Re: [Qemu-devel] [PATCH v5 05/36] ppc/xive: introduce the XIVE Event Notification Descriptors

[David Gibson]

On Fri, Nov 16, 2018 at 11:56:58AM +0100, Cédric Le Goater wrote:
> To complete the event routing, the IVRE sub-engine uses an internal
> table containing Event Notification Descriptor (END) structures.
> 
> An END specifies on which Event Queue (EQ) the event notification
> data, defined in the associated EAS, should be posted when an
> exception occurs. It also defines which Notification Virtual Target
> (NVT) should be notified.
> 
> The Event Queue is a memory page provided by the O/S defining a
> circular buffer, one per server and priority couple, containing Event
> Queue entries. These are 4 bytes long, the first bit being a
> 'generation' bit and the 31 following bits the END Data field. They
> are pulled by the O/S when the exception occurs.
> 
> The END Data field is a way to set an invariant logical event source
> number for an IRQ. It is set with the H_INT_SET_SOURCE_CONFIG hcall
> when the EISN flag is used.
> 
> Signed-off-by: Cédric Le Goater <address@hidden>
> ---
>  include/hw/ppc/xive.h      |  18 ++++
>  include/hw/ppc/xive_regs.h |  48 ++++++++++
>  hw/intc/xive.c             | 185 ++++++++++++++++++++++++++++++++++++-
>  3 files changed, 248 insertions(+), 3 deletions(-)
> 
> diff --git a/include/hw/ppc/xive.h b/include/hw/ppc/xive.h
> index 5a0696366577..ce62aaf28343 100644
> --- a/include/hw/ppc/xive.h
> +++ b/include/hw/ppc/xive.h
> @@ -193,11 +193,29 @@ typedef struct XiveRouterClass {
>      /* XIVE table accessors */
>      int (*get_eas)(XiveRouter *xrtr, uint32_t lisn, XiveEAS *eas);
>      int (*set_eas)(XiveRouter *xrtr, uint32_t lisn, XiveEAS *eas);
> +    int (*get_end)(XiveRouter *xrtr, uint8_t end_blk, uint32_t end_idx,
> +                   XiveEND *end);
> +    int (*set_end)(XiveRouter *xrtr, uint8_t end_blk, uint32_t end_idx,
> +                   XiveEND *end);

Hrm.  So unlike the EAS, which is basically just a word, the END is a
pretty large structure.  It's unclear here if get/set are expected to
copy the whole thing out and in, or if get get give you a pointer into
a "live" structure and set just does any necessary barriers after an
update.

Really, for a non-atomic value like this, I'm not sure get/set is the
right model.

Also as I understand it nearly all the indices in XIVE are broken into
block/index.  Is there a reason those are folded together into lisn
for the EAS, but not for the END?

