Re: [Qemu-devel] [PATCH for-2.12 v3 03/11] spapr: introduce new XICSFabric operations for an IRQ allocator

[Greg Kurz]

On Fri, 10 Nov 2017 15:20:09 +0000
Cédric Le Goater <address@hidden> wrote:

> Currently, the ICSState 'ics' object of the sPAPR machine acts as the
> global interrupt source handler and also as the IRQ number allocator
> for the machine. Some IRQ numbers are allocated very early in the
> machine initialization sequence to populate the device tree, and this
> is a problem to introduce the new POWER XIVE interrupt model, as it
> needs to share the IRQ numbers with the older model.
> 
> To prepare ground for XIVE, here is a set of new XICSFabric operations
> to let the machine handle directly the IRQ number allocation and to
> decorrelate the allocation from the interrupt source object :
> 
>     bool (*irq_test)(XICSFabric *xi, int irq);
>     int (*irq_alloc_block)(XICSFabric *xi, int count, int align);
>     void (*irq_free_block)(XICSFabric *xi, int irq, int num);
> 
> In these prototypes, the 'irq' parameter refers to a number in the
> global IRQ number space. Indexes for arrays storing different state
> informations on the interrupts, like the ICSIRQState, are usually
> named 'srcno'.
> 
> Signed-off-by: Cédric Le Goater <address@hidden>
> ---

Reviewed-by: Greg Kurz <address@hidden>

>  hw/ppc/spapr.c        | 19 +++++++++++++++++++
>  include/hw/ppc/xics.h |  4 ++++
>  2 files changed, 23 insertions(+)
> 
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index a2dcbee07214..84d68f2fdbae 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -3536,6 +3536,21 @@ static ICPState *spapr_icp_get(XICSFabric *xi, int 
> vcpu_id)
>      return cpu ? ICP(cpu->intc) : NULL;
>  }
>  
> +static bool spapr_irq_test(XICSFabric *xi, int irq)
> +{
> +    return false;
> +}
> +
> +static int spapr_irq_alloc_block(XICSFabric *xi, int count, int align)
> +{
> +    return -1;
> +}
> +
> +static void spapr_irq_free_block(XICSFabric *xi, int irq, int num)
> +{
> +    ;
> +}
> +
>  static void spapr_pic_print_info(InterruptStatsProvider *obj,
>                                   Monitor *mon)
>  {
> @@ -3630,6 +3645,10 @@ 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->irq_test = spapr_irq_test;
> +    xic->irq_alloc_block = spapr_irq_alloc_block;
> +    xic->irq_free_block = spapr_irq_free_block;
> +
>      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 28d248abad61..30e7f2e0a7dd 100644
> --- a/include/hw/ppc/xics.h
> +++ b/include/hw/ppc/xics.h
> @@ -175,6 +175,10 @@ typedef struct XICSFabricClass {
>      ICSState *(*ics_get)(XICSFabric *xi, int irq);
>      void (*ics_resend)(XICSFabric *xi);
>      ICPState *(*icp_get)(XICSFabric *xi, int server);
> +    /* IRQ allocator helpers */
> +    bool (*irq_test)(XICSFabric *xi, int irq);
> +    int (*irq_alloc_block)(XICSFabric *xi, int count, int align);
> +    void (*irq_free_block)(XICSFabric *xi, int irq, int num);
>  } XICSFabricClass;
>  
>  #define XICS_IRQS_SPAPR               1024