Re: [PATCH v2 03/16] ppc/pnv: add PnvPHB base/proxy device

[Daniel Henrique Barboza]

On 6/2/22 13:16, Frederic Barrat wrote:
> On 31/05/2022 23:49, Daniel Henrique Barboza wrote:
> > The PnvPHB device is going to be the base device for all other powernv
> > PHBs. It consists of a device that has the same user API as the other
> > PHB, namely being a PCIHostBridge and having chip-id and index
> > properties. It also has a 'backend' pointer that will be initialized
> > with the PHB implementation that the device is going to use.
> >
> > The initialization of the PHB backend is done by checking the PHB
> > version via a 'version' attribute that can be set via a global machine
> > property.  The 'version' field will be used to make adjustments based on
> > the running version, e.g. PHB3 uses a 'chip' reference while PHB4 uses
> > 'pec'. To init the PnvPHB bus we'll rely on helpers for each version.
> > The version 3 helper is already added (pnv_phb3_bus_init), the PHB4
> > helper will be added later on.
> >
> > For now let's add the basic logic of the PnvPHB object, which consists
> > mostly of pnv_phb_realize() doing all the work of checking the
> > phb->version set, initializing the proper backend, passing through its
> > attributes to the chosen backend, finalizing the backend realize and
> > adding a root port in the end.
> >
> > Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
> > ---
> >   hw/pci-host/meson.build |   3 +-
> >   hw/pci-host/pnv_phb.c   | 123 ++++++++++++++++++++++++++++++++++++++++
> >   hw/pci-host/pnv_phb.h   |  39 +++++++++++++
> >   3 files changed, 164 insertions(+), 1 deletion(-)
> >   create mode 100644 hw/pci-host/pnv_phb.c
> >   create mode 100644 hw/pci-host/pnv_phb.h
> >
> > diff --git a/hw/pci-host/meson.build b/hw/pci-host/meson.build
> > index c07596d0d1..e832babc9d 100644
> > --- a/hw/pci-host/meson.build
> > +++ b/hw/pci-host/meson.build
> > @@ -35,5 +35,6 @@ specific_ss.add(when: 'CONFIG_PCI_POWERNV', if_true: files(
> >     'pnv_phb3_msi.c',
> >     'pnv_phb3_pbcq.c',
> >     'pnv_phb4.c',
> > -  'pnv_phb4_pec.c'
> > +  'pnv_phb4_pec.c',
> > +  'pnv_phb.c',
> >   ))
> > diff --git a/hw/pci-host/pnv_phb.c b/hw/pci-host/pnv_phb.c
> > new file mode 100644
> > index 0000000000..fa8472622f
> > --- /dev/null
> > +++ b/hw/pci-host/pnv_phb.c
> > @@ -0,0 +1,123 @@
> > +/*
> > + * QEMU PowerPC PowerNV Proxy PHB model
> > + *
> > + * Copyright (c) 2022, IBM Corporation.
> > + *
> > + * This code is licensed under the GPL version 2 or later. See the
> > + * COPYING file in the top-level directory.
> > + */
> > +
> > +#include "qemu/osdep.h"
> > +#include "qemu/log.h"
> > +#include "qapi/visitor.h"
> > +#include "qapi/error.h"
> > +#include "hw/pci-host/pnv_phb.h"
> > +#include "hw/pci-host/pnv_phb3.h"
> > +#include "hw/pci-host/pnv_phb4.h"
> > +#include "hw/ppc/pnv.h"
> > +#include "hw/qdev-properties.h"
> > +#include "qom/object.h"
> > +
> > +
> > +static void pnv_phb_realize(DeviceState *dev, Error **errp)
> > +{
> > +    PnvPHB *phb = PNV_PHB(dev);
> > +    PCIHostState *pci = PCI_HOST_BRIDGE(dev);
> > +    g_autofree char *phb_typename = NULL;
> > +    g_autofree char *phb_rootport_typename = NULL;
> > +
> > +    if (!phb->version) {
> > +        error_setg(errp, "version not specified");
> > +        return;
> > +    }
> > +
> > +    switch (phb->version) {
> > +    case 3:
> > +        phb_typename = g_strdup(TYPE_PNV_PHB3);
> > +        phb_rootport_typename = g_strdup(TYPE_PNV_PHB3_ROOT_PORT);
> > +        break;
> > +    case 4:
> > +        phb_typename = g_strdup(TYPE_PNV_PHB4);
> > +        phb_rootport_typename = g_strdup(TYPE_PNV_PHB4_ROOT_PORT);
> > +        break;
> > +    case 5:
> > +        phb_typename = g_strdup(TYPE_PNV_PHB5);
> > +        phb_rootport_typename = g_strdup(TYPE_PNV_PHB5_ROOT_PORT);
> > +        break;
> > +    default:
> > +        g_assert_not_reached();
> > +    }
> > +
> > +    phb->backend = object_new(phb_typename);
> > +    object_property_add_child(OBJECT(dev), "phb-device", phb->backend);
> > +
> > +    /* Passthrough child device properties to the proxy device */
> > +    object_property_set_uint(phb->backend, "index", phb->phb_id, errp);
> > +    object_property_set_uint(phb->backend, "chip-id", phb->chip_id, errp);
> > +    object_property_set_link(phb->backend, "phb-base", OBJECT(phb), errp);
> > +
> > +    if (phb->version == 3) {
> > +        object_property_set_link(phb->backend, "chip",
> > +                                 OBJECT(phb->chip), errp);
> > +    } else {
> > +        object_property_set_link(phb->backend, "pec", OBJECT(phb->pec), errp);
> > +    }
>
>
> The patch is fine, but it just highlights that we're doing something wrong. I 
> don't believe there's any reason for the chip/pec/phb relationship to be 
> different between P8 and P9/P10. One day, a brave soul could try to unify the 
> models, it would avoid test like that.

