Re: [PATCH 4/9] ppc/xive2: Introduce a presenter matching routine

[Greg Kurz]

On Wed, 13 May 2020 17:11:04 +0200
Cédric Le Goater <address@hidden> wrote:

> The VP space is larger in XIVE2 (P10), 24 bits instead of 19bits on
> XIVE (P9), and the CAM line can use a 7bits or 8bits thread id.
> 
> For now, we only use 7bits thread ids, same as P9, but because of the
> change of the size of the VP space, the CAM matching routine is
> different between P9 and P10. It is easier to duplicate the whole
> routine than to add extra handlers in xive_presenter_tctx_match() used
> for P9.
> 

It's a bit of a pity to duplicate this routine. What about turning it
into a helper with some extra arguments and come up with dedicated
users for P9 and P10 ?

> We might come with a better solution later on, after we have added
> some more support for the XIVE2 controller.
> 

Of course if you envision substantial changes that would prevent to share
enough logic, you can ignore the previous comment. The duplicated routine
looks fine.

> Signed-off-by: Cédric Le Goater <address@hidden>
> ---
>  include/hw/ppc/xive2.h |  9 +++++
>  hw/intc/xive2.c        | 87 ++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 96 insertions(+)
> 
> diff --git a/include/hw/ppc/xive2.h b/include/hw/ppc/xive2.h
> index cb15487efdb6..4aefca4d96f1 100644
> --- a/include/hw/ppc/xive2.h
> +++ b/include/hw/ppc/xive2.h
> @@ -60,6 +60,15 @@ int xive2_router_write_nvp(Xive2Router *xrtr, uint8_t 
> nvt_blk, uint32_t nvt_idx,
>  
>  void xive2_router_notify(XiveNotifier *xn, uint32_t lisn);
>  
> +/*
> + * XIVE2 Presenter (POWER10)
> + */
> +
> +int xive2_presenter_tctx_match(XivePresenter *xptr, XiveTCTX *tctx,
> +                                uint8_t format,
> +                                uint8_t nvt_blk, uint32_t nvt_idx,
> +                                bool cam_ignore, uint32_t logic_serv);
> +
>  /*
>   * XIVE2 END ESBs  (POWER10)
>   */
> diff --git a/hw/intc/xive2.c b/hw/intc/xive2.c
> index 15ea04cf1822..1ce9d995e990 100644
> --- a/hw/intc/xive2.c
> +++ b/hw/intc/xive2.c
> @@ -20,6 +20,11 @@
>  #include "hw/ppc/xive2.h"
>  #include "hw/ppc/xive2_regs.h"
>  
> +static inline uint32_t xive_tctx_word2(uint8_t *ring)
> +{
> +    return *((uint32_t *) &ring[TM_WORD2]);
> +}
> +
>  static uint8_t priority_to_ipb(uint8_t priority)
>  {
>      return priority > XIVE_PRIORITY_MAX ?
> @@ -212,6 +217,88 @@ static int xive2_router_get_block_id(Xive2Router *xrtr)
>     return xrc->get_block_id(xrtr);
>  }
>  
> +/*
> + * Encode the HW CAM line with 7bit or 8bit thread id. The thread id
> + * width and block id width is configurable at the IC level.
> + *
> + *    chipid << 19 | 0000000 0 0001 threadid (7Bit)
> + *    chipid << 24 | 0000 0000 0000 0001 threadid (8Bit)
> + */

What about introducing:

#define XIVE2_PIR_TO_NVP_IDX(pir, width) \
    (1 << (width) | ((pir) & ((1 << (width)) - 1))

or any better name you can think of and...

> +static uint32_t xive2_tctx_hw_cam_line(XivePresenter *xptr, XiveTCTX *tctx)
> +{
> +    Xive2Router *xrtr = XIVE2_ROUTER(xptr);
> +    CPUPPCState *env = &POWERPC_CPU(tctx->cs)->env;
> +    uint32_t pir = env->spr_cb[SPR_PIR].default_value;
> +    uint8_t blk = xive2_router_get_block_id(xrtr);
> +    uint8_t tid_shift = 7;
> +    uint8_t tid_mask = (1 << tid_shift) - 1;
> +
> +    return xive2_nvp_cam_line(blk, 1 << tid_shift | (pir & tid_mask));

... turn this into:

    /* We only use 7bit thread ids for now */
    return xive2_nvp_cam_line(blk, XIVE2_PIR_TO_NVP_IDX(pir, 7));

> +}
> +
> +/*
> + * The thread context register words are in big-endian format.
> + */
> +int xive2_presenter_tctx_match(XivePresenter *xptr, XiveTCTX *tctx,
> +                                uint8_t format,
> +                                uint8_t nvt_blk, uint32_t nvt_idx,
> +                                bool cam_ignore, uint32_t logic_serv)
> +{
> +    uint32_t cam =   xive2_nvp_cam_line(nvt_blk, nvt_idx);
> +    uint32_t qw3w2 = xive_tctx_word2(&tctx->regs[TM_QW3_HV_PHYS]);
> +    uint32_t qw2w2 = xive_tctx_word2(&tctx->regs[TM_QW2_HV_POOL]);
> +    uint32_t qw1w2 = xive_tctx_word2(&tctx->regs[TM_QW1_OS]);
> +    uint32_t qw0w2 = xive_tctx_word2(&tctx->regs[TM_QW0_USER]);
> +
> +    /*
> +     * TODO (PowerNV): ignore mode. The low order bits of the NVT
> +     * identifier are ignored in the "CAM" match.
> +     */
> +
> +    if (format == 0) {
> +        if (cam_ignore == true) {
> +            /*
> +             * F=0 & i=1: Logical server notification (bits ignored at
> +             * the end of the NVT identifier)
> +             */
> +            qemu_log_mask(LOG_UNIMP, "XIVE: no support for LS NVT %x/%x\n",
> +                          nvt_blk, nvt_idx);
> +             return -1;
> +        }
> +
> +        /* F=0 & i=0: Specific NVT notification */
> +
> +        /* PHYS ring */
> +        if ((be32_to_cpu(qw3w2) & TM2_QW3W2_VT) &&
> +            cam == xive2_tctx_hw_cam_line(xptr, tctx)) {
> +            return TM_QW3_HV_PHYS;
> +        }
> +
> +        /* HV POOL ring */
> +        if ((be32_to_cpu(qw2w2) & TM2_QW2W2_VP) &&
> +            cam == xive_get_field32(TM2_QW2W2_POOL_CAM, qw2w2)) {
> +            return TM_QW2_HV_POOL;
> +        }
> +
> +        /* OS ring */
> +        if ((be32_to_cpu(qw1w2) & TM2_QW1W2_VO) &&
> +            cam == xive_get_field32(TM2_QW1W2_OS_CAM, qw1w2)) {
> +            return TM_QW1_OS;
> +        }
> +    } else {
> +        /* F=1 : User level Event-Based Branch (EBB) notification */
> +
> +        /* USER ring */
> +        if  ((be32_to_cpu(qw1w2) & TM2_QW1W2_VO) &&
> +             (cam == xive_get_field32(TM2_QW1W2_OS_CAM, qw1w2)) &&
> +             (be32_to_cpu(qw0w2) & TM2_QW0W2_VU) &&
> +             (logic_serv == xive_get_field32(TM2_QW0W2_LOGIC_SERV, qw0w2))) {
> +            return TM_QW0_USER;
> +        }
> +    }
> +    return -1;
> +}
> +
>  static void xive2_router_realize(DeviceState *dev, Error **errp)
>  {
>      Xive2Router *xrtr = XIVE2_ROUTER(dev);