On Mon, Oct 28, 2024 at 06:56:15PM -0700, Josh Poimboeuf wrote: > The barrier_nospec() in 64-bit __get_user() is slow. Instead use > pointer masking to force the user pointer to all 1's if a previous > access_ok() mispredicted true for an invalid address.
Linus pointed out that __get_user() may be used by some code to access both kernel and user space and in fact I found one such usage in vc_read_mem().... So I self-NAK this patch for now. Still, it would be great if patch 1 could get merged as that gives a significant performance boost. -- Josh
