On Wed, Nov 1, 2017 at 7:17 AM, Dave Hansen <[email protected]> wrote: > On 11/01/2017 01:03 AM, Andy Lutomirski wrote: >>> This ensures that any futuee context switches will do a full flush >>> of the TLB so they pick up the changes. >> I'm convuced. What was wrong with the old code? I guess I just don't >> see what the problem is that is solved by this patch. > > Instead of flushing *now* with INVPCID, this lets us flush *later* with > CR3. It just hijacks the code that you already have that flushes CR3 > when loading a new ASID by making all ASIDs look new in the future. > > We have to load CR3 anyway, so we might as well just do this flush then.
Would it make more sense to put it in flush_tlb_func_common() instead? Also, I don't understand what clear_non_loaded_ctxs() is trying to do. It looks like it's invalidating all the other logical address spaces. And I don't see why you want a all_other_ctxs_invalid variable. Isn't the goal to mark a single ASID as needing a *user* flush the next time we switch to user mode using that ASID? Your code seems like it's going to flush a lot of *kernel* PCIDs. Can you explain the overall logic?
