Re: [Qemu-devel] [for-2.11 PATCH 26/26] spapr: add hotplug hooks for PHB hotplug

[Alexey Kardashevskiy]

On 26/07/17 18:40, Greg Kurz wrote:
> 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.
> 
> Signed-off-by: Michael Roth <address@hidden>
> Signed-off-by: Greg Kurz <address@hidden>
> ---
> - rebased against ppc-for-2.10
> - converted to unplug_request
> - handle drc_id at pre-plug
> - reset hotplugged PHB at plug
> - compatibility with older machine types
> ---
>  hw/ppc/spapr.c              |  114 
> +++++++++++++++++++++++++++++++++++++++++++
>  hw/ppc/spapr_drc.c          |    1 
>  hw/ppc/spapr_pci.c          |    2 -
>  include/hw/pci-host/spapr.h |    2 +
>  include/hw/ppc/spapr.h      |    1 
>  5 files changed, 118 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 90485054c2e7..589f76ef9fb8 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -2540,6 +2540,10 @@ static void ppc_spapr_init(MachineState *machine)
>      register_savevm_live(NULL, "spapr/htab", -1, 1,
>                           &savevm_htab_handlers, spapr);
>  
> +    if (spapr->dr_phb_enabled) {
> +        qbus_set_hotplug_handler(sysbus_get_default(), OBJECT(machine), 
> NULL);
> +    }
> +
>      qemu_register_boot_set(spapr_boot_set, spapr);
>  
>      if (kvm_enabled()) {
> @@ -3238,6 +3242,103 @@ out:
>      error_propagate(errp, local_err);
>  }
>  
> +static void spapr_phb_pre_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
> +                               Error **errp)
> +{
> +    sPAPRPHBState *sphb = SPAPR_PCI_HOST_BRIDGE(dev);
> +
> +    if (sphb->drc_id == (uint32_t)-1) {
> +        sphb->drc_id = sphb->index;
> +    }
> +
> +    if (sphb->drc_id >= SPAPR_DRC_MAX_PHB) {
> +        error_setg(errp, "PHB id %d out of range", sphb->drc_id);
> +    }


sphb->index in considered 16bits in the existing code (even though it is
defined as 32bit) and SPAPR_DRC_MAX_PHB is just 256. I'd suggest using the
same limit for both, either 256 or 65536 is fine for me.

It is actually a bit weird - it is possible to completely configure few
PHBs in the command line so they will have index==-1 but PCI hotplug code -
spapr_phb_get_pci_func_drc() and spapr_phb_realize() - does not check for
this and just does (sphb->index << 16). May be just ditch drc_id, enforce
index not to be -1 and use it as drc_id?



> +}
> +
> +static void spapr_phb_plug(HotplugHandler *hotplug_dev, DeviceState *dev,
> +                           Error **errp)
> +{
> +    sPAPRMachineState *spapr = SPAPR_MACHINE(OBJECT(hotplug_dev));
> +    sPAPRPHBState *sphb = SPAPR_PCI_HOST_BRIDGE(dev);
> +    void *fdt = NULL;
> +    int fdt_start_offset;
> +    int fdt_size;
> +    Error *local_err = NULL;
> +    sPAPRDRConnector *drc;
> +    uint32_t phandle;
> +    int ret;
> +    bool hotplugged = spapr_drc_hotplugged(dev);
> +
> +    if (!spapr->dr_phb_enabled) {
> +        return;
> +    }
> +
> +    drc = spapr_drc_by_id(TYPE_SPAPR_DRC_PHB, sphb->drc_id);
> +    /* hotplug hooks should check it's enabled before getting this far */
> +    g_assert(drc);
> +
> +    if (hotplugged) {
> +        if (spapr->xics_phandle == UINT32_MAX) {
> +            error_setg(&local_err,
> +                       "SLOF didn't update the XICS phandle. PHB hotplug 
> cancelled");
> +            goto out;
> +        }
> +        phandle = spapr->xics_phandle;
> +
> +        spapr_phb_reset(dev);


It could be DEVICE_GET_CLASS(dev)->reset(dev) without exporting
spapr_phb_reset. Not sure how this fits into the current QEMU coding style
though.



> +    } else {
> +        phandle = PHANDLE_XICP;
> +    }
> +
> +    fdt = create_device_tree(&fdt_size);
> +    ret = spapr_populate_pci_dt(sphb, phandle, fdt, &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:
> +    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->drc_id);
> +    g_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)
>  {
> @@ -3284,6 +3385,8 @@ static void spapr_machine_device_plug(HotplugHandler 
> *hotplug_dev,
>          spapr_memory_plug(hotplug_dev, dev, node, 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);
>      }
>  }
>  
> @@ -3311,6 +3414,12 @@ 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 (sms->dr_phb_enabled) {
> +            spapr_phb_unplug_request(hotplug_dev, dev, errp);
> +        } else {
> +            error_setg(errp, "PHB hot unplug not supported on this machine");
> +        }
>      }
>  }
>  
> @@ -3321,6 +3430,8 @@ 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);
>      }
>  }
>  
> @@ -3328,7 +3439,8 @@ 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 2e1049ce61c7..845fcf70b932 100644
> --- a/hw/ppc/spapr_drc.c
> +++ b/hw/ppc/spapr_drc.c
> @@ -704,6 +704,7 @@ 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 157867af8178..c12f71ae3e2d 100644
> --- a/hw/ppc/spapr_pci.c
> +++ b/hw/ppc/spapr_pci.c
> @@ -1833,7 +1833,7 @@ void spapr_phb_dma_reset(sPAPRPHBState *sphb)
>                             sphb->dma_win_size >> SPAPR_TCE_PAGE_SHIFT);
>  }
>  
> -static void spapr_phb_reset(DeviceState *qdev)
> +void spapr_phb_reset(DeviceState *qdev)
>  {
>      sPAPRPHBState *sphb = SPAPR_PCI_HOST_BRIDGE(qdev);
>  
> diff --git a/include/hw/pci-host/spapr.h b/include/hw/pci-host/spapr.h
> index 7837fb0b1110..15799cee4280 100644
> --- a/include/hw/pci-host/spapr.h
> +++ b/include/hw/pci-host/spapr.h
> @@ -120,6 +120,8 @@ int spapr_populate_pci_dt(sPAPRPHBState *phb,
>  
>  void spapr_pci_rtas_init(void);
>  
> +void spapr_phb_reset(DeviceState *qdev);
> +
>  sPAPRPHBState *spapr_pci_find_phb(sPAPRMachineState *spapr, uint64_t buid);
>  PCIDevice *spapr_pci_find_dev(sPAPRMachineState *spapr, uint64_t buid,
>                                uint32_t config_addr);
> diff --git a/include/hw/ppc/spapr.h b/include/hw/ppc/spapr.h
> index f09c54d5bb94..a2f6782bdbbf 100644
> --- a/include/hw/ppc/spapr.h
> +++ b/include/hw/ppc/spapr.h
> @@ -673,6 +673,7 @@ void spapr_reallocate_hpt(sPAPRMachineState *spapr, int 
> shift,
>  /* 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);
> 
> 


-- 
Alexey