At this point it looks to only affect Intel processors. I'm hoping they can come up with better solutions in time. This could really hurt many businesses and the business models of cloud computing vendors and many more. This is a quote from the article.
"AMD processors are not subject to the types of attacks that the kernel page table isolation feature protects against. The AMD microarchitecture does not allow memory references, including speculative references, that access higher privileged data when running in a lesser privileged mode when that access would result in a page fault.
A key word here is "speculative." Modern processors, like Intel's, perform speculative execution. In order to keep their internal pipelines primed with instructions to obey, the CPU cores try their best to guess what code is going to be run next, fetch it, and execute it.
It appears, from what AMD software engineer Tom Lendacky was suggesting above, that Intel's CPUs speculatively execute code potentially without performing security checks. It seems it may be possible to craft software in such a way that the processor starts executing an instruction that would normally be blocked – such as reading kernel memory from user mode – and completes that instruction before the privilege level check occurs.
That would allow ring-3-level user code to read ring-0-level kernel data. And that is not good."
And an update on the same article:
"Finally, macOS has been patched to counter the chip design blunder since version 10.13.2, according to operating system kernel expert Alex Ionescu. And it appears 64-bit ARM Linux kernels will also get a set of KAISER patches, completely splitting the kernel and user spaces, to block attempts to defeat KASLR. "