Re: [Qemu-devel] [PATCH RFC V2 12/17] hw/pci: introduce PCI Expander Bridge (PXB)

[Alexander Graf <agraf@suse.de>]

On 16.02.15 10:54, Marcel Apfelbaum wrote:
> From: Marcel Apfelbaum <marcel.a@redhat.com>
> 
> PXB is a "light-weight" host bridge whose purpose is to enable
> the main host bridge to support multiple PCI root buses.
> 
> As oposed to PCI-2-PCI bridge's secondary bus, PXB's bus
> is a primary bus and can be associated with a NUMA node
> (different from the main host bridge) allowing the guest OS
> to recognize the proximity of a pass-through device to
> other resources as RAM and CPUs.
> 
> The PXB is composed from:
>  - A primary PCI bus (can be associated with a NUMA node)
>    Acts like a normal pci bus and from the functionality point
>    of view is an "expansion" of the bus behind the
>    main host bridge.
>  - A pci-2-pci bridge behind the primary PCI bus where the actual
>    devices will be attached.
>  - A host-bridge PCI device
>    Situated on the bus behind the main host bridge, allows
>    the BIOS to configure the bus number and IO/mem resources.
>    It does not have its own config/data register for configuration
>    cycles, this being handled by the main host bridge.
> -  A host-bridge sysbus to comply with QEMU current design.
> 
> Signed-off-by: Marcel Apfelbaum <marcel@redhat.com>
> ---
>  hw/pci-bridge/Makefile.objs         |   1 +
>  hw/pci-bridge/pci_expander_bridge.c | 173 ++++++++++++++++++++++++++++++++++++
>  include/hw/pci/pci.h                |   1 +
>  3 files changed, 175 insertions(+)
>  create mode 100644 hw/pci-bridge/pci_expander_bridge.c
> 
> diff --git a/hw/pci-bridge/Makefile.objs b/hw/pci-bridge/Makefile.objs
> index 968b369..632e442 100644
> --- a/hw/pci-bridge/Makefile.objs
> +++ b/hw/pci-bridge/Makefile.objs
> @@ -1,4 +1,5 @@
>  common-obj-y += pci_bridge_dev.o
> +common-obj-y += pci_expander_bridge.o
>  common-obj-y += ioh3420.o xio3130_upstream.o xio3130_downstream.o
>  common-obj-y += i82801b11.o
>  # NewWorld PowerMac
> diff --git a/hw/pci-bridge/pci_expander_bridge.c b/hw/pci-bridge/pci_expander_bridge.c
> new file mode 100644
> index 0000000..941f3c8
> --- /dev/null
> +++ b/hw/pci-bridge/pci_expander_bridge.c
> @@ -0,0 +1,173 @@
> +/*
> + * PCI Expander Bridge Device Emulation
> + *
> + * Copyright (C) 2014 Red Hat Inc
> + *
> + * Authors:
> + *   Marcel Apfelbaum <marcel.a@redhat.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or later.
> + * See the COPYING file in the top-level directory.
> + */
> +
> +#include "hw/pci/pci.h"
> +#include "hw/pci/pci_bus.h"
> +#include "hw/pci/pci_host.h"
> +#include "hw/pci/pci_bus.h"
> +#include "qemu/range.h"
> +#include "qemu/error-report.h"
> +
> +#define TYPE_PXB_BUS "pxb-bus"
> +#define PXB_BUS(obj) OBJECT_CHECK(PXBBus, (obj), TYPE_PXB_BUS)
> +
> +typedef struct PXBBus {
> +    /*< private >*/
> +    PCIBus parent_obj;
> +    /*< public >*/
> +
> +    char bus_path[8];
> +} PXBBus;
> +
> +#define TYPE_PXB_DEVICE "pxb-device"
> +#define PXB_DEV(obj) OBJECT_CHECK(PXBDev, (obj), TYPE_PXB_DEVICE)
> +
> +typedef struct PXBDev {
> +    /*< private >*/
> +    PCIDevice parent_obj;
> +    /*< public >*/
> +
> +    uint8_t bus_nr;
> +} PXBDev;
> +
> +#define TYPE_PXB_HOST "pxb-host"
> +
> +static int pxb_bus_num(PCIBus *bus)
> +{
> +    PXBDev *pxb = PXB_DEV(bus->parent_dev);
> +
> +    return pxb->bus_nr;
> +}
> +
> +static bool pxb_is_root(PCIBus *bus)
> +{
> +    return true; /* by definition */
> +}
> +
> +static void pxb_bus_class_init(ObjectClass *class, void *data)
> +{
> +    PCIBusClass *pbc = PCI_BUS_CLASS(class);
> +
> +    pbc->bus_num = pxb_bus_num;
> +    pbc->is_root = pxb_is_root;
> +}
> +
> +static const TypeInfo pxb_bus_info = {
> +    .name          = TYPE_PXB_BUS,
