As covered in the Linux 4.10 kernel feature overview. the 4.10 cycle is bringing some Zen/Ryzen/17h kernel patches. But still on the kernel mailing list there still are yet-to-be-merged patches mentioning AMD Zeppelin / Family 17h / Zen.
Among the work still baking appears to be multi-IOMMU support with AMD Zen servers will be having multiple IOMMUs and this ~200 lines of code enables said support. The code is now up to its sixth revision but wasn't ready for Linux 4.10. There is also support for perf on 17h with the patch for perf core PMU support on Family 17h CPUs didn't land for 4.10. But again, non-critical functionality for most users. And then just some other small, random patches.
Unfortunately a bit difficult to get a firm understanding if any critical patches are missing due to the less than ideal searching of Patchwork and LKML with relying upon Google and various Zen / 17h queries. But at least with the code in the kernel now it does appear that Zen / Ryzen CPUs should be working, but we should be able to find out in hopefully a few weeks if that really holds up once we're able to test this big AMD CPU advancement and see how well they work out-of-the-box on different released distributions.