Re: [PATCH v3 8/9] hw/ppc: Add a test machine for the IBM PPE42 CPU

[Miles Glenn <milesg@linux.ibm.com>]

On Wed, 2025-09-10 at 09:10 +0200, Cédric Le Goater wrote:
> On 9/8/25 22:00, Glenn Miles wrote:
> > Adds a test machine for the IBM PPE42 processor, including a
> > DEC, FIT, WDT and 512 KiB of ram.
> > 
> > The purpose of this machine is only to provide a generic platform
> > for testing instructions of the recently  added PPE42 processor
> > model which is used extensively in the IBM Power9, Power10 and
> > future Power server processors.
> > 
> > Signed-off-by: Glenn Miles <milesg@linux.ibm.com>
> > ---
> > 
> > Changes from v2:
> >    - Moved decrementer changes to distinct commit
> >    - Introduced a specific MachineState for the ppe42 Machine
> >    - Use qdev_realize to create the machine
> >    - Use valid_cpu_types to determine validity of CPU
> >    - Changed machine ram limit from 2GB to 512KB
> > 
> >   MAINTAINERS            |   6 +++
> >   hw/ppc/Kconfig         |   9 ++++
> >   hw/ppc/meson.build     |   2 +
> >   hw/ppc/ppe42_machine.c | 102 +++++++++++++++++++++++++++++++++++++++++
> >   4 files changed, 119 insertions(+)
> >   create mode 100644 hw/ppc/ppe42_machine.c
> > 
> > diff --git a/MAINTAINERS b/MAINTAINERS
> > index a07086ed76..52fa303e0a 100644
> > --- a/MAINTAINERS
> > +++ b/MAINTAINERS
> > @@ -1531,6 +1531,12 @@ F: include/hw/pci-host/grackle.h
> >   F: pc-bios/qemu_vga.ndrv
> >   F: tests/functional/test_ppc_mac.py
> >   
> > +PPE42
> > +M: Glenn Miles <milesg@linux.ibm.com>
> > +L: qemu-ppc@nongnu.org
> > +S: Odd Fixes
> > +F: hw/ppc/ppe42_machine.c
> > +
> >   PReP
> >   M: Hervé Poussineau <hpoussin@reactos.org>
> >   L: qemu-ppc@nongnu.org
> > diff --git a/hw/ppc/Kconfig b/hw/ppc/Kconfig
> > index ced6bbc740..3fdea5919c 100644
> > --- a/hw/ppc/Kconfig
> > +++ b/hw/ppc/Kconfig
> > @@ -44,6 +44,15 @@ config POWERNV
> >       select SSI_M25P80
> >       select PNV_SPI
> >   
> > +config PPC405
> > +    bool
> > +    default y
> > +    depends on PPC
> > +    select M48T59
> > +    select PFLASH_CFI02
> > +    select PPC4XX
> > +    select SERIAL
> 
> Does the machine need all the above support ?

No, it only needs PPC4XX.  I'll remove the others.

