Re: [Qemu-devel] [PATCH v5 04/36] ppc/xive: introduce the XiveRouter model

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

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On Fri, Nov 16, 2018 at 11:56:57AM +0100, Cédric Le Goater wrote:
> The XiveRouter models the second sub-engine of the overall XIVE
> architecture : the Interrupt Virtualization Routing Engine (IVRE).
> 
> The IVRE handles event notifications of the IVSE through MMIO stores
> and performs the interrupt routing process. For this purpose, it uses
> a set of table stored in system memory, the first of which being the
> Event Assignment Structure (EAS) table.
> 
> The EAT associates an interrupt source number with an Event Notification
> Descriptor (END) which will be used in a second phase of the routing
> process to identify a Notification Virtual Target.
> 
> The XiveRouter is an abstract class which needs to be inherited from
> to define a storage for the EAT, and other upcoming tables. The
> 'chip-id' atttribute is not strictly necessary for the sPAPR and
> PowerNV machines but it's a good way to test the routing algorithm.
> Without this atttribute, the XiveRouter could be a simple QOM
> interface.
> 
> Signed-off-by: Cédric Le Goater <clg@kaod.org>
> ---
>  include/hw/ppc/xive.h      | 32 ++++++++++++++
>  include/hw/ppc/xive_regs.h | 31 ++++++++++++++
>  hw/intc/xive.c             | 86 ++++++++++++++++++++++++++++++++++++++
>  3 files changed, 149 insertions(+)
>  create mode 100644 include/hw/ppc/xive_regs.h
> 
> diff --git a/include/hw/ppc/xive.h b/include/hw/ppc/xive.h
> index be93fae6317b..5a0696366577 100644
> --- a/include/hw/ppc/xive.h
> +++ b/include/hw/ppc/xive.h
> @@ -11,6 +11,7 @@
>  #define PPC_XIVE_H
>  
>  #include "hw/sysbus.h"

Again, I don't think making this a SysBusDevice is quite right.
Even more so for the router than the source, because at least for PAPR
it might not have any MMIO presence at all.

> +#include "hw/ppc/xive_regs.h"
>  
>  /*
>   * XIVE Fabric (Interface between Source and Router)
> @@ -168,4 +169,35 @@ static inline void xive_source_irq_set(XiveSource *xsrc, uint32_t srcno,
>      }
>  }
>  
> +/*
> + * XIVE Router
> + */
> +
> +typedef struct XiveRouter {
> +    SysBusDevice    parent;
> +
> +    uint32_t        chip_id;

I don't think this belongs in the base class.  The PowerNV specific
variants will need it, but it doesn't make sense for the PAPR version.

> +} XiveRouter;
> +
> +#define TYPE_XIVE_ROUTER "xive-router"
> +#define XIVE_ROUTER(obj)                                \
> +    OBJECT_CHECK(XiveRouter, (obj), TYPE_XIVE_ROUTER)
> +#define XIVE_ROUTER_CLASS(klass)                                        \
> +    OBJECT_CLASS_CHECK(XiveRouterClass, (klass), TYPE_XIVE_ROUTER)
> +#define XIVE_ROUTER_GET_CLASS(obj)                              \
> +    OBJECT_GET_CLASS(XiveRouterClass, (obj), TYPE_XIVE_ROUTER)
> +
> +typedef struct XiveRouterClass {
> +    SysBusDeviceClass parent;
> +
> +    /* XIVE table accessors */
> +    int (*get_eas)(XiveRouter *xrtr, uint32_t lisn, XiveEAS *eas);
> +    int (*set_eas)(XiveRouter *xrtr, uint32_t lisn, XiveEAS *eas);
> +} XiveRouterClass;
> +
> +void xive_eas_pic_print_info(XiveEAS *eas, uint32_t lisn, Monitor *mon);
> +
> +int xive_router_get_eas(XiveRouter *xrtr, uint32_t lisn, XiveEAS *eas);
> +int xive_router_set_eas(XiveRouter *xrtr, uint32_t lisn, XiveEAS *eas);
> +
>  #endif /* PPC_XIVE_H */
> diff --git a/include/hw/ppc/xive_regs.h b/include/hw/ppc/xive_regs.h
> new file mode 100644
> index 000000000000..12499b33614c
> --- /dev/null
> +++ b/include/hw/ppc/xive_regs.h
> @@ -0,0 +1,31 @@
> +/*
> + * QEMU PowerPC XIVE interrupt controller model
> + *
> + * Copyright (c) 2016-2018, IBM Corporation.
> + *
> + * This code is licensed under the GPL version 2 or later. See the
> + * COPYING file in the top-level directory.
> + */
> +
> +#ifndef PPC_XIVE_REGS_H
> +#define PPC_XIVE_REGS_H
> +
> +/* EAS (Event Assignment Structure)
> + *
> + * One per interrupt source. Targets an interrupt to a given Event
> + * Notification Descriptor (END) and provides the corresponding
> + * logical interrupt number (END data)
> + */
> +typedef struct XiveEAS {
> +        /* Use a single 64-bit definition to make it easier to
> +         * perform atomic updates
> +         */
> +        uint64_t        w;
> +#define EAS_VALID       PPC_BIT(0)
> +#define EAS_END_BLOCK   PPC_BITMASK(4, 7)        /* Destination END block# */
> +#define EAS_END_INDEX   PPC_BITMASK(8, 31)       /* Destination END index */
> +#define EAS_MASKED      PPC_BIT(32)              /* Masked */
> +#define EAS_END_DATA    PPC_BITMASK(33, 63)      /* Data written to the END */
> +} XiveEAS;
> +
> +#endif /* PPC_XIVE_REGS_H */
> diff --git a/hw/intc/xive.c b/hw/intc/xive.c
> index 014a2e41f71f..c4c90a25758e 100644
> --- a/hw/intc/xive.c
> +++ b/hw/intc/xive.c
> @@ -442,6 +442,91 @@ static const TypeInfo xive_source_info = {
>      .class_init    = xive_source_class_init,
>  };
>  
> +/*
> + * XIVE Router (aka. Virtualization Controller or IVRE)
> + */
> +
> +int xive_router_get_eas(XiveRouter *xrtr, uint32_t lisn, XiveEAS *eas)
> +{
> +    XiveRouterClass *xrc = XIVE_ROUTER_GET_CLASS(xrtr);
> +
> +    return xrc->get_eas(xrtr, lisn, eas);
> +}
> +
> +int xive_router_set_eas(XiveRouter *xrtr, uint32_t lisn, XiveEAS *eas)
> +{
> +    XiveRouterClass *xrc = XIVE_ROUTER_GET_CLASS(xrtr);
> +
> +    return xrc->set_eas(xrtr, lisn, eas);
> +}
> +
> +static void xive_router_notify(XiveFabric *xf, uint32_t lisn)
> +{
> +    XiveRouter *xrtr = XIVE_ROUTER(xf);
> +    XiveEAS eas;
> +
> +    /* EAS cache lookup */
> +    if (xive_router_get_eas(xrtr, lisn, &eas)) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "XIVE: Unknown LISN %x\n", lisn);
> +        return;
> +    }