>  } 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);
> +int xive_router_get_end(XiveRouter *xrtr, uint8_t end_blk, uint32_t end_idx,
> +                        XiveEND *end);
> +int xive_router_set_end(XiveRouter *xrtr, uint8_t end_blk, uint32_t end_idx,
> +                        XiveEND *end);
> +
> +/*
> + * For legacy compatibility, the exceptions define up to 256 different
> + * priorities. P9 implements only 9 levels : 8 active levels [0 - 7]
> + * and the least favored level 0xFF.
> + */
> +#define XIVE_PRIORITY_MAX  7
> +
> +void xive_end_reset(XiveEND *end);
> +void xive_end_pic_print_info(XiveEND *end, uint32_t end_idx, Monitor *mon);
>  
>  #endif /* PPC_XIVE_H */
> diff --git a/include/hw/ppc/xive_regs.h b/include/hw/ppc/xive_regs.h
> index 12499b33614c..f97fb2b90bee 100644
> --- a/include/hw/ppc/xive_regs.h
> +++ b/include/hw/ppc/xive_regs.h
> @@ -28,4 +28,52 @@ typedef struct XiveEAS {
>  #define EAS_END_DATA    PPC_BITMASK(33, 63)      /* Data written to the END 
> */
>  } XiveEAS;
>  
> +/* Event Notification Descriptor (END) */
> +typedef struct XiveEND {
> +        uint32_t        w0;
> +#define END_W0_VALID             PPC_BIT32(0) /* "v" bit */
> +#define END_W0_ENQUEUE           PPC_BIT32(1) /* "q" bit */
> +#define END_W0_UCOND_NOTIFY      PPC_BIT32(2) /* "n" bit */
> +#define END_W0_BACKLOG           PPC_BIT32(3) /* "b" bit */
> +#define END_W0_PRECL_ESC_CTL     PPC_BIT32(4) /* "p" bit */
> +#define END_W0_ESCALATE_CTL      PPC_BIT32(5) /* "e" bit */
> +#define END_W0_UNCOND_ESCALATE   PPC_BIT32(6) /* "u" bit - DD2.0 */
> +#define END_W0_SILENT_ESCALATE   PPC_BIT32(7) /* "s" bit - DD2.0 */
> +#define END_W0_QSIZE             PPC_BITMASK32(12, 15)
> +#define END_W0_SW0               PPC_BIT32(16)
> +#define END_W0_FIRMWARE          END_W0_SW0 /* Owned by FW */
> +#define END_QSIZE_4K             0
> +#define END_QSIZE_64K            4
> +#define END_W0_HWDEP             PPC_BITMASK32(24, 31)
> +        uint32_t        w1;
> +#define END_W1_ESn               PPC_BITMASK32(0, 1)
> +#define END_W1_ESn_P             PPC_BIT32(0)
> +#define END_W1_ESn_Q             PPC_BIT32(1)
> +#define END_W1_ESe               PPC_BITMASK32(2, 3)
> +#define END_W1_ESe_P             PPC_BIT32(2)
> +#define END_W1_ESe_Q             PPC_BIT32(3)
> +#define END_W1_GENERATION        PPC_BIT32(9)
> +#define END_W1_PAGE_OFF          PPC_BITMASK32(10, 31)
> +        uint32_t        w2;
> +#define END_W2_MIGRATION_REG     PPC_BITMASK32(0, 3)
> +#define END_W2_OP_DESC_HI        PPC_BITMASK32(4, 31)
> +        uint32_t        w3;
> +#define END_W3_OP_DESC_LO        PPC_BITMASK32(0, 31)
> +        uint32_t        w4;
> +#define END_W4_ESC_END_BLOCK     PPC_BITMASK32(4, 7)
> +#define END_W4_ESC_END_INDEX     PPC_BITMASK32(8, 31)
> +        uint32_t        w5;
> +#define END_W5_ESC_END_DATA      PPC_BITMASK32(1, 31)
> +        uint32_t        w6;
> +#define END_W6_FORMAT_BIT        PPC_BIT32(8)
> +#define END_W6_NVT_BLOCK         PPC_BITMASK32(9, 12)
> +#define END_W6_NVT_INDEX         PPC_BITMASK32(13, 31)
> +        uint32_t        w7;
> +#define END_W7_F0_IGNORE         PPC_BIT32(0)
> +#define END_W7_F0_BLK_GROUPING   PPC_BIT32(1)
> +#define END_W7_F0_PRIORITY       PPC_BITMASK32(8, 15)
> +#define END_W7_F1_WAKEZ          PPC_BIT32(0)
> +#define END_W7_F1_LOG_SERVER_ID  PPC_BITMASK32(1, 31)
> +} XiveEND;
> +
>  #endif /* PPC_XIVE_REGS_H */
> diff --git a/hw/intc/xive.c b/hw/intc/xive.c
> index c4c90a25758e..9cb001e7b540 100644
> --- a/hw/intc/xive.c
> +++ b/hw/intc/xive.c
> @@ -442,6 +442,101 @@ static const TypeInfo xive_source_info = {
>      .class_init    = xive_source_class_init,
>  };
>  
> +/*
> + * XiveEND helpers
> + */
> +
> +void xive_end_reset(XiveEND *end)
> +{
> +    memset(end, 0, sizeof(*end));
> +
> +    /* switch off the escalation and notification ESBs */
> +    end->w1 = END_W1_ESe_Q | END_W1_ESn_Q;

It's not obvious to me what circumstances this would be called under.
Since the ENDs are in system memory, a memset() seems like an odd
thing for (virtual) hardware to be doing to it.

