074052-2-maz@kernel.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index e4727dc..362b10c 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -175,19 +175,11 @@ vm_fault_t kvm_arch_vcpu_fault(struct kvm_vcpu *vcpu, struct vm_fault *vmf)
  */
 void kvm_arch_destroy_vm(struct kvm *kvm)
 {
-	int i;
-
 	bitmap_free(kvm->arch.pmu_filter);
 
 	kvm_vgic_destroy(kvm);
 
-	for (i = 0; i < KVM_MAX_VCPUS; ++i) {
-		if (kvm->vcpus[i]) {
-			kvm_vcpu_destroy(kvm->vcpus[i]);
-			kvm->vcpus[i] = NULL;
-		}
-	}
-	atomic_set(&kvm->online_vcpus, 0);
+	kvm_destroy_vcpus(kvm);
 }
 
 int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)