Re: [Qemu-devel] [PATCH 15/15] spapr: add hotplug hooks for PHB hotplug

[David Gibson <david@gibson.dropbear.id.au>]

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On Fri, Dec 21, 2018 at 07:36:12AM +0100, Greg Kurz wrote:
> From: Michael Roth <mdroth@linux.vnet.ibm.com>
> 
> Hotplugging PHBs is a machine-level operation, but PHBs reside on the
> main system bus, so we register spapr machine as the handler for the
> main system bus.
> 
> We re-get the phandle of the interrupt controller systematically for
> simplicity.
> 
> Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>
> Signed-off-by: Greg Kurz <groug@kaod.org>
> ---
>  hw/ppc/spapr.c         |  147 ++++++++++++++++++++++++++++++++++++++++++++++++
>  hw/ppc/spapr_drc.c     |    1 
>  hw/ppc/spapr_pci.c     |   16 -----
>  include/hw/ppc/spapr.h |    1 
>  4 files changed, 149 insertions(+), 16 deletions(-)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 5c405a5fafca..065c9f19700e 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -2923,6 +2923,10 @@ static void spapr_machine_init(MachineState *machine)
>      register_savevm_live(NULL, "spapr/htab", -1, 1,
>                           &savevm_htab_handlers, spapr);
>  
> +    if (smc->dr_phb_enabled) {
> +        qbus_set_hotplug_handler(sysbus_get_default(), OBJECT(machine), NULL);
> +    }
> +
>      qemu_register_boot_set(spapr_boot_set, spapr);
>  
>      if (kvm_enabled()) {
> @@ -3716,6 +3720,135 @@ out:
>      error_propagate(errp, local_err);
>  }
>  
> +static void spapr_phb_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
> +                               Error **errp)
> +{
> +    sPAPRMachineState *spapr = SPAPR_MACHINE(OBJECT(hotplug_dev));
> +    sPAPRPHBState *sphb = SPAPR_PCI_HOST_BRIDGE(dev);
> +    sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(spapr);
> +    const unsigned windows_supported = spapr_phb_windows_supported(sphb);
> +
> +    if (sphb->index == (uint32_t)-1) {
> +        error_setg(errp, "\"index\" for PAPR PHB is mandatory");
> +        return;
> +    }
> +
> +    /*
> +     * This will check that sphb->index doesn't exceed the maximum number of
> +     * PHBs for the current machine type.
> +     */
> +    smc->phb_placement(spapr, sphb->index,
> +                       &sphb->buid, &sphb->io_win_addr,
> +                       &sphb->mem_win_addr, &sphb->mem64_win_addr,
> +                       windows_supported, sphb->dma_liobn, errp);
> +}
> +
> +static void spapr_phb_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
> +                           Error **errp)
> +{
> +    sPAPRMachineState *spapr = SPAPR_MACHINE(OBJECT(hotplug_dev));
> +    sPAPRMachineClass *smc = SPAPR_MACHINE_GET_CLASS(spapr);
> +    sPAPRPHBState *sphb = SPAPR_PCI_HOST_BRIDGE(dev);
> +    void *fdt = NULL;
> +    int fdt_start_offset;
> +    int fdt_size;
> +    Error *local_err = NULL;
> +    sPAPRDRConnector *drc;
> +    int ret;
> +    bool hotplugged = spapr_drc_hotplugged(dev);
> +    int offset, phandle = 0;
> +    gchar *nodename = NULL;
> +
> +    if (!smc->dr_phb_enabled) {
> +        return;
> +    }
> +
> +    drc = spapr_drc_by_id(TYPE_SPAPR_DRC_PHB, sphb->index);
> +    /* hotplug hooks should check it's enabled before getting this far */
> +    assert(drc);
> +
> +    if (hotplugged) {
> +        if (spapr->fdt_blob) {
> +            /*
> +             * SLOF might have pushed an updated FDT with new phandle values.
> +             * Re-get the one of our interrupt controller.
> +             */
> +            nodename = spapr->irq->get_nodename(spapr);
> +