> +}
> +
> +static void xive_end_queue_pic_print_info(XiveEND *end, uint32_t width,
> +                                          Monitor *mon)
> +{
> +    uint64_t qaddr_base = (((uint64_t)(end->w2 & 0x0fffffff)) << 32) | 
> end->w3;
> +    uint32_t qsize = GETFIELD(END_W0_QSIZE, end->w0);
> +    uint32_t qindex = GETFIELD(END_W1_PAGE_OFF, end->w1);
> +    uint32_t qentries = 1 << (qsize + 10);
> +    int i;
> +
> +    /*
> +     * print out the [ (qindex - (width - 1)) .. (qindex + 1)] window
> +     */
> +    monitor_printf(mon, " [ ");
> +    qindex = (qindex - (width - 1)) & (qentries - 1);
> +    for (i = 0; i < width; i++) {
> +        uint64_t qaddr = qaddr_base + (qindex << 2);
> +        uint32_t qdata = -1;
> +
> +        if (dma_memory_read(&address_space_memory, qaddr, &qdata,
> +                            sizeof(qdata))) {
> +            qemu_log_mask(LOG_GUEST_ERROR, "XIVE: failed to read EQ @0x%"
> +                          HWADDR_PRIx "\n", qaddr);
> +            return;
> +        }
> +        monitor_printf(mon, "%s%08x ", i == width - 1 ? "^" : "",
> +                       be32_to_cpu(qdata));
> +        qindex = (qindex + 1) & (qentries - 1);
> +    }
> +    monitor_printf(mon, "]\n");
> +}
> +
> +void xive_end_pic_print_info(XiveEND *end, uint32_t end_idx, Monitor *mon)
> +{
> +    uint64_t qaddr_base = (((uint64_t)(end->w2 & 0x0fffffff)) << 32) | 
> end->w3;
> +    uint32_t qindex = GETFIELD(END_W1_PAGE_OFF, end->w1);
> +    uint32_t qgen = GETFIELD(END_W1_GENERATION, end->w1);
> +    uint32_t qsize = GETFIELD(END_W0_QSIZE, end->w0);
> +    uint32_t qentries = 1 << (qsize + 10);
> +
> +    uint32_t nvt = GETFIELD(END_W6_NVT_INDEX, end->w6);
> +    uint8_t priority = GETFIELD(END_W7_F0_PRIORITY, end->w7);
> +
> +    if (!(end->w0 & END_W0_VALID)) {
> +        return;
> +    }
> +
> +    monitor_printf(mon, "  %08x %c%c%c%c%c prio:%d nvt:%04x eq:@%08"PRIx64
> +                   "% 6d/%5d ^%d", end_idx,
> +                   end->w0 & END_W0_VALID ? 'v' : '-',
> +                   end->w0 & END_W0_ENQUEUE ? 'q' : '-',
> +                   end->w0 & END_W0_UCOND_NOTIFY ? 'n' : '-',
> +                   end->w0 & END_W0_BACKLOG ? 'b' : '-',
> +                   end->w0 & END_W0_ESCALATE_CTL ? 'e' : '-',
> +                   priority, nvt, qaddr_base, qindex, qentries, qgen);
> +
> +    xive_end_queue_pic_print_info(end, 6, mon);
> +}
> +
> +static void xive_end_push(XiveEND *end, uint32_t data)

s/push/enqueue/ please, "push" suggests a stack.  (Not to mention that
"push" and "pull" are used as terms elsewhere in XIVE).

