Re: [RFC PATCH 00/18] user-creatable cpu clusters

[Damien Hedde]

Ping !

It would be nice to have some rough feedback about this series.
I plan to submit it in 2 sub-series (riscv-array in a separate part) but 
would like to know first if this direction looks ok to you ?

Note that I'm a bit confused by the terminology. Should a "cluster" as 
in "machine topology's cluster" be a 1-1 match with a gdb inferior ?

Thanks,
Damien

On 3/30/22 14:56, Damien Hedde wrote:
> Hi,
>
> This series add devices to be able to user-create (coldplug) cpu
> clusters. The existing cpu cluster dictates how cpus are exposed
> in gdb, but it does not handle the cpu objects creation. This series
> adds a new device to handle both issues and adds support for two
> architectures: arm and riscv.
>
> Please look at patches 2 and 3 for more details about the new device.
>
> Last part concerning the riscv is rfc as I do non-backward compatible
> updates. I'm not sure what migration (or other) constraints we have
> on these machines and I probably need to make some changes to cope
> with them.
>
> This series almost deprecates the cpu-cluster type as all uses
> but one are replaced.
>
> It is organized as follows:
>
> + Patches 1 to 7 adds a new base device to replace cpu-cluster
>
> + Patches 8 and 9 adds an arm specific version and replace existing
>    clusters in the xlnx-zynqmp machine.
>
> + patches 10 to 17 updates the riscv_array. It was already used to
>    create cpus but was not a cpu cluster.
>
> Thanks for any comments,
> --
> Damien
>
> Damien Hedde (18):
>    define MAX_CLUSTERS in cpu.h instead of cluster.h
>    hw/cpu/cpus: introduce _cpus_ device
>    hw/cpu/cpus: prepare to handle cpu clusters
>    hw/cpu/cluster: make _cpu-cluster_ a subclass of _cpus_
>    gdbstub: deal with _cpus_ object instead of _cpu-cluster_
>    hw/cpu/cluster: remove cluster_id now that gdbstub is updated
>    hw/cpu/cpus: add a common start-powered-off property
>    hw/arm/arm_cpus: add arm_cpus device
>    hw/arm/xlnx-zynqmp: convert cpu clusters to arm_cpus
>    hw/riscv/riscv_hart: prepare transition to cpus
>    hw/riscv: prepare riscv_hart transition to cpus
>    hw/riscv/virt: prepare riscv_hart transition to cpus
>    hw/riscv/spike: prepare riscv_hart transition to cpus
>    hw/riscv/riscv_hart: use cpus as base class
>    hw/riscv/sifive_u&microchip_pfsoc: apply riscv_hart_array update
>    hw/riscv: update remaining machines due to riscv_hart_array update
>    hw/riscv/riscv_hart: remove temporary features
>    add myself as reviewer of the newly added _cpus_
>
>   include/hw/arm/arm_cpus.h          |  45 +++++++
>   include/hw/arm/xlnx-zynqmp.h       |   8 +-
>   include/hw/core/cpu.h              |   6 +
>   include/hw/cpu/cluster.h           |  26 ++--
>   include/hw/cpu/cpus.h              |  93 ++++++++++++++
>   include/hw/riscv/microchip_pfsoc.h |   2 -
>   include/hw/riscv/riscv_hart.h      |  25 +++-
>   include/hw/riscv/sifive_u.h        |   2 -
>   gdbstub.c                          |  12 +-
>   hw/arm/arm_cpus.c                  |  63 ++++++++++
>   hw/arm/xlnx-zynqmp.c               | 121 +++++++-----------
>   hw/cpu/cluster.c                   |  53 ++++----
>   hw/cpu/cpus.c                      | 195 +++++++++++++++++++++++++++++
>   hw/riscv/boot.c                    |   2 +-
>   hw/riscv/microchip_pfsoc.c         |  28 +----
>   hw/riscv/opentitan.c               |   4 +-
>   hw/riscv/riscv_hart.c              |  44 ++-----
>   hw/riscv/shakti_c.c                |   4 +-
>   hw/riscv/sifive_e.c                |   4 +-
>   hw/riscv/sifive_u.c                |  31 ++---
>   hw/riscv/spike.c                   |  18 +--
>   hw/riscv/virt.c                    |  79 +++++++-----
>   MAINTAINERS                        |   3 +
>   hw/arm/meson.build                 |   1 +
>   hw/cpu/meson.build                 |   2 +-
>   25 files changed, 612 insertions(+), 259 deletions(-)
>   create mode 100644 include/hw/arm/arm_cpus.h
>   create mode 100644 include/hw/cpu/cpus.h
>   create mode 100644 hw/arm/arm_cpus.c
>   create mode 100644 hw/cpu/cpus.c