KVM: arm64: Return error from kvm_arch_init_vm() on allocation failure

If we fail to allocate the 'supported_cpus' cpumask in kvm_arch_init_vm()
then be sure to return -ENOMEM instead of success (0) on the failure
path.

Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20220609121223.2551-2-will@kernel.org

arch/arm64/kvm/arm.c

@@ -150,8 +150,10 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 	if (ret)
 		goto out_free_stage2_pgd;
 
-	if (!zalloc_cpumask_var(&kvm->arch.supported_cpus, GFP_KERNEL))
+	if (!zalloc_cpumask_var(&kvm->arch.supported_cpus, GFP_KERNEL)) {
+		ret = -ENOMEM;
 		goto out_free_stage2_pgd;
+	}
 	cpumask_copy(kvm->arch.supported_cpus, cpu_possible_mask);
 
 	kvm_vgic_early_init(kvm);