Re: [PATCH 1/7] spapr, xics: Get number of servers with a XICSFabricClass method

[Cédric Le Goater]

On 03/10/2019 14:49, Greg Kurz wrote:
> On Thu, 3 Oct 2019 14:24:06 +0200
> Cédric Le Goater <address@hidden> wrote:
> 
>> On 03/10/2019 14:00, Greg Kurz wrote:
>>> The number of servers, ie. upper bound of the highest VCPU id, is
>>> currently only needed to generate the "interrupt-controller" node
>>> in the DT. Soon it will be needed to inform the XICS-on-XIVE KVM
>>> device that it can allocates less resources in the XIVE HW.
>>>
>>> Add a method to XICSFabricClass for this purpose. 
>>
>> This is sPAPR code and PowerNV does not care.
>>
> 
> Then PowerNV doesn't need to implement the method.
> 
>> why can not we simply call spapr_max_server_number(spapr) ?
>>
> 
> Because the backend shouldn't reach out to sPAPR machine
> internals. XICSFabric is the natural interface for ICS/ICP
> if they need something from the machine.

>From what I can see, xics_nr_servers() is only called by : 

  spapr_dt_xics(SpaprMachineState *spapr ...)
  xics_kvm_connect(SpaprMachineState *spapr ...)

C. 

>>
>>> Implement it
>>> for sPAPR and use it to generate the "interrupt-controller" node.
>>>
>>> Signed-off-by: Greg Kurz <address@hidden>
>>> ---
>>>  hw/intc/xics.c        |    7 +++++++
>>>  hw/intc/xics_spapr.c  |    3 ++-
>>>  hw/ppc/spapr.c        |    8 ++++++++
>>>  include/hw/ppc/xics.h |    2 ++
>>>  4 files changed, 19 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/hw/intc/xics.c b/hw/intc/xics.c
>>> index dfe7dbd254ab..f82072935266 100644
>>> --- a/hw/intc/xics.c
>>> +++ b/hw/intc/xics.c
>>> @@ -716,6 +716,13 @@ ICPState *xics_icp_get(XICSFabric *xi, int server)
>>>      return xic->icp_get(xi, server);
>>>  }
>>>  
>>> +uint32_t xics_nr_servers(XICSFabric *xi)
>>> +{
>>> +    XICSFabricClass *xic = XICS_FABRIC_GET_CLASS(xi);
>>> +
>>> +    return xic->nr_servers(xi);
>>> +}
>>> +
>>>  void ics_set_irq_type(ICSState *ics, int srcno, bool lsi)
>>>  {
>>>      assert(!(ics->irqs[srcno].flags & XICS_FLAGS_IRQ_MASK));
>>> diff --git a/hw/intc/xics_spapr.c b/hw/intc/xics_spapr.c
>>> index 6e5eb24b3cca..aa568ed0dc0d 100644
>>> --- a/hw/intc/xics_spapr.c
>>> +++ b/hw/intc/xics_spapr.c
>>> @@ -311,8 +311,9 @@ static void ics_spapr_realize(DeviceState *dev, Error 
>>> **errp)
>>>  void spapr_dt_xics(SpaprMachineState *spapr, uint32_t nr_servers, void 
>>> *fdt,
>>>                     uint32_t phandle)
>>>  {
>>> +    ICSState *ics = spapr->ics;
>>>      uint32_t interrupt_server_ranges_prop[] = {
>>> -        0, cpu_to_be32(nr_servers),
>>> +        0, cpu_to_be32(xics_nr_servers(ics->xics)),
>>>      };
>>>      int node;
>>>  
>>> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
>>> index 514a17ae74d6..b8b9796c88e4 100644
>>> --- a/hw/ppc/spapr.c
>>> +++ b/hw/ppc/spapr.c
>>> @@ -4266,6 +4266,13 @@ static ICPState *spapr_icp_get(XICSFabric *xi, int 
>>> vcpu_id)
>>>      return cpu ? spapr_cpu_state(cpu)->icp : NULL;
>>>  }
>>>  
>>> +static uint32_t spapr_nr_servers(XICSFabric *xi)
>>> +{
>>> +    SpaprMachineState *spapr = SPAPR_MACHINE(xi);
>>> +
>>> +    return spapr_max_server_number(spapr);
>>> +}
>>> +
>>>  static void spapr_pic_print_info(InterruptStatsProvider *obj,
>>>                                   Monitor *mon)
>>>  {
>>> @@ -4423,6 +4430,7 @@ static void spapr_machine_class_init(ObjectClass *oc, 
>>> void *data)
>>>      xic->ics_get = spapr_ics_get;
>>>      xic->ics_resend = spapr_ics_resend;
>>>      xic->icp_get = spapr_icp_get;
>>> +    xic->nr_servers = spapr_nr_servers;
>>>      ispc->print_info = spapr_pic_print_info;
>>>      /* Force NUMA node memory size to be a multiple of
>>>       * SPAPR_MEMORY_BLOCK_SIZE (256M) since that's the granularity
>>> diff --git a/include/hw/ppc/xics.h b/include/hw/ppc/xics.h
>>> index 1e6a9300eb2b..e6bb1239e8f8 100644
>>> --- a/include/hw/ppc/xics.h
>>> +++ b/include/hw/ppc/xics.h
>>> @@ -151,9 +151,11 @@ typedef struct XICSFabricClass {
>>>      ICSState *(*ics_get)(XICSFabric *xi, int irq);
>>>      void (*ics_resend)(XICSFabric *xi);
>>>      ICPState *(*icp_get)(XICSFabric *xi, int server);
>>> +    uint32_t (*nr_servers)(XICSFabric *xi);
>>>  } XICSFabricClass;
>>>  
>>>  ICPState *xics_icp_get(XICSFabric *xi, int server);
>>> +uint32_t xics_nr_servers(XICSFabric *xi);
>>>  
>>>  /* Internal XICS interfaces */
>>>  void icp_set_cppr(ICPState *icp, uint8_t cppr);
>>>
>>
>