ARM: KVM: add architecture specific hook for capabilities

Most of the capabilities are common to both arm and arm64, but
we still need to handle the exceptions.

Introduce kvm_arch_dev_ioctl_check_extension, which both architectures
implement (in the 32bit case, it just returns 0).
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Christoffer Dall <cdall@cs.columbia.edu>

arch/arm/include/asm/kvm_host.h

@@ -214,6 +214,11 @@ static inline void __cpu_init_hyp_mode(unsigned long long boot_pgd_ptr,
 	kvm_call_hyp((void*)hyp_stack_ptr, vector_ptr, pgd_ptr);
 }
 
+static inline int kvm_arch_dev_ioctl_check_extension(long ext)
+{
+	return 0;
+}
+
 int kvm_perf_init(void);
 int kvm_perf_teardown(void);
 

arch/arm/kvm/arm.c

@@ -206,7 +206,7 @@ int kvm_dev_ioctl_check_extension(long ext)
 		r = KVM_MAX_VCPUS;
 		break;
 	default:
-		r = 0;
+		r = kvm_arch_dev_ioctl_check_extension(ext);
 		break;
 	}
 	return r;