Re: [Qemu-devel] PowerPC 440 support

[Baojun Wang <wangbj@gmail.com>]

It seems most boards will converted to the device tree infrastructure?

but I think we will need a firmware first before loading the linux
kernel, I don't know if qemu-system-ppcemb could run kernel directly
without a firmware..

  Best Regards,
Wang

On Mon, Jun 15, 2009 at 3:46 AM, Hollis Blanchard<hollis@penguinppc.org> wrote:
> My 440 board is inaccessible for a couple weeks, so I can't test your
> patch. That said, the code looks fine.
>
> However, I wonder what your goal is? You want to be able to create a
> Bamboo board with e.g. a 750 processor? I don't think that would help
> the original poster, and I'm not sure how useful it is, but I don't
> object...
>
> Either way I guess it will become a non-issue once PowerPC boards are
> converted to the device tree infrastructure.
>
> -Hollis
>
> On Sun, Jun 14, 2009 at 1:33 PM, Blue Swirl<blauwirbel@gmail.com> wrote:
>> Sorry, I was very confused (I didn't look at ppc440.c).
>>
>> For some reason, CPU model can't be specified on the command line. The
>> patch allows this, does it look OK?
>>
>> Is there a kernel and initrd somewhere, so I could test this?
>>
>> Currently I get (no kernel or ROM, so nothing to execute):
>> Truncating memory to 128 MiB to fit SDRAM controller limits.
>> ppc405_serial_init: offset 0000000000000300
>> QEMU 0.10.50 monitor - type 'help' for more information
>> (qemu) qemu: fatal: Trying to execute code outside RAM or ROM at
>> 0x00000000fffffffc
>>
>> NIP 00000000fffffffc   LR 0000000000000000 CTR 0000000000000000 XER 00000000
>> MSR 0000000000000000 HID0 0000000000000300  HF 0000000000000000 idx 1
>> Segmentation fault
>>
>> On 6/14/09, Hollis Blanchard <hollis@penguinppc.org> wrote:
>>> Yes, I wrote the code you quoted.
>>>
>>>  In case there is any confusion, let me restate: You can boot a Bamboo
>>>  (PowerPC 440) guest under KVM on a PowerPC 440 host. KVM bypasses
>>>  qemu's CPU emulation (TCG), but uses qemu's device emulation.
>>>  Therefore, if someone were to implement 440 core emulation in qemu,
>>>  you could boot a 440 kernel with qemu without KVM.
>>>
>>>  Most devices found on 440 SoCs are the same as or very similar to the
>>>  devices found on 405 SoCs. Qemu's 440 device emulation isn't perfect,
>>>  but because Linux is highly modular, with a modified device tree you
>>>  can boot it. See pc-bios/bamboo.dts.
>>>
>>>  -Hollis
>>>
>>>  On Sat, Jun 13, 2009 at 10:47 PM, Baojun Wang <wangbj@gmail.com> wrote:
>>>  >
>>>  > in hw/ppc440.c:
>>>  >
>>>  >    env = cpu_ppc_init("440EP");
>>>  >    if (!env && kvm_enabled()) {
>>>  >        /* XXX Since qemu doesn't yet emulate 440, we just say it's a 405.
>>>  >         * Since KVM doesn't use qemu's CPU emulation it seems to be working
>>>  >         * OK. */
>>>  >        env = cpu_ppc_init("405");
>>>  >    }
>>>  >    if (!env) {
>>>  >        fprintf(stderr, "Unable to initialize CPU!\n");
>>>  >        exit(1);
>>>  >    }
>>>  >
>>>  > also in hw/ppc.c:
>>>  >
>>>  > I can find ppc40x_irq_init/e500_irq_init(used mpc8544ds), but there is
>>>  > no ppcbooke_irq_init? It seems hw/ppc405_uc.c is emulation for DCRs,
>>>  > PLB, DMA, GPIO, I2C.., but there is no hw/ppc44x_uc.c.
>>>  >
>>>  > the qemu source I used is 0.10.5.
>>>  >
>>>  > Also in ppc/translate_init.c, there lots of CONFIG_USER_ONLY, but I
>>>  > many of them are DEBUG or CACHE related SPR emulation, and since qemu
>>>  > doesn't emulate cache, I think it's OK.
>>>  >
>>>  >  Thanks,
>>>  > Wang
>>>  >
>>>  > On Sun, Jun 14, 2009 at 1:47 AM, Hollis Blanchard<hollis@penguinppc.org> wrote:
>>>  > > On Fri, Jun 12, 2009 at 10:48 AM, Blue Swirl <blauwirbel@gmail.com> wrote:
>>>  > >>
>>>  > >> On 6/11/09, Baojun Wang <wangbj@gmail.com> wrote:
>>>  > >> > could qemu emulate some board like bamboo (without kvm) or MPC8544ds
>>>  > >> > now? Thanks
>>>  > >>
>>>  > >> Yes, if someone adds emulation for these devices: UIC, PLB, DMA, POB,
>>>  > >> EBC, IIC, ZMII. Maybe some are not needed in all cases.
>>>  > >
>>>  > > No, qemu still doesn't emulate Book E cores, such as the PowerPC 440 in a
>>>  > > Bamboo board.
>>>  > >
>>>  > > UIC is of course emulated, otherwise KVM guests on 440 wouldn't get very
>>>  > > far. :) Enough 440 SoC devices are emulated to support Linux boot with a
>>>  > > properly stripped device tree.
>>>  > >
>>>  > > -Hollis
>>>  > >
>>>
>>
>