It claims to also allow you to read any data loaded into a vector register, any data loaded from a {rep mov} (i.e. memcpy), any data used by crypto acceleration, and a bunch more. Basically, the only data it does not let you read is regular loads into the regular GPRs (i.e. what would be a register load in a RISC architecture) though if you save/restore during context switches using the special instructions you will leak the values at the time of the context switch.

This is about as close to a total cross-process data leak as can be imagined.