How are they going to fix it without some performance penalty. If the memory is in cache isn't there going to be a timing difference? or an extra check will have to be made which is going to have to slow down the lookup?
That's my interpretation though, I don't know enough to say that's the correct interpretation.
Unless I'm mistaken.
Simplistically, it allows TLB-cached page table contents to be tagged with a
context identifier, and limits the lookups in the TLB to only match within
the currently allowed context. TLB cached entires with a different PCID will
be ignored.PCIDs exist for virtual addresses and are implemented in the TLB, not the processor caches. The processor caches are physically indexed, not virtually indexed.
So, does the processor cache have a mechanism to tell which "process" to which a given line belongs? Nope. Two processes (or a process and the kernel) that share memory can be in two PCIDs, but share the processor caches.
10nm + higher frequency?