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

[Greg Kurz <groug@kaod.org>]

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On Thu, 27 Jul 2017 14:41:31 +1000
Alexey Kardashevskiy <aik@ozlabs.ru> wrote:

> 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 <mdroth@linux.vnet.ibm.com>
> > Signed-off-by: Greg Kurz <groug@kaod.org>
> > ---
> > - 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).

You're right and this looks like a bug... I'll try to come up with a fix.

> May be just ditch drc_id, enforce index not to be -1 and use it as drc_id?
> 

This was how Mike did it in the original patchset but David suggested
to introduce drc_id (to preserve existing setups I guess):

http://patchwork.ozlabs.org/patch/466262/

> 
> 
> > +}
> > +
> > +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);
> > 
> >   
> 
> 


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