Re: [Qemu-devel] sparc64-softmmu Questions

[Blue Swirl]

On Wed, Oct 21, 2009 at 10:19 PM, Nick Couchman <address@hidden> wrote:
>>>> On 2009/10/21 at 13:06, Blue Swirl <address@hidden> wrote:
>> On Wed, Oct 21, 2009 at 7:41 PM, Nick Couchman <address@hidden> wrote:
>>> I have a couple of questions regarding sparc64 softmmu support in Qemu:
>>> - Is this part of Qemu being actively developed?  Judging by the commits to
>> the git repo, it doesn't look like there's a whole lot of focus on
>> development of this right now?
>>
>> It's more active architecture than many others, but of course x86 is the
>> king.
>>
>>> - Does anyone know what's left to be done for the sparc64 target to get it
>> to boot Solaris correctly?  Is there any sort of a bug repository for Qemu
>> that might list these things?  Or maybe someone has a list in their head?
>>
>> There are several areas which need improvement. Sparc64 CPU emulation
>> seems to be mostly OK. Sun4u devices are a bit bogus and sun4v devices
>> do not exist yet. The Forth side of OpenBIOS is buggy, but we don't
>> have enough Forth experts.
>>
>>> - As has already been mentioned on this list, Sun has released the Open Boot
>> PROM code (at least the sun4v version of it) under the BSD and GPL licenses.
>> What would it take to get Qemu to use the OBP code instead of OpenBIOS?
>> Looks like the OBP output isn't really an executable, and it seems like
>> sparc64-softmmu will only load Sparc ELF binaries for the BIOS.
>>
>> The hypervisor code below OBP is targeting Sun's Legion simulator, not
>> ours or even native host.
>>
>> For Solaris/Sparc64 emulation, there is more than one way:
>> - sparc64-softmmu/sun4u + OpenBIOS (default stack): problems described above
>> - sparc64-softmmu/sun4v + hypervisor + OBP: need to port the
>> hypervisor to QEMU, maybe fix/implement a few devices
>> - sparc64-solaris-user or sparc32plus-solaris-user (I sent a first cut
>> patch to list some time ago): the licenses are incompatible and the
>> user emulator would not be as useful as full system emulator.
>
> Thanks for the updates.  I didn't realize that the OBP was written 
> specifically for the emulator - I thought it was a standard PROM code.  Would 
> there be any use in borrowing code from the OpenSPARC OBP source and porting 
> that over to OpenBIOS?  Maybe that's just one of the things waiting on a 
> Forth expert?  Or are their licensing issues there that would make such a 
> task legally challenging?

I think the license are compatible, but only the Forth expert can say
whether it would make sense. There are some other Forth boot prom
sources in http://www.openfirmware.info/.

> For the devices, the sun4u platform is PCI-based, correct?  I assume, then, 
> that peripheral devices, like network cards, video cards, etc., are shared 
> from the rest of the Qemu code base?  What devices are lacking?

Yes, PCI devices should be fine. There's a TODO list under
target-sparc, not all items in the list are critical though.

> I'd also love to see a sparc64-solaris-user application - mainly, I'm 
> interested in some sort of application that will let me run my legacy 
> Solaris/SPARC application on Linux/x86(_64).  We were using a product called 
> Transitive for that for a while, but IBM recently acquired Transitive and has 
> decided to bury the technology in one of their products and not offer it as a 
> stand-alone application anymore.  So, I'm looking for alternatives.  Do you 
> still have those patches?  What's incompatible about the licensing?

The patch and some discussion can be found here:
http://lists.gnu.org/archive/html/qemu-devel/2009-04/msg00824.html