Re: [Qemu-devel] [PATCH 2/3] spapr: increase the size of the IRQ number space

[David Gibson <david@gibson.dropbear.id.au>]

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On Mon, Sep 10, 2018 at 01:02:21PM +0200, Cédric Le Goater wrote:
> The new layout using static IRQ number does not leave much space to
> the dynamic MSI range, only 0x100 IRQ numbers. Increase the total
> number of IRQS for newer machines and introduce a legacy XICS backend
> for pre-3.1 machines to maintain compatibility.
> 
> For the old backend, provide a 'nr_msis' value covering the full IRQ
> number space as it does not use the bitmap allocator to allocate MSI
> interrupt numbers.
> 
> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> ---
>  include/hw/ppc/spapr_irq.h |  1 +
>  hw/ppc/spapr.c             |  1 +
>  hw/ppc/spapr_irq.c         | 15 ++++++++++++++-
>  3 files changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/include/hw/ppc/spapr_irq.h b/include/hw/ppc/spapr_irq.h
> index 650f810ad2aa..a467ce696ee4 100644
> --- a/include/hw/ppc/spapr_irq.h
> +++ b/include/hw/ppc/spapr_irq.h
> @@ -41,6 +41,7 @@ typedef struct sPAPRIrq {
>  } sPAPRIrq;
>  
>  extern sPAPRIrq spapr_irq_xics;
> +extern sPAPRIrq spapr_irq_xics_legacy;
>  
>  int spapr_irq_claim(sPAPRMachineState *spapr, int irq, bool lsi, Error **errp);
>  void spapr_irq_free(sPAPRMachineState *spapr, int irq, int num);
> diff --git a/hw/ppc/spapr.c b/hw/ppc/spapr.c
> index 4a9dd4d9bc14..eba7d60a30a7 100644
> --- a/hw/ppc/spapr.c
> +++ b/hw/ppc/spapr.c
> @@ -3971,6 +3971,7 @@ static void spapr_machine_3_0_class_options(MachineClass *mc)
>      SET_MACHINE_COMPAT(mc, SPAPR_COMPAT_3_0);
>  
>      smc->legacy_irq_allocation = true;
> +    smc->irq = &spapr_irq_xics_legacy;
>  }
>  
>  DEFINE_SPAPR_MACHINE(3_0, "3.0", false);
> diff --git a/hw/ppc/spapr_irq.c b/hw/ppc/spapr_irq.c
> index d369ac96f5cd..b14d7bce00ea 100644
> --- a/hw/ppc/spapr_irq.c
> +++ b/hw/ppc/spapr_irq.c
> @@ -195,7 +195,7 @@ static void spapr_irq_print_info_xics(sPAPRMachineState *spapr, Monitor *mon)
>      ics_pic_print_info(spapr->ics, mon);
>  }
>  
> -#define SPAPR_IRQ_XICS_NR_IRQS     XICS_IRQS_SPAPR
> +#define SPAPR_IRQ_XICS_NR_IRQS     0x1000
>  #define SPAPR_IRQ_XICS_NR_MSIS     \
>      (XICS_IRQ_BASE + SPAPR_IRQ_XICS_NR_IRQS - SPAPR_IRQ_MSI)
>  
> @@ -289,3 +289,16 @@ int spapr_irq_find(sPAPRMachineState *spapr, int num, bool align, Error **errp)
>  
>      return first + ics->offset;
>  }
> +
> +#define SPAPR_IRQ_XICS_LEGACY_NR_IRQS     XICS_IRQS_SPAPR

AFAICT this is the last user of XICS_IRQS_SPAPR, so better to put the
constant right here, rather than copying it from a define with a
misleading name.

> +
> +sPAPRIrq spapr_irq_xics_legacy = {
> +    .nr_irqs     = SPAPR_IRQ_XICS_LEGACY_NR_IRQS,
> +    .nr_msis     = SPAPR_IRQ_XICS_LEGACY_NR_IRQS,
> +
> +    .init        = spapr_irq_init_xics,
> +    .claim       = spapr_irq_claim_xics,
> +    .free        = spapr_irq_free_xics,
> +    .qirq        = spapr_qirq_xics,
> +    .print_info  = spapr_irq_print_info_xics,
> +};

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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