ppc/xive: tctx_notify should clear the precluded interrupt

If CPPR is lowered to preclude the pending interrupt, NSR should be
cleared and the qemu_irq should be lowered. This avoids some cases
of supurious interrupts.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Reviewed-by: Glenn Miles <milesg@linux.ibm.com>
Reviewed-by: Michael Kowal <kowal@linux.ibm.com>
Reviewed-by: Caleb Schlossin <calebs@linux.ibm.com>
Tested-by: Gautam Menghani <gautam@linux.ibm.com>
Link: https://lore.kernel.org/qemu-devel/20250512031100.439842-14-npiggin@gmail.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>

diff --git a/hw/intc/xive.c b/hw/intc/xive.c
index bc829bebe9d068bbb022fa727f1807332ff71def..a0a60a24f510ade246dc8841328058a73d0a2071 100644 (file)
--- a/hw/intc/xive.c
+++ b/hw/intc/xive.c
@@ -110,6 +110,9 @@ void xive_tctx_notify(XiveTCTX *tctx, uint8_t ring, uint8_t group_level)
                                regs[TM_IPB], alt_regs[TM_PIPR],
                                alt_regs[TM_CPPR], alt_regs[TM_NSR]);
         qemu_irq_raise(xive_tctx_output(tctx, ring));
+    } else {
+        alt_regs[TM_NSR] = 0;
+        qemu_irq_lower(xive_tctx_output(tctx, ring));
     }
 }