[OpenBIOS] Re: Muti CPU Support

[Jd Lyons]

> On Aug 18, 2019, at 4:49 PM, Mark Cave-Ayland  wrote:
>
> On 18/08/2019 19:41, Jd Lyons via OpenBIOS wrote:
> > I’ve been working a little to see if I can get multi-threaded TGC to work for the Mac OS/X in qemu, but Openbios doesn’t seem to support more than one CPU and doesn’t build any device for a second CPU.
> >
> > I’ve looked at the openbios/arch/ppc/qemu/init.c, and that seems to be the place to apply a patch for multi cpu support, but I don’t really seem any graceful way of doing it.
> >
> > Can anyone offer any help?
> >
> > TGC-Work/bin/qemu-system-ppc  -M mac99,via=pmu -serial stdio -smp 2,cores=2,threads=1 -accel tcg,thread=multi -cpu g4  -boot c  -prom-env auto-boot?=true -prom-env boot-args=-v  -hda /Users/jam/os9.2.1.img   -m 256 -bios /Users/jam/aty7/openbios/obj-ppc/openbios-qemu.elf 
> > heathrow_class_init: init 2
> > core99_machine_class_init: init 2
> > qemu-system-ppc: warning: Guest not yet converted to MTTCG - you may get unexpected results
> > s>> et_property: NULL phandle
> > > > =============================================================
> > > > OpenBIOS 1.1 [Aug 6 2019 02:05]
> > > > Configuration device id QEMU version 1 machine id 1
> > > > CPUs: 2
> > > > Memory: 256M
> > > > UUID: 00000000-0000-0000-0000-000000000000
> > > > CPU type PowerPC,G4
> >
> > milliseconds isn't unique.
> > > > switching to new context:
> > > > call-method slw_update_keymap failed with error ffffffdf
> > > > call-method slw_update_keymap failed with error ffffffdf
>
> You can grab the current number of CPUs from the fwcfg interface at register
> FW_CFG_NB_CPUS. As a starting point I'd try writing a for loop somewhere around
> https://github.com/openbios/openbios/blob/master/arch/ppc/qemu/init.c#L996 to create
> the relevant number of CPU nodes in the DT.
>
> Once that is done I suspect the next part of the puzzle will be figuring out how to
> wire up the machine and its IRQs correctly...
>
> ATB,
>
> Mark.

Thanks Mark,

Doing this gets me 2 /cpus but both are @0

/* This needs adjusting if #size-cells gets increased.
       Alternatively use multiple (address, size) tuples. */
    PUSH(ram_size & 0xffffffff);
    fword("encode-int");
    fword("encode+");
    push_str("reg");
    fword("property");

cpu = id_cpu();
    cpu->initfn(cpu);
    printk("CPU type %s\n", cpu->name);

cpu = id_cpu();
    cpu->initfn(cpu);
    printk("CPU type %s\n", cpu->name);

snprintf(buf, sizeof(buf), "/cpus/%s", cpu->name);
    ofmem_register(find_dev("/memory"), find_dev(buf));
    node_methods_init(buf);

How would I go about making the second cpu be @1?

I can’t seem to figure where in the code the cpu is set to @0, is this a function of Openbios or Qemu?