Re: [Qemu-devel] [PATCH 03/10] ppc/pnv: Rework cache watch model of PnvXIVE

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

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On Sun, Jun 30, 2019 at 10:45:54PM +0200, Cédric Le Goater wrote:
> When the software modifies the XIVE internal structures, ESB, EAS,
> END, NVT, it also must update the caches of the different XIVE
> sub-engines. HW offers a set of common interface for such purpose.
> 
> The CWATCH_SPEC register defines the block/index of the target and a
> set of flags to perform a full update and to watch for update
> conflicts.
> 
> The cache watch CWATCH_DATAX registers are then loaded with the target
> data with a first read on CWATCH_DATA0. Writing back is done in the
> opposit order, CWATCH_DATA0 triggering the update.
> 
> The SCRUB_TRIG registers are used to flush the cache in RAM, and to
> possibly invalidate it. Cache disablement is also an option but as we
> do not model the cache, these registers are no-ops
> 
> Today, the modeling of these registers is incorrect but it did not
> impact the set up of a baremetal system. However, running KVM requires
> a rework.
> 
> Fixes: 2dfa91a2aa5a ("ppc/pnv: add a XIVE interrupt controller model for POWER9")
> Signed-off-by: Cédric Le Goater <clg@kaod.org>

Pushing it for what counts as a bugfix this close to freeze, but I'll
take it.  Applied to ppc-for-4.1.