Not a bad idea, especially if we can cut more complexity out of the code.
I'll give it some thought.


Daniel



> It would be a good cleanup series to do if we ever extend the model with yet 
> another version :-)
>
>
>
> > +
> > +    if (!qdev_realize(DEVICE(phb->backend), NULL, errp)) {
> > +        return;
> > +    }
> > +
> > +    if (phb->version == 3) {
> > +        pnv_phb3_bus_init(dev, (PnvPHB3 *)phb->backend);
> > +    }
> > +
> > +    pnv_phb_attach_root_port(pci, phb_rootport_typename);
>
>
>
> After we've removed the other instances (done in later patches), we could move 
> pnv_phb_attach_root_port() to pnv_phb.c instead of pnv.c. It would be the 
> perfect home for it as it starts looking off in pnv.c
>
>    Fred
>
>
>
> > +}
> > +
> > +static const char *pnv_phb_root_bus_path(PCIHostState *host_bridge,
> > +                                         PCIBus *rootbus)
> > +{
> > +    PnvPHB *phb = PNV_PHB(host_bridge);
> > +
> > +    snprintf(phb->bus_path, sizeof(phb->bus_path), "00%02x:%02x",
> > +             phb->chip_id, phb->phb_id);
> > +    return phb->bus_path;
> > +}
> > +
> > +static Property pnv_phb_properties[] = {
> > +        DEFINE_PROP_UINT32("index", PnvPHB, phb_id, 0),
> > +        DEFINE_PROP_UINT32("chip-id", PnvPHB, chip_id, 0),
> > +        DEFINE_PROP_UINT32("version", PnvPHB, version, 0),
> > +
> > +        DEFINE_PROP_LINK("chip", PnvPHB, chip, TYPE_PNV_CHIP, PnvChip *),
> > +
> > +        DEFINE_PROP_LINK("pec", PnvPHB, pec, TYPE_PNV_PHB4_PEC,
> > +                         PnvPhb4PecState *),
> > +
> > +        DEFINE_PROP_END_OF_LIST(),
> > +};
> > +
> > +static void pnv_phb_class_init(ObjectClass *klass, void *data)
> > +{
> > +    PCIHostBridgeClass *hc = PCI_HOST_BRIDGE_CLASS(klass);
> > +    DeviceClass *dc = DEVICE_CLASS(klass);
> > +
> > +    hc->root_bus_path = pnv_phb_root_bus_path;
> > +    dc->realize = pnv_phb_realize;
> > +    device_class_set_props(dc, pnv_phb_properties);
> > +    set_bit(DEVICE_CATEGORY_BRIDGE, dc->categories);
> > +    dc->user_creatable = true;
> > +}
> > +
> > +static void pnv_phb_register_type(void)
> > +{
> > +    static const TypeInfo pnv_phb_type_info = {
> > +        .name          = TYPE_PNV_PHB,
> > +        .parent        = TYPE_PCIE_HOST_BRIDGE,
> > +        .instance_size = sizeof(PnvPHB),
> > +        .class_init    = pnv_phb_class_init,
> > +    };
> > +
> > +    type_register_static(&pnv_phb_type_info);
> > +}
> > +type_init(pnv_phb_register_type)
> > diff --git a/hw/pci-host/pnv_phb.h b/hw/pci-host/pnv_phb.h
> > new file mode 100644
> > index 0000000000..a7cc8610e2
> > --- /dev/null
> > +++ b/hw/pci-host/pnv_phb.h
> > @@ -0,0 +1,39 @@
> > +/*
> > + * QEMU PowerPC PowerNV Proxy PHB model
> > + *
> > + * Copyright (c) 2022, IBM Corporation.
> > + *
> > + * This code is licensed under the GPL version 2 or later. See the
> > + * COPYING file in the top-level directory.
> > + */
> > +
> > +#ifndef PCI_HOST_PNV_PHB_H
> > +#define PCI_HOST_PNV_PHB_H
> > +
> > +#include "hw/pci/pcie_host.h"
> > +#include "hw/pci/pcie_port.h"
> > +#include "qom/object.h"
> > +
> > +typedef struct PnvChip PnvChip;
> > +typedef struct PnvPhb4PecState PnvPhb4PecState;
> > +
> > +struct PnvPHB {
> > +    PCIExpressHost parent_obj;
> > +
> > +    uint32_t chip_id;
> > +    uint32_t phb_id;
> > +    uint32_t version;
> > +    char bus_path[8];
> > +
> > +    PnvChip *chip;
> > +
> > +    PnvPhb4PecState *pec;
> > +
> > +    /* The PHB backend (PnvPHB3, PnvPHB4 ...) being used */
> > +    Object *backend;
> > +};
> > +
> > +#define TYPE_PNV_PHB "pnv-phb"
> > +OBJECT_DECLARE_SIMPLE_TYPE(PnvPHB, PNV_PHB)
> > +
> > +#endif /* PCI_HOST_PNV_PHB_H */