On Mon, Nov 13, 2017 at 6:28 PM, Linus Torvalds <torva...@linux-foundation.org> wrote: > On Mon, Nov 13, 2017 at 6:25 PM, Andy Lutomirski <l...@kernel.org> wrote: >> On Mon, Nov 13, 2017 at 11:36 AM, Linus Torvalds >> <torva...@linux-foundation.org> wrote: >>> >>> I forget what the actual size is, but aligning the hardware TSS struct >>> to 128 bytes might be sufficient. It's not that big. >> >> 104 bytes, so it's probably already fine. For anything except an >> actual task switch, only the first 12 or so bytes matter. > > Note that historically, about half of the Intel errata (that don't get > fixed) are about TSS in oddball situations, mainly page crossers. > > I may be exaggerating just a tiny bit, but it's definitely a "don't do it".
:) I suspect the major case where this matters is when we do a task switch, which only ever happens on 32-bit double faults, at which point we're already seriously screwed. But yes, I agree.