> ---
>  hw/intc/pnv_xive.c | 142 +++++++++++++++++++++++++++++++++------------
>  1 file changed, 106 insertions(+), 36 deletions(-)
> 
> diff --git a/hw/intc/pnv_xive.c b/hw/intc/pnv_xive.c
> index 9ab77feee9d8..4dc92ef1e372 100644
> --- a/hw/intc/pnv_xive.c
> +++ b/hw/intc/pnv_xive.c
> @@ -169,7 +169,7 @@ static uint64_t pnv_xive_vst_addr_indirect(PnvXive *xive, uint32_t type,
>      vsd = ldq_be_dma(&address_space_memory, vsd_addr);
>  
>      if (!(vsd & VSD_ADDRESS_MASK)) {
> -        xive_error(xive, "VST: invalid %s entry %x !?", info->name, 0);
> +        xive_error(xive, "VST: invalid %s entry %x !?", info->name, idx);
>          return 0;
>      }
>  
> @@ -190,7 +190,7 @@ static uint64_t pnv_xive_vst_addr_indirect(PnvXive *xive, uint32_t type,
>          vsd = ldq_be_dma(&address_space_memory, vsd_addr);
>  
>          if (!(vsd & VSD_ADDRESS_MASK)) {
> -            xive_error(xive, "VST: invalid %s entry %x !?", info->name, 0);
> +            xive_error(xive, "VST: invalid %s entry %x !?", info->name, idx);
>              return 0;
>          }
>  
> @@ -294,8 +294,12 @@ static int pnv_xive_write_end(XiveRouter *xrtr, uint8_t blk, uint32_t idx,
>                                word_number);
>  }
>  
> -static int pnv_xive_end_update(PnvXive *xive, uint8_t blk, uint32_t idx)
> +static int pnv_xive_end_update(PnvXive *xive)
>  {
> +    uint8_t  blk = GETFIELD(VC_EQC_CWATCH_BLOCKID,
> +                           xive->regs[(VC_EQC_CWATCH_SPEC >> 3)]);
> +    uint32_t idx = GETFIELD(VC_EQC_CWATCH_OFFSET,
> +                           xive->regs[(VC_EQC_CWATCH_SPEC >> 3)]);
>      int i;
>      uint64_t eqc_watch[4];
>  
> @@ -307,6 +311,24 @@ static int pnv_xive_end_update(PnvXive *xive, uint8_t blk, uint32_t idx)
>                                XIVE_VST_WORD_ALL);
>  }
>  
> +static void pnv_xive_end_cache_load(PnvXive *xive)
> +{
> +    uint8_t  blk = GETFIELD(VC_EQC_CWATCH_BLOCKID,
> +                           xive->regs[(VC_EQC_CWATCH_SPEC >> 3)]);
> +    uint32_t idx = GETFIELD(VC_EQC_CWATCH_OFFSET,
> +                           xive->regs[(VC_EQC_CWATCH_SPEC >> 3)]);
> +    uint64_t eqc_watch[4] = { 0 };
> +    int i;
> +
> +    if (pnv_xive_vst_read(xive, VST_TSEL_EQDT, blk, idx, eqc_watch)) {
> +        xive_error(xive, "VST: no END entry %x/%x !?", blk, idx);
> +    }
> +
> +    for (i = 0; i < ARRAY_SIZE(eqc_watch); i++) {
> +        xive->regs[(VC_EQC_CWATCH_DAT0 >> 3) + i] = be64_to_cpu(eqc_watch[i]);
> +    }
> +}
> +
>  static int pnv_xive_get_nvt(XiveRouter *xrtr, uint8_t blk, uint32_t idx,
>                              XiveNVT *nvt)
>  {
> @@ -320,8 +342,12 @@ static int pnv_xive_write_nvt(XiveRouter *xrtr, uint8_t blk, uint32_t idx,
>                                word_number);
>  }
>  
> -static int pnv_xive_nvt_update(PnvXive *xive, uint8_t blk, uint32_t idx)
> +static int pnv_xive_nvt_update(PnvXive *xive)
>  {
> +    uint8_t  blk = GETFIELD(PC_VPC_CWATCH_BLOCKID,
> +                           xive->regs[(PC_VPC_CWATCH_SPEC >> 3)]);
> +    uint32_t idx = GETFIELD(PC_VPC_CWATCH_OFFSET,
> +                           xive->regs[(PC_VPC_CWATCH_SPEC >> 3)]);
>      int i;
>      uint64_t vpc_watch[8];
>  
> @@ -333,6 +359,24 @@ static int pnv_xive_nvt_update(PnvXive *xive, uint8_t blk, uint32_t idx)
>                                XIVE_VST_WORD_ALL);
>  }
>  
> +static void pnv_xive_nvt_cache_load(PnvXive *xive)
> +{
> +    uint8_t  blk = GETFIELD(PC_VPC_CWATCH_BLOCKID,
> +                           xive->regs[(PC_VPC_CWATCH_SPEC >> 3)]);
> +    uint32_t idx = GETFIELD(PC_VPC_CWATCH_OFFSET,
> +                           xive->regs[(PC_VPC_CWATCH_SPEC >> 3)]);
> +    uint64_t vpc_watch[8] = { 0 };
> +    int i;
> +
> +    if (pnv_xive_vst_read(xive, VST_TSEL_VPDT, blk, idx, vpc_watch)) {
> +        xive_error(xive, "VST: no NVT entry %x/%x !?", blk, idx);
> +    }
> +
> +    for (i = 0; i < ARRAY_SIZE(vpc_watch); i++) {
> +        xive->regs[(PC_VPC_CWATCH_DAT0 >> 3) + i] = be64_to_cpu(vpc_watch[i]);
> +    }
> +}
> +
>  static int pnv_xive_get_eas(XiveRouter *xrtr, uint8_t blk, uint32_t idx,
>                              XiveEAS *eas)
>  {
> @@ -346,12 +390,6 @@ static int pnv_xive_get_eas(XiveRouter *xrtr, uint8_t blk, uint32_t idx,
>      return pnv_xive_vst_read(xive, VST_TSEL_IVT, blk, idx, eas);
>  }
>  
> -static int pnv_xive_eas_update(PnvXive *xive, uint8_t blk, uint32_t idx)
> -{
> -    /* All done. */
> -    return 0;
> -}
> -
>  static XiveTCTX *pnv_xive_get_tctx(XiveRouter *xrtr, CPUState *cs)
