On 10/31/18 2:13 PM, Marc Orr wrote: > KVM explicitly cast guest_fpu.state as a fxregs_state in a few > places (e.g., the ioctls). Yet, I see a code path in > fpu__init_system_xstate_size_legacy() that sets > fpu_kernel_xstate_size to sizeof(struct fregs_state). Will this cause > problems? You mentioned that the fpu's state field is expected to > range from ~500 bytes to ~3k, which implies that it should never get > set to sizeof(struct fregs_state). But I want to confirm. It can get set to sizeof(struct fregs_state) for systems where XSAVE is not in use. I was neglecting to mention those when I said the "~500 byte" number. My point was that it can vary wildly and that any static allocation scheme will waste lots of memory when we have small hardware-supported buffers.