> +    .parent        = TYPE_PCI_BUS,
> +    .instance_size = sizeof(PXBBus),
> +    .class_init    = pxb_bus_class_init,
> +};
> +
> +static const char *pxb_host_root_bus_path(PCIHostState *host_bridge,
> +                                          PCIBus *rootbus)
> +{
> +    PXBBus *bus = PXB_BUS(rootbus);
> +
> +    snprintf(bus->bus_path, 8, "0000:%02x", pxb_bus_num(rootbus));
> +    return bus->bus_path;
> +}
> +
> +static void pxb_host_class_init(ObjectClass *class, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(class);
> +    PCIHostBridgeClass *hc = PCI_HOST_BRIDGE_CLASS(class);
> +
> +    dc->fw_name = "pci";
> +    hc->root_bus_path = pxb_host_root_bus_path;
> +}
> +
> +static const TypeInfo pxb_host_info = {
> +    .name          = TYPE_PXB_HOST,
> +    .parent        = TYPE_PCI_HOST_BRIDGE,
> +    .class_init    = pxb_host_class_init,
> +};
> +
> +static int pxb_dev_initfn(PCIDevice *dev)
> +{
> +    PXBDev *pxb = PXB_DEV(dev);
> +    DeviceState *ds, *bds;
> +    PCIHostState *phs;
> +    PCIBus *bus;
> +    const char *dev_name = NULL;
> +
> +    HOST_BRIDGE_FOREACH(phs) {
> +        if (pxb->bus_nr == pci_bus_num(phs->bus)) {
> +            error_report("Bus nr %d is already used by %s.",
> +                         pxb->bus_nr, phs->bus->qbus.name);
> +            return -EINVAL;
> +        }
> +    }
> +
> +    if (dev->qdev.id && *dev->qdev.id) {
> +        dev_name = dev->qdev.id;
> +    }
> +
> +    ds = qdev_create(NULL, TYPE_PXB_HOST);
> +    bus = pci_bus_new(ds, "pxb-internal", NULL, NULL, 0, TYPE_PXB_BUS);
> +
> +    bus->parent_dev = dev;
> +    bus->address_space_mem = dev->bus->address_space_mem;
> +    bus->address_space_io = dev->bus->address_space_io;
> +    bus->map_irq = pci_swizzle_map_irq_fn;
> +
> +    bds = qdev_create(BUS(bus), "pci-bridge");
> +    bds->id = dev_name;
> +    qdev_prop_set_uint8(bds, "chassis_nr", pxb->bus_nr);
> +
> +    PCI_HOST_BRIDGE(ds)->bus = bus;
> +
> +    qdev_init_nofail(ds);
> +    qdev_init_nofail(bds);
> +
> +    pci_word_test_and_set_mask(dev->config + PCI_STATUS,
> +                               PCI_STATUS_66MHZ | PCI_STATUS_FAST_BACK);
> +    pci_config_set_class(dev->config, PCI_CLASS_BRIDGE_HOST);
> +
> +    return 0;
> +}
> +
> +static Property pxb_dev_properties[] = {
> +    /* Note: 0 is not a legal a PXB bus number. */
> +    DEFINE_PROP_UINT8("bus_nr", PXBDev, bus_nr, 0),
> +    DEFINE_PROP_END_OF_LIST(),
> +};
> +
> +static void pxb_dev_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +    PCIDeviceClass *k = PCI_DEVICE_CLASS(klass);
> +
> +    k->init = pxb_dev_initfn;
> +    k->vendor_id = PCI_VENDOR_ID_REDHAT;
> +    k->device_id = PCI_DEVICE_ID_REDHAT_PXB;
> +    k->class_id = PCI_CLASS_BRIDGE_HOST;
> +
> +    dc->desc = "PCI Expander Bridge";
> +    dc->props = pxb_dev_properties;
> +}
> +
> +static const TypeInfo pxb_dev_info = {
> +    .name          = TYPE_PXB_DEVICE,
> +    .parent        = TYPE_PCI_DEVICE,
> +    .instance_size = sizeof(PXBDev),
> +    .class_init    = pxb_dev_class_init,
> +};
> +
> +static void pxb_register_types(void)
> +{
> +    type_register_static(&pxb_bus_info);
> +    type_register_static(&pxb_host_info);
> +    type_register_static(&pxb_dev_info);
> +}
> +
> +type_init(pxb_register_types)
> diff --git a/include/hw/pci/pci.h b/include/hw/pci/pci.h
> index b7e24d4..e936528 100644
> --- a/include/hw/pci/pci.h
> +++ b/include/hw/pci/pci.h
> @@ -89,6 +89,7 @@
>  #define PCI_DEVICE_ID_REDHAT_SERIAL4     0x0004
>  #define PCI_DEVICE_ID_REDHAT_TEST        0x0005
>  #define PCI_DEVICE_ID_REDHAT_SDHCI       0x0007
> +#define PCI_DEVICE_ID_REDHAT_PXB         0x0008

This collides with the new PCI root device that should be in the tree by
now :).


Alex