> 
> > +
> >   config PPC440
> >       bool
> >       default y
> > diff --git a/hw/ppc/meson.build b/hw/ppc/meson.build
> > index 9893f8adeb..170b90ae7d 100644
> > --- a/hw/ppc/meson.build
> > +++ b/hw/ppc/meson.build
> > @@ -57,6 +57,8 @@ ppc_ss.add(when: 'CONFIG_POWERNV', if_true: files(
> >     'pnv_n1_chiplet.c',
> >   ))
> >   # PowerPC 4xx boards
> > +ppc_ss.add(when: 'CONFIG_PPC405', if_true: files(
> > +  'ppe42_machine.c'))
> >   ppc_ss.add(when: 'CONFIG_PPC440', if_true: files(
> >     'ppc440_bamboo.c',
> >     'ppc440_uc.c'))
> > diff --git a/hw/ppc/ppe42_machine.c b/hw/ppc/ppe42_machine.c
> > new file mode 100644
> > index 0000000000..2cfce2503f
> > --- /dev/null
> > +++ b/hw/ppc/ppe42_machine.c
> > @@ -0,0 +1,102 @@
> > +/*
> > + * Test Machine for the IBM PPE42 processor
> > + *
> > + * Copyright (c) 2025, IBM Corporation.
> > + *
> > + * SPDX-License-Identifier: GPL-2.0-or-later
> > + */
> > +
> > +#include "qemu/osdep.h"
> > +#include "qemu/units.h"
> > +#include "qemu/error-report.h"
> > +#include "system/address-spaces.h"
> > +#include "hw/boards.h"
> > +#include "hw/ppc/ppc.h"
> > +#include "system/system.h"
> > +#include "system/reset.h"
> > +#include "system/kvm.h"
> > +#include "qapi/error.h"
> > +
> > +#define TYPE_PPE42_MACHINE MACHINE_TYPE_NAME("ppe42_machine")
> > +typedef MachineClass Ppe42MachineClass;
> > +typedef struct Ppe42MachineState Ppe42MachineState;
> > +DECLARE_OBJ_CHECKERS(Ppe42MachineState, Ppe42MachineClass,
> > +                     PPE42_MACHINE, TYPE_PPE42_MACHINE)
> > +
> > +struct Ppe42MachineState {
> > +    MachineState parent_obj;
> > +
> > +    PowerPCCPU cpu;
> > +};
> > +
> > +static void main_cpu_reset(void *opaque)
> > +{
> > +    PowerPCCPU *cpu = opaque;
> > +
> > +    cpu_reset(CPU(cpu));
> > +}
> > +
> > +static void ppe42_machine_init(MachineState *machine)
> > +{
> > +    Ppe42MachineState *pms = PPE42_MACHINE(machine);
> > +    PowerPCCPU *cpu = &pms->cpu;
> > +
> > +    if (kvm_enabled()) {
> > +        error_report("machine %s does not support the KVM accelerator",
> > +                     MACHINE_GET_CLASS(machine)->name);
> > +        exit(EXIT_FAILURE);
> > +    }
> > +
> > +    /* init CPU */
> > +    object_initialize_child(OBJECT(pms), "cpu", cpu, machine->cpu_type);
> > +    if (!qdev_realize(DEVICE(cpu), NULL, &error_fatal)) {
> > +        return;
> > +    }
> > +
> > +    qemu_register_reset(main_cpu_reset, cpu);
> > +
> > +    /* This sets the decrementer timebase */
> > +    ppc_booke_timers_init(cpu, 37500000, PPC_TIMER_PPE);
> > +
> > +    /* RAM */
> > +    if (machine->ram_size > 512 * KiB) {
> > +        error_report("RAM size more than 512 KiB is not supported");
> > +        exit(1);
> > +    }
> 
> In case of resend, the RAM size could be tested sooner (after kvm_enabled()).
> 

Sure, I'll move it up.

> > +    memory_region_add_subregion(get_system_memory(), 0xfff80000, machine->ram);
> > +}
> > +
> > +
> > +static void ppe42_machine_class_init(ObjectClass *oc, const void *data)
> > +{
> > +    MachineClass *mc = MACHINE_CLASS(oc);
> > +    static const char * const valid_cpu_types[] = {
> > +        POWERPC_CPU_TYPE_NAME("PPE42"),
> > +        POWERPC_CPU_TYPE_NAME("PPE42X"),
> > +        POWERPC_CPU_TYPE_NAME("PPE42XM"),
> > +        NULL,
> > +    };
> > +
> > +    mc->desc = "PPE42 Test Machine";
> > +    mc->init = ppe42_machine_init;
> > +    mc->default_cpu_type = POWERPC_CPU_TYPE_NAME("PPE42XM");
> > +    mc->valid_cpu_types = valid_cpu_types;
> > +    mc->default_ram_id = "ram";
> > +    mc->default_ram_size = 512 * KiB;
> > +}
> > +
> > +static const TypeInfo ppe42_machine_info = {
> > +        .name          = TYPE_PPE42_MACHINE,
> > +        .parent        = TYPE_MACHINE,
> > +        .instance_size = sizeof(Ppe42MachineState),
> > +        .class_init    = ppe42_machine_class_init,
> > +        .class_size    = sizeof(Ppe42MachineClass),
> > +};
> > +
> > +static void ppe42_machine_register_types(void)
> > +{
> > +    type_register_static(&ppe42_machine_info);
> > +}
> > +
> > +type_init(ppe42_machine_register_types);
> > +
> 
> Reviewed-by: Cédric Le Goater <clg@redhat.com>
> 
> Thanks,
> 
> C.
> 

Thank you for your help!

Glenn