KVM: Future-proof device assignment ABI

Reserve some space so we can add more data.

Signed-off-by: Avi Kivity <[e-mail]>

include/linux/kvm.h

···
 	__u32 busnr;
 	__u32 devfn;
 	__u32 flags;
+	union {
+		__u32 reserved[12];
+	};
 };
 
 struct kvm_assigned_irq {
···
 	__u32 host_irq;
 	__u32 guest_irq;
 	__u32 flags;
+	union {
+		__u32 reserved[12];
+	};
 };
 
 #define KVM_DEV_ASSIGN_ENABLE_IOMMU	(1 << 0)