On 04/04/2016 09:31 AM, Peter Maydell wrote:
On 4 April 2016 at 17:28, Richard Henderson <r...@twiddle.net> wrote:
On 04/04/2016 08:51 AM, Peter Maydell wrote:
In particular I think if you just do the relevant handling of the tag
bits in target-arm's get_phys_addr() and its subroutines then this
should work ok, with the exceptions that:
* the QEMU TLB code will think that [tag A + address X] and
[tag B + address X] are different virtual addresses and they will
miss each other in the TLB
Yep. Not only miss, but actively contend with each other.
Yes. Can we avoid that, or do we just have to live with it? I guess
if the TCG fast path is doing a compare on full insn+tag then we
pretty much have to live with it.
We have to live with it. Implementing a more complex hashing algorithm in the
fast path is probably a non-starter.
Hopefully if one is using multiple tags, they'll still be in the victim cache
and so you won't have to fall back to the full tlb lookup.
r~
