Re: [Qemu-devel] PowerPC 440 support

[Hollis Blanchard <hollis@penguinppc.org>]

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
> >