Re: [Qemu-devel] [PATCH 11/25] spapr: describe the XIVE interrupt source flags

[Cédric Le Goater]

On 11/28/2017 06:40 AM, David Gibson wrote:
> On Thu, Nov 23, 2017 at 02:29:41PM +0100, Cédric Le Goater wrote:
>> The XIVE interrupt sources can have different characteristics depending
>> on their nature and the HW level in use. The sPAPR specs provide a set of
>> flags to describe them :
>>
>>  - XIVE_SRC_H_INT_ESB  the Event State Buffers are controlled with a
>>                        specific hcall H_INT_ESB and not with MMIO
>>  - XIVE_SRC_LSI        LSI or MSI source (ICSIRQState level)
>>  - XIVE_SRC_TRIGGER    the full function page supports trigger
>>  - XIVE_SRC_STORE_EOI  EOI can be done with a store.
>>
>> Our QEMU emulation of XIVE for the sPAPR machine gathers all sources under
>> a same model and provides a common source with the XIVE_SRC_TRIGGER type.
>> So, the above list is mostly informative apart from the XIVE_SRC_LSI flag
>> which will be deduced from the XIVE_STATUS_LSI flag.
>>
>> The OS retrieves this information on the source with the
>> H_INT_GET_SOURCE_INFO hcall.
>>
>> Signed-off-by: Cédric Le Goater <address@hidden>
>> ---
>>  hw/intc/spapr_xive.c        | 4 ++++
>>  include/hw/ppc/spapr_xive.h | 7 +++++++
>>  2 files changed, 11 insertions(+)
>>
>> diff --git a/hw/intc/spapr_xive.c b/hw/intc/spapr_xive.c
>> index f45f50fd017e..b1e3f8710cff 100644
>> --- a/hw/intc/spapr_xive.c
>> +++ b/hw/intc/spapr_xive.c
>> @@ -368,6 +368,10 @@ static void spapr_xive_realize(DeviceState *dev, Error 
>> **errp)
>>      /* Allocate the IVT (Interrupt Virtualization Table) */
>>      xive->ivt = g_malloc0(xive->nr_irqs * sizeof(XiveIVE));
>>  
>> +    /* All sources are emulated under the XIVE object and share the
>> +     * same characteristic */
>> +    xive->flags = XIVE_SRC_TRIGGER;
> 
> You never actually use this field.  And since it always has the same
> value, is there a point to storing it?

yep. not much. This is a left over. 

I will keep the defines and move the value to the XIVE hcall layer where 
it is used.

Thanks,

C.  

>> +
>>      /* Allocate SBEs (State Bit Entry). 2 bits, so 4 entries per byte */
>>      xive->sbe_size = DIV_ROUND_UP(xive->nr_irqs, 4);
>>      xive->sbe = g_malloc0(xive->sbe_size);
>> diff --git a/include/hw/ppc/spapr_xive.h b/include/hw/ppc/spapr_xive.h
>> index 84c910e62e56..7a308fb4db2b 100644
>> --- a/include/hw/ppc/spapr_xive.h
>> +++ b/include/hw/ppc/spapr_xive.h
>> @@ -40,6 +40,13 @@ struct sPAPRXive {
>>  #define XIVE_STATUS_SENT               0x4
>>      uint8_t      *status;
>>  
>> +    /* Interrupt source flags */
>> +#define XIVE_SRC_H_INT_ESB     (1ull << (63 - 60))
>> +#define XIVE_SRC_LSI           (1ull << (63 - 61))
>> +#define XIVE_SRC_TRIGGER       (1ull << (63 - 62))
>> +#define XIVE_SRC_STORE_EOI     (1ull << (63 - 63))
>> +    uint32_t     flags;
>> +
>>      /* XIVE internal tables */
>>      XiveIVE      *ivt;
>>      uint8_t      *sbe;
>