> +{
> +    uint64_t qaddr_base = (((uint64_t)(end->w2 & 0x0fffffff)) << 32) | 
> end->w3;
> +    uint32_t qsize = GETFIELD(END_W0_QSIZE, end->w0);
> +    uint32_t qindex = GETFIELD(END_W1_PAGE_OFF, end->w1);
> +    uint32_t qgen = GETFIELD(END_W1_GENERATION, end->w1);
> +
> +    uint64_t qaddr = qaddr_base + (qindex << 2);
> +    uint32_t qdata = cpu_to_be32((qgen << 31) | (data & 0x7fffffff));
> +    uint32_t qentries = 1 << (qsize + 10);
> +
> +    if (dma_memory_write(&address_space_memory, qaddr, &qdata, 
> sizeof(qdata))) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "XIVE: failed to write END data @0x%"
> +                      HWADDR_PRIx "\n", qaddr);
> +        return;
> +    }
> +
> +    qindex = (qindex + 1) & (qentries - 1);
> +    if (qindex == 0) {
> +        qgen ^= 1;
> +        end->w1 = SETFIELD(END_W1_GENERATION, end->w1, qgen);
> +    }
> +    end->w1 = SETFIELD(END_W1_PAGE_OFF, end->w1, qindex);
> +}
> +
>  /*
>   * XIVE Router (aka. Virtualization Controller or IVRE)
>   */
> @@ -460,6 +555,82 @@ int xive_router_set_eas(XiveRouter *xrtr, uint32_t lisn, 
> XiveEAS *eas)
>      return xrc->set_eas(xrtr, lisn, eas);
>  }
>  
> +int xive_router_get_end(XiveRouter *xrtr, uint8_t end_blk, uint32_t end_idx,
> +                        XiveEND *end)
> +{
> +   XiveRouterClass *xrc = XIVE_ROUTER_GET_CLASS(xrtr);
> +
> +   return xrc->get_end(xrtr, end_blk, end_idx, end);
> +}
> +
> +int xive_router_set_end(XiveRouter *xrtr, uint8_t end_blk, uint32_t end_idx,
> +                        XiveEND *end)
> +{
> +   XiveRouterClass *xrc = XIVE_ROUTER_GET_CLASS(xrtr);
> +
> +   return xrc->set_end(xrtr, end_blk, end_idx, end);
> +}
> +
> +/*
> + * An END trigger can come from an event trigger (IPI or HW) or from
> + * another chip. We don't model the PowerBus but the END trigger
> + * message has the same parameters than in the function below.
> + */
> +static void xive_router_end_notify(XiveRouter *xrtr, uint8_t end_blk,
> +                                   uint32_t end_idx, uint32_t end_data)
> +{
> +    XiveEND end;
> +    uint8_t priority;
> +    uint8_t format;
> +
> +    /* END cache lookup */
> +    if (xive_router_get_end(xrtr, end_blk, end_idx, &end)) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "XIVE: No END %x/%x\n", end_blk,
> +                      end_idx);
> +        return;
> +    }
> +
> +    if (!(end.w0 & END_W0_VALID)) {
> +        qemu_log_mask(LOG_GUEST_ERROR, "XIVE: END %x/%x is invalid\n",
> +                      end_blk, end_idx);
> +        return;
> +    }
> +
> +    if (end.w0 & END_W0_ENQUEUE) {
> +        xive_end_push(&end, end_data);
> +        xive_router_set_end(xrtr, end_blk, end_idx, &end);
> +    }
> +
> +    /*
> +     * The W7 format depends on the F bit in W6. It defines the type
> +     * of the notification :
> +     *
> +     *   F=0 : single or multiple NVT notification
> +     *   F=1 : User level Event-Based Branch (EBB) notification, no
> +     *         priority
> +     */
> +    format = GETFIELD(END_W6_FORMAT_BIT, end.w6);
> +    priority = GETFIELD(END_W7_F0_PRIORITY, end.w7);
> +
> +    /* The END is masked */
> +    if (format == 0 && priority == 0xff) {
> +        return;
> +    }
> +
> +    /*
> +     * Check the END ESn (Event State Buffer for notification) for
> +     * even futher coalescing in the Router
> +     */
> +    if (!(end.w0 & END_W0_UCOND_NOTIFY)) {
> +        qemu_log_mask(LOG_UNIMP, "XIVE: !UCOND_NOTIFY not implemented\n");
> +        return;
> +    }
> +
> +    /*
> +     * Follows IVPE notification
> +     */
> +}
> +
>  static void xive_router_notify(XiveFabric *xf, uint32_t lisn)
>  {
>      XiveRouter *xrtr = XIVE_ROUTER(xf);
> @@ -471,9 +642,9 @@ static void xive_router_notify(XiveFabric *xf, uint32_t 
> lisn)
>          return;
>      }
>  
> -    /* 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.
> +    /* The IVRE checks the State Bit Cache at this point. We skip the
> +     * SBC lookup because the state bits of the sources are modeled
> +     * internally in QEMU.

Replacing a comment about something we're not doing with a different
comment about something we're not doing doesn't seem very useful.
Maybe fold these together into one patch or the other.

>       */
>  
>      if (!(eas.w & EAS_VALID)) {
> @@ -485,6 +656,14 @@ static void xive_router_notify(XiveFabric *xf, uint32_t 
> lisn)
>          /* Notification completed */
>          return;
>      }
> +
> +    /*
> +     * The event trigger becomes an END trigger
> +     */
> +    xive_router_end_notify(xrtr,
> +                           GETFIELD(EAS_END_BLOCK, eas.w),
> +                           GETFIELD(EAS_END_INDEX, eas.w),
> +                           GETFIELD(EAS_END_DATA,  eas.w));
>  }
>  
>  static Property xive_router_properties[] = {

-- 
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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