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

[David Gibson]

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?

> +
>      /* 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;

-- 
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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