[OpenBIOS] OpenSolaris starts to live on SPARC64

[Artyom Tarasenko]

2010/4/3 Blue Swirl <blauwirbel at gmail.com>:
> On 4/3/10, Artyom Tarasenko <atar4qemu at googlemail.com> wrote:
>> 2010/4/3 Mark Cave-Ayland <mark.cave-ayland at siriusit.co.uk>:
>>
>> > Mark Cave-Ayland wrote:
>>  >  (I wonder if some MMU/CPU emulation is broken somewhere?)
>>
>>
>> Actually a very good question. Does qemu emulate any sun4u
>>  machine good enough to have a chance running with OBP?
>>  It may be a good strategy for fixing the  "hardware".  At least
>>  it was fruitful on sun4m.
>>  Blue?
>
> One problem with that strategy is that QEMU does not implement any
> real machines now. Typical Ultra machines had HME NICs, 53C875 SCSI
> controller but we have random PCI NICs and IDE (CMD646 exists but
> usually it's only used for CDROM). OSes probably don't care whether
> the machine matches any real one or not.
>
> One solution would be to implement the first Ultra machines, which
> were partially SBUS based and had many common devices with Sun4m.
>
> We could also implement some mid-class machine with HME and 53C875 (it
> may even be similar to lsi53c895a, which we have). PCI bridging does
> not work well in QEMU. The docs aren't very good I think. This is
> closest to what we have now. It could be interesting to see what OBP
> from a real machine would think of the QEMU machine.

How is SBUS connected to the IO-MMU? Directly or through a PCI bridge?
Quick google search didn't help me to find it. I only found that in the Russian
sparc32 PCI machine (Elbrus-90)  SBUS is connected through a PCI-bridge.
If that's the case in early Ultras too, OBP probably won't be able to tell us
much via the serial port connected to the SBUS.

> Third option would be to aim for T1/T2 class machines. The docs are
> good and there is even Verilog implementation to compare with because
> most of the devices are inside the CPU. The devices aren't very simple
> and there is very little commonality with old HW. There are also CPU
> features to be implemented (CMT). The boot ROM architecture is
> interesting, there is a hypervisor which OBP uses. Everything is open
> source, including the CPU. QEMU's Niagara machine can boot the
> hypervisor, which will output a few lines before crashing.

How about one more. The fourth option (or the second one for the OpenBIOS
team) would be using Sun's legion T1/T2 emulator as the hardware for the
OpenBIOS. It may be the shortest path to get OpenSolaris booting under
OpenBIOS.

> The options aren't mutually exclusive, so if we had an infinite number
> of monkeys we could advance in all three areas simultaneously. There's
> a lot of playground. :-)
>


-- 
Regards,
Artyom Tarasenko

solaris/sparc32 under qemu blog: http://tyom.blogspot.com/