Re: [Qemu-devel] [RFC PATCH 3/4] ppc: Use split I/D mmu modes to avoid flushes on interrupts

[Paolo Bonzini]

On 19/07/2015 14:11, Benjamin Herrenschmidt wrote:
> Ok, I assumed incorrectly that 8 was too much based on your changeset
> comment:
> 
> <<
> At 8k per TLB (for 64-bit host or target), 8 or more modes
>     make the TLBs bigger than 64k, and some RISC TCG backends do
>     not like that.  On the affected hosts, cut the TLB size in
>     half---there is still a measurable speedup on PPC with the
>     next patch.
> >>
>
> IE, you wrote "8 or more".

Indeed... at 8 the TLBs are exactly 64k.

Paolo

> I can easily fold back guest vs. HV into BookE, though we don't
> generally support BookE HV mode anyway in TCG so there's no big hurry in
> doing so (we need to add support for the shadow SPRs and a bunch of
> other things for that to work).