Re: [PATCH 0/4] ppc/pnv: Add chiptod and core timebase state machine models

[Cédric Le Goater]

On 6/4/23 01:36, Nicholas Piggin wrote:
> This adds support for chiptod and core timebase state machine models in
> the powernv POWER9 and POWER10 models.
>
> This does not actually change the time or the value in TB registers
> (because they are alrady synced in QEMU), but it does go through the
> motions. It is enough to be able to run skiboot's chiptod initialisation
> code that synchronises core timebases (after a patch to prevent skiboot
> skipping chiptod for QEMU, posted to skiboot mailing list).
>
> Sorry there was some delay since the last posting. There is a bit more
> interest in this recently but feedback and comments from RFC was not
> forgotten and is much appreciated.
>
> https://lists.gnu.org/archive/html/qemu-ppc/2022-08/msg00324.html
>
> I think I accounted for everything except moving register defines to the
> .h file. I'm on the fence about that but if they are only used in the .c
> file I think it's okay to keep them there for now. I cut out a lot of
> unused ones so it's not so cluttered now.
>
> Lots of other changes and fixes since that RFC. Notably:
> - Register names changed to match the workbook names instead of skiboot.
> - TFMR moved to timebase_helper.c from misc_helper.c
> - More comprehensive model and error checking, particularly of TFMR.
> - POWER10 with multi-chip support.
> - chiptod and core timebase linked via specific state instead of TFMR.
>
> There is still a vast amount that is not modeled, but most of it related
> to error handling, injection, failover, etc that is very complicated and
> not required for normal operation.
>
> Thanks,
> Nick
>
> Nicholas Piggin (4):
>    pnv/chiptod: Add POWER9/10 chiptod model
>    target/ppc: Tidy POWER book4 SPR registration
>    target/ppc: add TFMR SPR implementation with read and write helpers
>    target/ppc: Implement core timebase state machine and TFMR

patch 2-4 could be merged in the next PR. Could you please rebase on
ppc-next and resend ?

Then we still have 2+ weeks to polish pnv/chiptod which would be a
nice addition to QEMU 8.1.

Thanks,

C.


>   hw/ppc/meson.build           |   1 +
>   hw/ppc/pnv.c                 |  38 +++
>   hw/ppc/pnv_chiptod.c         | 488 +++++++++++++++++++++++++++++++++++
>   hw/ppc/pnv_xscom.c           |   2 +
>   hw/ppc/trace-events          |   4 +
>   include/hw/ppc/pnv_chip.h    |   3 +
>   include/hw/ppc/pnv_chiptod.h |  64 +++++
>   include/hw/ppc/pnv_core.h    |   3 +
>   include/hw/ppc/pnv_xscom.h   |   9 +
>   target/ppc/cpu.h             |  40 +++
>   target/ppc/cpu_init.c        |  92 ++++---
>   target/ppc/helper.h          |   2 +
>   target/ppc/spr_common.h      |   2 +
>   target/ppc/timebase_helper.c | 156 +++++++++++
>   target/ppc/translate.c       |  10 +
>   15 files changed, 882 insertions(+), 32 deletions(-)
>   create mode 100644 hw/ppc/pnv_chiptod.c
>   create mode 100644 include/hw/ppc/pnv_chiptod.h