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

[Greg Kurz <groug@kaod.org>]

On Thu, 3 Oct 2019 14:58:45 +0200
Cédric Le Goater <clg@kaod.org> wrote:

> On 03/10/2019 14:49, Greg Kurz wrote:
> > On Thu, 3 Oct 2019 14:24:06 +0200
> > Cédric Le Goater <clg@kaod.org> 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 ...)
> 

Yes... and ?

> C. 
> 
> >>
> >>> Implement it
> >>> for sPAPR and use it to generate the "interrupt-controller" node.
> >>>
> >>> Signed-off-by: Greg Kurz <groug@kaod.org>
> >>> ---
> >>>  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);
> >>>
> >>
> > 
>