On Fri, Aug 16, 2019 at 9:56 AM Richard Miller <9fans@hamnavoe.com> wrote:
> > Do you mean something like BlackIce II (I'm under RV32I)?
>
> Yes, I have tried various soft cores on BlackIce (including
> one of my own design, for fun); also real silicon HiFive-1.
> So far none of these has had an MMU, which is required for
> Plan 9 (though not for Inferno).

Speaking of RISC-V with MMU for Plan 9, Kendryte K210 is a 28nm MCU
with dual core RV64GC and Linux capable MMU (!). It has 8MB onchip
SRAM and also NN, FFT accelerators.
I think that makes a good platform for Plan 9 on RISC-V, on a real silicon.
It also has a lot of really cheap evaluation board options available.
(The only other currently available RV64GC w/ MMU silicon is the
Hifive unleashed, which is very expensive.)

The only major problem of K210 is that its IO capabilities are fairly
limited and you need external Ethernet/Wifi solutions on SPI bus,
which is likely slow.