Re: [PATCH 42/50] ppc/xive: Redistribute phys after pulling of pool context

[Mike Kowal]

On 5/11/2025 10:10 PM, Nicholas Piggin wrote:
> After pulling the pool context, if a pool irq had been presented and
> was cleared in the process, there could be a pending irq in phys that
> should be presented. Process the phys irq ring after pulling pool ring
> to catch this case and avoid losing irqs.

Reviewed-by: Michael Kowal<kowal@linux.ibm.com>

Thanks,  MAK
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>   hw/intc/xive.c  |  3 +++
>   hw/intc/xive2.c | 16 ++++++++++++++--
>   2 files changed, 17 insertions(+), 2 deletions(-)
>
> diff --git a/hw/intc/xive.c b/hw/intc/xive.c
> index 81af59f0ec..aeca66e56e 100644
> --- a/hw/intc/xive.c
> +++ b/hw/intc/xive.c
> @@ -320,6 +320,9 @@ static uint64_t xive_tm_pull_pool_ctx(XivePresenter *xptr, 
> XiveTCTX *tctx,
>   
>       xive_tctx_reset_signal(tctx, TM_QW1_OS);
>       xive_tctx_reset_signal(tctx, TM_QW2_HV_POOL);
> +    /* Re-check phys for interrupts if pool was disabled */
> +    xive_tctx_pipr_recompute_from_ipb(tctx, TM_QW3_HV_PHYS);
> +
>       return qw2w2;
>   }
>   
> diff --git a/hw/intc/xive2.c b/hw/intc/xive2.c
> index aeeb901b6a..917ecbaae4 100644
> --- a/hw/intc/xive2.c
> +++ b/hw/intc/xive2.c
> @@ -683,6 +683,8 @@ static void xive2_redistribute(Xive2Router *xrtr, XiveTCTX 
> *tctx, uint8_t ring)
>       xive_tctx_reset_signal(tctx, ring);
>   }
>   
> +static void xive2_tctx_process_pending(XiveTCTX *tctx, uint8_t sig_ring);
> +
>   static uint64_t xive2_tm_pull_ctx(XivePresenter *xptr, XiveTCTX *tctx,
>                                     hwaddr offset, unsigned size, uint8_t ring)
>   {
> @@ -739,6 +741,18 @@ static uint64_t xive2_tm_pull_ctx(XivePresenter *xptr, 
> XiveTCTX *tctx,
>           }
>       }
>   
> +    if (ring == TM_QW2_HV_POOL) {
> +        /* Re-check phys for interrupts if pool was disabled */
> +        nsr = tctx->regs[TM_QW3_HV_PHYS + TM_NSR];
> +        if (xive_nsr_indicates_exception(TM_QW3_HV_PHYS, nsr)) {
> +            /* Ring must be PHYS because POOL would have been redistributed */
> +            g_assert(xive_nsr_exception_ring(TM_QW3_HV_PHYS, nsr) ==
> +                                                           TM_QW3_HV_PHYS);
> +        } else {
> +            xive2_tctx_process_pending(tctx, TM_QW3_HV_PHYS);
> +        }
> +    }
> +
>       if (xive2_router_get_config(xrtr) & XIVE2_VP_SAVE_RESTORE && do_save) {
>           xive2_tctx_save_ctx(xrtr, tctx, ring, nvp_blk, nvp_idx);
>       }
> @@ -925,8 +939,6 @@ static uint8_t xive2_tctx_restore_ctx(Xive2Router *xrtr, 
> XiveTCTX *tctx,
>       return cppr;
>   }
>   
> -static void xive2_tctx_process_pending(XiveTCTX *tctx, uint8_t sig_ring);
> -
>   static void xive2_tctx_need_resend(Xive2Router *xrtr, XiveTCTX *tctx,
>                                      uint8_t nvp_blk, uint32_t nvp_idx,
>                                      bool do_restore)