On Wed, Aug 28, 2019 at 04:24:45PM +0200, Thomas Gleixner wrote: > Following up on the discussions around the patch Song submitted to 'cure' a > iTLB related performance regression, I picked up Song's patch which makes > clone_page_tables() more robust by handling unaligned addresses proper and > added one which prevents calling into the PTI code when PTI is enabled > compile time, but disabled at runtime (command line or CPU not affected). > > There is no point in calling into those PTI functions unconditionally. The > resulting page tables are the same before and after the change which makes > sense as the code clones the kernel page table into the secondary page > table space which is available but not used when PTI is boot time disabled. > > But even if it does not do damage today, this could have nasty side effect > when the PTI code is changed, extended etc. later. >
Acked-by: Peter Zijlstra (Intel) <pet...@infradead.org>