AFAICT a bad LISN here means a qemu error (in the source, probably),
not a user or guest error, so an assert() would be more appropriate.

> +
> +    /* The IVRE has a State Bit Cache for its internal sources which
> +     * is also involed at this point. We skip the SBC lookup because
> +     * the state bits of the sources are modeled internally in QEMU.
> +     */
> +
> +    if (!(eas.w & EAS_VALID)) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "XIVE: invalid LISN %x\n", lisn);
> +        return;
> +    }
> +
> +    if (eas.w & EAS_MASKED) {
> +        /* Notification completed */
> +        return;
> +    }
> +}
> +
> +static Property xive_router_properties[] = {
> +    DEFINE_PROP_UINT32("chip-id", XiveRouter, chip_id, 0),
> +    DEFINE_PROP_END_OF_LIST(),
> +};
> +
> +static void xive_router_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +    XiveFabricClass *xfc = XIVE_FABRIC_CLASS(klass);
> +
> +    dc->desc    = "XIVE Router Engine";
> +    dc->props   = xive_router_properties;
> +    xfc->notify = xive_router_notify;
> +}
> +
> +static const TypeInfo xive_router_info = {
> +    .name          = TYPE_XIVE_ROUTER,
> +    .parent        = TYPE_SYS_BUS_DEVICE,
> +    .abstract      = true,
> +    .class_size    = sizeof(XiveRouterClass),
> +    .class_init    = xive_router_class_init,
> +    .interfaces    = (InterfaceInfo[]) {
> +        { TYPE_XIVE_FABRIC },

So as far as I can see so far, the XiveFabric interface will
essentially have to be implemented on the router object, so I'm not
seeing much point to having the interface rather than just a direct
call on the router object.  But I haven't read the whole series yet,
so maybe I'm missing something.


> +        { }
> +    }
> +};
> +
> +void xive_eas_pic_print_info(XiveEAS *eas, uint32_t lisn, Monitor *mon)
> +{
> +    if (!(eas->w & EAS_VALID)) {
> +        return;
> +    }
> +
> +    monitor_printf(mon, "  %08x %s end:%02x/%04x data:%08x\n",
> +                   lisn, eas->w & EAS_MASKED ? "M" : " ",
> +                   (uint8_t)  GETFIELD(EAS_END_BLOCK, eas->w),
> +                   (uint32_t) GETFIELD(EAS_END_INDEX, eas->w),
> +                   (uint32_t) GETFIELD(EAS_END_DATA, eas->w));
> +}
> +
>  /*
>   * XIVE Fabric
>   */
> @@ -455,6 +540,7 @@ static void xive_register_types(void)
>  {
>      type_register_static(&xive_source_info);
>      type_register_static(&xive_fabric_info);
> +    type_register_static(&xive_router_info);
>  }
>  
>  type_init(xive_register_types)

-- 
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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