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

From: Daniel Henrique Barboza <danielhb413@gmail.com>
To: Frederic Barrat <fbarrat@linux.ibm.com>, qemu-devel@nongnu.org
Cc: qemu-ppc@nongnu.org, david@gibson.dropbear.id.au, clg@kaod.org,
	mark.cave-ayland@ilande.co.uk
Subject: Re: [PATCH v2 03/16] ppc/pnv: add PnvPHB base/proxy device
Date: Thu, 2 Jun 2022 17:55:05 -0300	[thread overview]
Message-ID: <cf61c578-1188-8a94-fdab-6baeb646012d@gmail.com> (raw)
In-Reply-To: <fd2aa961-6f79-3628-ef3c-f22ac23e5052@linux.ibm.com>

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 */