Re: [Qemu-devel] [PATCH v7 05/32] target-arm: make arm_current_el() return EL3

[Richard Henderson]

On 01/19/2015 05:22 AM, Peter Maydell wrote:
> Richard: do you have a feel for how expensive it is to
> have lots and lots of mmu modes? I might be able to
> merge "S EL1" with "NS EL1 stage 1+2" and ditto "S EL0"
> with "NS EL0 stage1 + 2" but we'd need to do more TLB
> flushing and it's not clear to me currently exactly
> where the extra flushes would have to go...

It's 10k per mmu mode, more or less.  That's what you've
got to memset (to -1) whenever a flush occurs.

With the obvious mathematics wrt flush rate that implies.


r~