Re: [PATCH v5 4/5] ppc/pnv: Introduce user creatable pnv-phb4 devices

[Daniel Henrique Barboza]

On 1/11/22 11:42, Cédric Le Goater wrote:
> On 1/11/22 14:10, Daniel Henrique Barboza wrote:
> > This patch introduces pnv-phb4 user creatable devices that are created
> > in a similar manner as pnv-phb3 devices, allowing the user to interact
> > with the PHBs directly instead of creating PCI Express Controllers that
> > will create a certain amount of PHBs per controller index.
> >
> > We accomplish this by doing the following:
> >
> > - add a pnv_phb4_get_stack() helper to retrieve which stack an user
> > created phb4 would occupy;
> >
> > - when dealing with an user created pnv-phb4 (detected by checking if
> > phb->stack is NULL at the start of phb4_realize()), retrieve its stack
> > and initialize its properties as done in stk_realize();
> >
> > - use 'defaults_enabled()' in stk_realize() to avoid creating and
> > initializing a 'stack->phb' qdev that might be overwritten by an user
> > created pnv-phb4 device. This process is wrapped into a new helper
> > called pnv_pec_stk_default_phb_realize().
> >
> > Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
>
> Reviewed-by: Cédric Le Goater <clg@kaod.org>
>
> Nothing is left in the stack model. I think the next cleanup is to
> get rid of it.


The first step would be to move some MemoryOps from the stack to the phb, then
little by little we can get into a point where the stack will just be a pointer
to its phb.

This is something that we can keep working on in smaller bits here and there.
I mean, assuming that we're not going to use this code base for PHB5. If that's
the case then I can prioritize this cleanup.