>  {
>      PowerPCCPU *cpu = POWERPC_CPU(cs);
> @@ -950,28 +988,43 @@ static void pnv_xive_ic_reg_write(void *opaque, hwaddr offset,
>       * XIVE PC & VC cache updates for EAS, NVT and END
>       */
>      case VC_IVC_SCRUB_MASK:
> -        break;
>      case VC_IVC_SCRUB_TRIG:
> -        pnv_xive_eas_update(xive, GETFIELD(PC_SCRUB_BLOCK_ID, val),
> -                            GETFIELD(VC_SCRUB_OFFSET, val));
>          break;
>  
> -    case VC_EQC_SCRUB_MASK:
>      case VC_EQC_CWATCH_SPEC:
> -    case VC_EQC_CWATCH_DAT0 ... VC_EQC_CWATCH_DAT3:
> +        val &= ~VC_EQC_CWATCH_CONFLICT; /* HW resets this bit */
> +        break;
> +    case VC_EQC_CWATCH_DAT1 ... VC_EQC_CWATCH_DAT3:
>          break;
> +    case VC_EQC_CWATCH_DAT0:
> +        /* writing to DATA0 triggers the cache write */
> +        xive->regs[reg] = val;
> +        pnv_xive_end_update(xive);
> +        break;
> +    case VC_EQC_SCRUB_MASK:
>      case VC_EQC_SCRUB_TRIG:
> -        pnv_xive_end_update(xive, GETFIELD(VC_SCRUB_BLOCK_ID, val),
> -                            GETFIELD(VC_SCRUB_OFFSET, val));
> +        /*
> +         * The scrubbing registers flush the cache in RAM and can also
> +         * invalidate.
> +         */
>          break;
>  
> -    case PC_VPC_SCRUB_MASK:
>      case PC_VPC_CWATCH_SPEC:
> -    case PC_VPC_CWATCH_DAT0 ... PC_VPC_CWATCH_DAT7:
> +        val &= ~PC_VPC_CWATCH_CONFLICT; /* HW resets this bit */
> +        break;
> +    case PC_VPC_CWATCH_DAT1 ... PC_VPC_CWATCH_DAT7:
>          break;
> +    case PC_VPC_CWATCH_DAT0:
> +        /* writing to DATA0 triggers the cache write */
> +        xive->regs[reg] = val;
> +        pnv_xive_nvt_update(xive);
> +        break;
> +    case PC_VPC_SCRUB_MASK:
>      case PC_VPC_SCRUB_TRIG:
> -        pnv_xive_nvt_update(xive, GETFIELD(PC_SCRUB_BLOCK_ID, val),
> -                           GETFIELD(PC_SCRUB_OFFSET, val));
> +        /*
> +         * The scrubbing registers flush the cache in RAM and can also
> +         * invalidate.
> +         */
>          break;
>  
>  
> @@ -1022,15 +1075,6 @@ static uint64_t pnv_xive_ic_reg_read(void *opaque, hwaddr offset, unsigned size)
>      case PC_GLOBAL_CONFIG:
>  
>      case PC_VPC_SCRUB_MASK:
> -    case PC_VPC_CWATCH_SPEC:
> -    case PC_VPC_CWATCH_DAT0:
> -    case PC_VPC_CWATCH_DAT1:
> -    case PC_VPC_CWATCH_DAT2:
> -    case PC_VPC_CWATCH_DAT3:
> -    case PC_VPC_CWATCH_DAT4:
> -    case PC_VPC_CWATCH_DAT5:
> -    case PC_VPC_CWATCH_DAT6:
> -    case PC_VPC_CWATCH_DAT7:
>  
>      case VC_GLOBAL_CONFIG:
>      case VC_AIB_TX_ORDER_TAG2:
> @@ -1043,12 +1087,6 @@ static uint64_t pnv_xive_ic_reg_read(void *opaque, hwaddr offset, unsigned size)
>      case VC_IRQ_CONFIG_IPI_CASC:
>  
>      case VC_EQC_SCRUB_MASK:
> -    case VC_EQC_CWATCH_DAT0:
> -    case VC_EQC_CWATCH_DAT1:
> -    case VC_EQC_CWATCH_DAT2:
> -    case VC_EQC_CWATCH_DAT3:
> -
> -    case VC_EQC_CWATCH_SPEC:
>      case VC_IVC_SCRUB_MASK:
>      case VC_SBC_CONFIG:
>      case VC_AT_MACRO_KILL_MASK:
> @@ -1080,6 +1118,38 @@ static uint64_t pnv_xive_ic_reg_read(void *opaque, hwaddr offset, unsigned size)
>      /*
>       * XIVE PC & VC cache updates for EAS, NVT and END
>       */
> +    case VC_EQC_CWATCH_SPEC:
> +        xive->regs[reg] = ~(VC_EQC_CWATCH_FULL | VC_EQC_CWATCH_CONFLICT);
> +        val = xive->regs[reg];
> +        break;
> +    case VC_EQC_CWATCH_DAT0:
> +        /*
> +         * Load DATA registers from cache with data requested by the
> +         * SPEC register
> +         */
> +        pnv_xive_end_cache_load(xive);
> +        val = xive->regs[reg];
> +        break;
> +    case VC_EQC_CWATCH_DAT1 ... VC_EQC_CWATCH_DAT3:
> +        val = xive->regs[reg];
> +        break;
> +
> +    case PC_VPC_CWATCH_SPEC:
> +        xive->regs[reg] = ~(PC_VPC_CWATCH_FULL | PC_VPC_CWATCH_CONFLICT);
> +        val = xive->regs[reg];
> +        break;
> +    case PC_VPC_CWATCH_DAT0:
> +        /*
> +         * Load DATA registers from cache with data requested by the
> +         * SPEC register
> +         */
> +        pnv_xive_nvt_cache_load(xive);
> +        val = xive->regs[reg];
> +        break;
> +    case PC_VPC_CWATCH_DAT1 ... PC_VPC_CWATCH_DAT7:
> +        val = xive->regs[reg];
> +        break;
> +
>      case PC_VPC_SCRUB_TRIG:
>      case VC_IVC_SCRUB_TRIG:
>      case VC_EQC_SCRUB_TRIG:

-- 
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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