> +            offset = fdt_subnode_offset(spapr->fdt_blob, 0, nodename);
> +            if (offset < 0) {
> +                error_setg(errp, "Can't find node \"%s\": %s",
> +                           nodename, fdt_strerror(offset));
> +                goto out;
> +            }
> +
> +            phandle = fdt_get_phandle(spapr->fdt_blob, offset);
> +            if (phandle < 0) {
> +                error_setg(errp, "Can't get phandle of node \"%s\": %s",
> +                           nodename, fdt_strerror(offset));
> +                goto out;
> +            }
> +        }
> +        DEVICE_GET_CLASS(dev)->reset(dev);
> +    }
> +
> +    /* For cold-plugged at initial boot and fallback for hotplug */
> +    if (!phandle) {
> +        phandle = PHANDLE_XICP;
> +    }
> +
> +    fdt = create_device_tree(&fdt_size);
> +    ret = spapr_populate_pci_dt(sphb, phandle, fdt, spapr->irq->nr_msis,
> +                                &fdt_start_offset);
> +    if (ret < 0) {
> +        error_setg(&local_err, "unable to create FDT for %sPHB",
> +                   dev->hotplugged ? "hotplugged " : "");
> +        goto out;
> +    }
> +
> +    if (hotplugged) {
> +        /* generally SLOF creates these, for hotplug it's up to QEMU */
> +        _FDT(fdt_setprop_string(fdt, fdt_start_offset, "name", "pci"));
> +    }
> +
> +    spapr_drc_attach(drc, DEVICE(dev), fdt, fdt_start_offset, &local_err);
> +
> +out:
> +    g_free(nodename);
> +
> +    if (local_err) {
> +        error_propagate(errp, local_err);
> +        g_free(fdt);
> +        return;
> +    }
> +
> +    if (hotplugged) {
> +        spapr_hotplug_req_add_by_index(drc);
> +    } else if (drc) {
> +        spapr_drc_reset(drc);
> +    }
> +}
> +
> +void spapr_phb_release(DeviceState *dev)
> +{
> +    object_unparent(OBJECT(dev));
> +}
> +
> +static void spapr_phb_unplug_request(HotplugHandler *hotplug_dev,
> +                                     DeviceState *dev, Error **errp)
> +{
> +    sPAPRPHBState *sphb = SPAPR_PCI_HOST_BRIDGE(dev);
> +    sPAPRDRConnector *drc;
> +
> +    drc = spapr_drc_by_id(TYPE_SPAPR_DRC_PHB, sphb->index);
> +    assert(drc);
> +
> +    if (!spapr_drc_unplug_requested(drc)) {
> +        spapr_drc_detach(drc);
> +        spapr_hotplug_req_remove_by_index(drc);
> +    }
> +}
> +
>  static void spapr_machine_device_plug(HotplugHandler *hotplug_dev,
>                                        DeviceState *dev, Error **errp)
>  {
> @@ -3723,6 +3856,8 @@ static void spapr_machine_device_plug(HotplugHandler *hotplug_dev,
>          spapr_memory_plug(hotplug_dev, dev, errp);
>      } else if (object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_CPU_CORE)) {
>          spapr_core_plug(hotplug_dev, dev, errp);
> +    } else if (object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_PCI_HOST_BRIDGE)) {
> +        spapr_phb_plug(hotplug_dev, dev, errp);
>      }
>  }
>  
> @@ -3741,6 +3876,7 @@ static void spapr_machine_device_unplug_request(HotplugHandler *hotplug_dev,
>  {
>      sPAPRMachineState *sms = SPAPR_MACHINE(OBJECT(hotplug_dev));
>      MachineClass *mc = MACHINE_GET_CLASS(sms);
> +    sPAPRMachineClass *smc = SPAPR_MACHINE_CLASS(mc);
>  
>      if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM)) {
>          if (spapr_ovec_test(sms->ov5_cas, OV5_HP_EVT)) {
> @@ -3760,6 +3896,12 @@ static void spapr_machine_device_unplug_request(HotplugHandler *hotplug_dev,
>              return;
>          }
>          spapr_core_unplug_request(hotplug_dev, dev, errp);
> +    } else if (object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_PCI_HOST_BRIDGE)) {
