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

["Cédric Le Goater" <clg@kaod.org>]

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

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

> 
>>  sPAPRIrq spapr_irq_xics = {
>> -    .nr_irqs     = XICS_IRQS_SPAPR,
>> +    .nr_irqs     = SPAPR_IRQ_XICS_NR_IRQS,
>> +    .nr_msis     = SPAPR_IRQ_XICS_NR_MSIS,
>>  
>>      .init        = spapr_irq_init_xics,
>>      .claim       = spapr_irq_claim_xics,
>