Re: [Qemu-devel] [PATCH 1/3] spapr: introduce a spapr_irq class 'nr_msis' attribute

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

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On Tue, Sep 11, 2018 at 06:41:24AM +0200, Cédric Le Goater wrote:
> On 09/11/2018 03:48 AM, David Gibson wrote:
> > On Mon, Sep 10, 2018 at 01:02:20PM +0200, Cédric Le Goater wrote:
> > 11;rgb:ffff/ffff/ffff> The number of MSI interrupts a sPAPR machine can allocate is in direct
> >> relation with the number of interrupts of the sPAPRIrq backend. Define
> >> statically this value at the sPAPRIrq class level.
> >>
> >> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> >> ---
> >>  include/hw/ppc/spapr_irq.h | 1 +
> >>  hw/ppc/spapr_irq.c         | 9 +++++++--
> >>  2 files changed, 8 insertions(+), 2 deletions(-)
> >>
> >> diff --git a/include/hw/ppc/spapr_irq.h b/include/hw/ppc/spapr_irq.h
> >> index 0e98c4474bb2..650f810ad2aa 100644
> >> --- a/include/hw/ppc/spapr_irq.h
> >> +++ b/include/hw/ppc/spapr_irq.h
> >> @@ -31,6 +31,7 @@ void spapr_irq_msi_reset(sPAPRMachineState *spapr);
> >>  
> >>  typedef struct sPAPRIrq {
> >>      uint32_t    nr_irqs;
> >> +    uint32_t    nr_msis;
> >>  
> >>      void (*init)(sPAPRMachineState *spapr, Error **errp);
> >>      int (*claim)(sPAPRMachineState *spapr, int irq, bool lsi, Error **errp);
> >> diff --git a/hw/ppc/spapr_irq.c b/hw/ppc/spapr_irq.c
> >> index 0cbb5dd39368..d369ac96f5cd 100644
> >> --- a/hw/ppc/spapr_irq.c
> >> +++ b/hw/ppc/spapr_irq.c
> >> @@ -99,7 +99,7 @@ static void spapr_irq_init_xics(sPAPRMachineState *spapr, Error **errp)
> >>  
> >>      /* Initialize the MSI IRQ allocator. */
> >>      if (!SPAPR_MACHINE_GET_CLASS(spapr)->legacy_irq_allocation) {
> >> -        spapr_irq_msi_init(spapr, XICS_IRQ_BASE + nr_irqs - SPAPR_IRQ_MSI);
> >> +        spapr_irq_msi_init(spapr, smc->irq->nr_msis);
> >>      }
> >>  
> >>      if (kvm_enabled()) {
> >> @@ -195,8 +195,13 @@ 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_MSIS     \
> >> +    (XICS_IRQ_BASE + SPAPR_IRQ_XICS_NR_IRQS - SPAPR_IRQ_MSI)
> > 
> > Uh.. I'm not quite understanding how XICS_IRQ_BASE gets into this.
> 
> because the IRQ ranges of the new static IRQ number space start at 
> the sPAPR IRQ number offset.
> 
> XICS_IRQ_BASE		0x1000
> SPAPR_IRQ_XICS_NR_IRQS	0x400
> 
> SPAPR_IRQ_MSI		0x1300
> 
> 0x1000 + 0x400 - 0x1300 = 0x100

Duh, sorry, that's kind of obvious.  Apparently my brain wasn't
working the other day.

> we could use SPAPR_IRQ_EPOW instead or some other value defining 
> the IRQ0 number.

No, it's fine.

-- 
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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