Comment 7 for bug 1756240

4.13.0-38 introduced a new definition of kvm_mmio() that is backported from 4.15. There's already a list of excepted kernel versions for which the new (4.15) definition should be used. I added ubuntu 4.13.0-38-and-later kernels to that list.

Tested by first successfully building lttng-modules-dkms on 4.13.0-37, then reproducing the problem described here on 4.13.0-38, then applying the code-change and confirming that I can successfully build on both 4.13.0-37 and 4.13.0-38 after that.