> +        if (!smc->dr_phb_enabled) {
> +            error_setg(errp, "PHB hot unplug not supported on this machine");
> +            return;
> +        }
> +        spapr_phb_unplug_request(hotplug_dev, dev, errp);
>      }
>  }
>  
> @@ -3770,6 +3912,8 @@ static void spapr_machine_device_pre_plug(HotplugHandler *hotplug_dev,
>          spapr_memory_pre_plug(hotplug_dev, dev, errp);
>      } else if (object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_CPU_CORE)) {
>          spapr_core_pre_plug(hotplug_dev, dev, errp);
> +    } else if (object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_PCI_HOST_BRIDGE)) {
> +        spapr_phb_pre_plug(hotplug_dev, dev, errp);
>      }
>  }
>  
> @@ -3777,7 +3921,8 @@ static HotplugHandler *spapr_get_hotplug_handler(MachineState *machine,
>                                                   DeviceState *dev)
>  {
>      if (object_dynamic_cast(OBJECT(dev), TYPE_PC_DIMM) ||
> -        object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_CPU_CORE)) {
> +        object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_CPU_CORE) ||
> +        object_dynamic_cast(OBJECT(dev), TYPE_SPAPR_PCI_HOST_BRIDGE)) {
>          return HOTPLUG_HANDLER(machine);
>      }
>      return NULL;
> diff --git a/hw/ppc/spapr_drc.c b/hw/ppc/spapr_drc.c
> index 189ee681062a..7a2676716364 100644
> --- a/hw/ppc/spapr_drc.c
> +++ b/hw/ppc/spapr_drc.c
> @@ -703,6 +703,7 @@ static void spapr_drc_phb_class_init(ObjectClass *k, void *data)
>      drck->typeshift = SPAPR_DR_CONNECTOR_TYPE_SHIFT_PHB;
>      drck->typename = "PHB";
>      drck->drc_name_prefix = "PHB ";
> +    drck->release = spapr_phb_release;
>  }
>  
>  static const TypeInfo spapr_dr_connector_info = {
> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
> index 688cca83ef2f..5bc912aa0028 100644
> --- a/hw/ppc/spapr_pci.c
> +++ b/hw/ppc/spapr_pci.c
> @@ -1627,21 +1627,7 @@ static void spapr_phb_realize(DeviceState *dev, Error **errp)
>          return;
>      }
>  
> -    if (sphb->index != (uint32_t)-1) {
> -        Error *local_err = NULL;
> -
> -        smc->phb_placement(spapr, sphb->index,
> -                           &sphb->buid, &sphb->io_win_addr,
> -                           &sphb->mem_win_addr, &sphb->mem64_win_addr,
> -                           windows_supported, sphb->dma_liobn, &local_err);
> -        if (local_err) {
> -            error_propagate(errp, local_err);
> -            return;
> -        }
> -    } else {
> -        error_setg(errp, "\"index\" for PAPR PHB is mandatory");
> -        return;
> -    }
> +    assert(sphb->index != (uint32_t)-1); /* checked in spapr_phb_pre_plug() */

Could this cause an unexpected assert if you're using an older machine
type that doesn't install the hotplug handler, then don't supply an
index on the command line?

>      if (sphb->mem64_win_size != 0) {
>          if (sphb->mem_win_size > SPAPR_PCI_MEM32_WIN_SIZE) {
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index e96deefa30de..eff479b0a019 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -764,6 +764,7 @@ int spapr_max_server_number(sPAPRMachineState *spapr);
>  /* CPU and LMB DRC release callbacks. */
>  void spapr_core_release(DeviceState *dev);
>  void spapr_lmb_release(DeviceState *dev);
> +void spapr_phb_release(DeviceState *dev);
>  
>  void spapr_rtc_read(sPAPRRTCState *rtc, struct tm *tm, uint32_t *ns);
>  int spapr_rtc_import_offset(sPAPRRTCState *rtc, int64_t legacy_offset);
> 

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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