Re: [PATCH 21/23] x86, pcid, kaiser: allow flushing for future ASID switches

[Dave Hansen]

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.