Re: [Qemu-devel] Adding SMP support for Sparc Target

[Damien Hilloulin]

Le 06/11/2014 19:23, Artyom Tarasenko a écrit :
> On Thu, Nov 6, 2014 at 6:36 PM, Damien Hilloulin
> <address@hidden> wrote:
> > Le 06/11/2014 16:27, Artyom Tarasenko a écrit :
> > > Hello Damien,
> > >
> > > On Thu, Nov 6, 2014 at 8:38 AM, Damien Hilloulin
> > > <address@hidden> wrote:
> > > > Hello everyone,
> > > >
> > > > I'm a newcomer in QEMU and my goal would be to port an existing system
> > > > simulator using another emulator to QEMU.
> > > > Some work has already been done, and Sparc has been the main target so
> > > > far
> > > > because of its simplicity (and because we have a very good support for
> > > > Sparc
> > > > with the other emulator).
> > > > QEMU is great, open-source (contrary to the other emulator we have been
> > > > using in the past), and that's why we are aiming at using it.
> > > >
> > > > However, it seems that the Sparc targets doesn't really support SMP/CMT
> > > > as
> > > > of now. So I am considering two possibilities:
> > > > - adding SMP support in QEMU for the Sparc targets (and contribute it to
> > > > QEMU :) )
> > > Do you mean a) emulating multiple guest cores on in a single host
> > > thread, or b) emulating multiple guest cores in multiple host threads?
> > a) Would be enough for us (but b) would be amazing) !
> > > The former (a) should be relative easy for a sun4m platform: just have
> > > to put the CPUs at the proper place in the system bus and fill the CPU
> > > Module Ids (MIDs) with the proper data.
> > Could you please explain it with some more details? I don't really know how
> > to do that (yet)...
> > We are really interested in such a support for Sparc64, so I think that it
> > would be for sun4u machines only.
> > Would the changes would be the same or would there be more work?
> Taking into account the overall status of sun4u emulation, it is a bit
> more work.
> AFAIR the SMP-related registers of Ultrasparc CPUs/chipsets are not implemented.
> Additionally there are currently no sun4u SMP boards emulated in QEMU,
> but I think this is a smaller issue.
>
> Also some support in OpenBIOS might be necessary. Mark can surely tell more.
>
> Artyom
Ok... Quite bad that's not as easy than for Sparc32, but I think that's 
still better for us than focusing on ARM direclty.
Would someone have a little bit of documentation about those topics 
(specific registers/interrupts/bios)?
Any help is welcome!

Damien.