Thanks,

Daniel




> Thanks,
>
> C.
>
>
> > ---
> >   hw/pci-host/pnv_phb4.c     | 74 ++++++++++++++++++++++++++++++++++++--
> >   hw/pci-host/pnv_phb4_pec.c | 17 +++++++--
> >   hw/ppc/pnv.c               |  2 ++
> >   3 files changed, 89 insertions(+), 4 deletions(-)
> >
> > diff --git a/hw/pci-host/pnv_phb4.c b/hw/pci-host/pnv_phb4.c
> > index ee046725ac..ca2f4078e5 100644
> > --- a/hw/pci-host/pnv_phb4.c
> > +++ b/hw/pci-host/pnv_phb4.c
> > @@ -1487,15 +1487,85 @@ static void pnv_phb4_instance_init(Object *obj)
> >       object_initialize_child(obj, "source", &phb->xsrc, TYPE_XIVE_SOURCE);
> >   }
> > +static PnvPhb4PecStack *pnv_phb4_get_stack(PnvChip *chip, PnvPHB4 *phb,
> > +                                           Error **errp)
> > +{
> > +    Pnv9Chip *chip9 = PNV9_CHIP(chip);
> > +    int chip_id = phb->chip_id;
> > +    int index = phb->phb_id;
> > +    int i, j;
> > +
> > +    for (i = 0; i < chip->num_pecs; i++) {
> > +        /*
> > +         * For each PEC, check the amount of stacks it supports
> > +         * and see if the given phb4 index matches a stack.
> > +         */
> > +        PnvPhb4PecState *pec = &chip9->pecs[i];
> > +
> > +        for (j = 0; j < pec->num_stacks; j++) {
> > +            if (index == pnv_phb4_pec_get_phb_id(pec, j)) {
> > +                return &pec->stacks[j];
> > +            }
> > +        }
> > +    }
> > +
> > +    error_setg(errp,
> > +               "pnv-phb4 chip-id %d index %d didn't match any existing PEC",
> > +               chip_id, index);
> > +
> > +    return NULL;
> > +}
> > +
> >   static void pnv_phb4_realize(DeviceState *dev, Error **errp)
> >   {
> >       PnvPHB4 *phb = PNV_PHB4(dev);
> >       PCIHostState *pci = PCI_HOST_BRIDGE(dev);
> >       XiveSource *xsrc = &phb->xsrc;
> > +    Error *local_err = NULL;
> >       int nr_irqs;
> >       char name[32];
> > -    assert(phb->stack);
> > +    /* User created PHB */
> > +    if (!phb->stack) {
> > +        PnvMachineState *pnv = PNV_MACHINE(qdev_get_machine());
> > +        PnvChip *chip = pnv_get_chip(pnv, phb->chip_id);
> > +        PnvPhb4PecClass *pecc;
> > +        BusState *s;
> > +
> > +        if (!chip) {
> > +            error_setg(errp, "invalid chip id: %d", phb->chip_id);
> > +            return;
> > +        }
> > +
> > +        phb->stack = pnv_phb4_get_stack(chip, phb, &local_err);
> > +        if (local_err) {
> > +            error_propagate(errp, local_err);
> > +            return;
> > +        }
> > +
> > +        /* All other phb properties but 'version' are already set */
> > +        pecc = PNV_PHB4_PEC_GET_CLASS(phb->stack->pec);
> > +        object_property_set_int(OBJECT(phb), "version", pecc->version,
> > +                                &error_fatal);
> > +
> > +        /*
> > +         * Assign stack->phb since pnv_phb4_update_regions() uses it
> > +         * to access the phb.
> > +         */
> > +        phb->stack->phb = phb;
> > +
> > +        /*
> > +         * Reparent user created devices to the chip to build
> > +         * correctly the device tree.
> > +         */
> > +        pnv_chip_parent_fixup(chip, OBJECT(phb), phb->phb_id);
> > +
> > +        s = qdev_get_parent_bus(DEVICE(chip));
> > +        if (!qdev_set_parent_bus(DEVICE(phb), s, &local_err)) {
> > +            error_propagate(errp, local_err);
> > +            return;
> > +        }
> > +    }
> >       /* Set the "big_phb" flag */
> >       phb->big_phb = phb->phb_id == 0 || phb->phb_id == 3;
> > @@ -1600,7 +1670,7 @@ static void pnv_phb4_class_init(ObjectClass *klass, void 
> > *data)
> >       dc->realize         = pnv_phb4_realize;
> >       device_class_set_props(dc, pnv_phb4_properties);
> >       set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
> > -    dc->user_creatable  = false;
> > +    dc->user_creatable  = true;
> >       xfc->notify         = pnv_phb4_xive_notify;
> >   }
> > diff --git a/hw/pci-host/pnv_phb4_pec.c b/hw/pci-host/pnv_phb4_pec.c
> > index d4c52a5d28..7fe7f1f007 100644
> > --- a/hw/pci-host/pnv_phb4_pec.c
> > +++ b/hw/pci-host/pnv_phb4_pec.c
> > @@ -19,6 +19,7 @@
> >   #include "hw/pci/pci_bus.h"
> >   #include "hw/ppc/pnv.h"
> >   #include "hw/qdev-properties.h"
> > +#include "sysemu/sysemu.h"
> >   #include <libfdt.h>
> > @@ -275,9 +276,9 @@ static const TypeInfo pnv_pec_type_info = {
> >       }
> >   };
> > -static void pnv_pec_stk_realize(DeviceState *dev, Error **errp)
> > +static void pnv_pec_stk_default_phb_realize(PnvPhb4PecStack *stack,
> > +                                            Error **errp)
> >   {
> > -    PnvPhb4PecStack *stack = PNV_PHB4_PEC_STACK(dev);
> >       PnvPhb4PecState *pec = stack->pec;
> >       PnvPhb4PecClass *pecc = PNV_PHB4_PEC_GET_CLASS(pec);
> >       int phb_id = pnv_phb4_pec_get_phb_id(pec, stack->stack_no);
> > @@ -292,11 +293,23 @@ static void pnv_pec_stk_realize(DeviceState *dev, Error 
> > **errp)
> >                               &error_fatal);
> >       object_property_set_link(OBJECT(stack->phb), "stack", OBJECT(stack),
> >                                &error_abort);
> > +
> >       if (!sysbus_realize(SYS_BUS_DEVICE(stack->phb), errp)) {
> >           return;
> >       }
> >   }
> > +static void pnv_pec_stk_realize(DeviceState *dev, Error **errp)
> > +{
> > +    PnvPhb4PecStack *stack = PNV_PHB4_PEC_STACK(dev);
> > +
> > +    if (!defaults_enabled()) {
> > +        return;
> > +    }
> > +
> > +    pnv_pec_stk_default_phb_realize(stack, errp);
> > +}
> > +
> >   static Property pnv_pec_stk_properties[] = {
> >           DEFINE_PROP_UINT32("stack-no", PnvPhb4PecStack, stack_no, 0),
> >           DEFINE_PROP_LINK("pec", PnvPhb4PecStack, pec, TYPE_PNV_PHB4_PEC,
> > diff --git a/hw/ppc/pnv.c b/hw/ppc/pnv.c
> > index fe7e67e73a..837146a2fb 100644
> > --- a/hw/ppc/pnv.c
> > +++ b/hw/ppc/pnv.c
> > @@ -1960,6 +1960,8 @@ static void pnv_machine_power9_class_init(ObjectClass 
> > *oc, void *data)
> >       pmc->compat = compat;
> >       pmc->compat_size = sizeof(compat);
> >       pmc->dt_power_mgt = pnv_dt_power_mgt;
> > +
> > +    machine_class_allow_dynamic_sysbus_dev(mc, TYPE_PNV_PHB4);
> >   }
> >   static void pnv_machine_power10_class_init(ObjectClass *oc, void *data)