Re: [PATCH 04/50] ppc/xive2: Remote VSDs need to match on forwarding address

["Nicholas Piggin" <npiggin@gmail.com>]

On Mon May 12, 2025 at 1:10 PM AEST, Nicholas Piggin wrote:
> From: Michael Kowal <kowal@linux.ibm.com>
>
> In a multi chip environment there will be remote/forwarded VSDs.  The check
> to find a matching INT controller (XIVE) of the remote block number was
> checking the INTs chip number.  Block numbers are not tied to a chip number.
> The matching remote INT is the one that matches the forwarded VSD address
> with VSD types associated MMIO BAR.

Reviewed-by: Nicholas Piggin <npiggin@gmail.com>

>
> Signed-off-by: Michael Kowal <kowal@linux.ibm.com>
> ---
>  hw/intc/pnv_xive2.c | 25 +++++++++++++++++--------
>  1 file changed, 17 insertions(+), 8 deletions(-)
>
> diff --git a/hw/intc/pnv_xive2.c b/hw/intc/pnv_xive2.c
> index d1713b406c..30b4ab2efe 100644
> --- a/hw/intc/pnv_xive2.c
> +++ b/hw/intc/pnv_xive2.c
> @@ -102,12 +102,10 @@ static uint32_t pnv_xive2_block_id(PnvXive2 *xive)
>  }
>  
>  /*
> - * Remote access to controllers. HW uses MMIOs. For now, a simple scan
> - * of the chips is good enough.
> - *
> - * TODO: Block scope support
> + * Remote access to INT controllers. HW uses MMIOs(?). For now, a simple
> + * scan of all the chips INT controller is good enough.
>   */
> -static PnvXive2 *pnv_xive2_get_remote(uint8_t blk)
> +static PnvXive2 *pnv_xive2_get_remote(uint32_t vsd_type, hwaddr fwd_addr)
>  {
>      PnvMachineState *pnv = PNV_MACHINE(qdev_get_machine());
>      int i;
> @@ -116,10 +114,22 @@ static PnvXive2 *pnv_xive2_get_remote(uint8_t blk)
>          Pnv10Chip *chip10 = PNV10_CHIP(pnv->chips[i]);
>          PnvXive2 *xive = &chip10->xive;
>  
> -        if (pnv_xive2_block_id(xive) == blk) {
> +        /*
> +         * Is this the XIVE matching the forwarded VSD address is for this
> +         * VSD type
> +         */
> +        if ((vsd_type == VST_ESB   && fwd_addr == xive->esb_base) ||
> +            (vsd_type == VST_END   && fwd_addr == xive->end_base)  ||
> +            ((vsd_type == VST_NVP ||
> +              vsd_type == VST_NVG) && fwd_addr == xive->nvpg_base) ||
> +            (vsd_type == VST_NVC   && fwd_addr == xive->nvc_base)) {
>              return xive;
>          }
>      }
> +
> +    qemu_log_mask(LOG_GUEST_ERROR,
> +                 "XIVE: >>>>> pnv_xive2_get_remote() vsd_type %u  fwd_addr 0x%lX NOT FOUND\n",
> +                 vsd_type, fwd_addr);
>      return NULL;
>  }
>  
> @@ -252,8 +262,7 @@ static uint64_t pnv_xive2_vst_addr(PnvXive2 *xive, uint32_t type, uint8_t blk,
>  
>      /* Remote VST access */
>      if (GETFIELD(VSD_MODE, vsd) == VSD_MODE_FORWARD) {
> -        xive = pnv_xive2_get_remote(blk);
> -
> +        xive = pnv_xive2_get_remote(type, (vsd & VSD_ADDRESS_MASK));
>          return xive ? pnv_xive2_vst_addr(xive, type, blk, idx) : 0;
>      }
>