From e4065c7739c8ea3f6f88898295ed899a1059806e Mon Sep 17 00:00:00 2001
From: Greg Kurz <gkurz@redhat.com>
Date: Fri, 4 Dec 2020 15:08:00 -0500
Subject: [PATCH 02/14] ppc/spapr: re-assert IRQs during event-scan if there
 are pending

RH-Author: Greg Kurz <gkurz@redhat.com>
Message-id: <20201204150800.264829-3-gkurz@redhat.com>
Patchwork-id: 100216
O-Subject: [RHEL-8.4.0 qemu-kvm PATCH 2/2] ppc/spapr: re-assert IRQs during event-scan if there are pending
Bugzilla: 1901837
RH-Acked-by: Danilo de Paula <ddepaula@redhat.com>
RH-Acked-by: David Gibson <dgibson@redhat.com>
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>

From: Laurent Vivier <lvivier@redhat.com>

If we hotplug a CPU during the first second of the kernel boot,
the IRQ can be sent to the kernel while the RTAS event handler
is not installed. The event is queued, but the kernel doesn't
collect it and ignores the new CPU.

As the code relies on edge-triggered IRQ, we can re-assert it
during the event-scan RTAS call if there are still pending
events (as it is already done in check-exception).

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20201015210318.117386-1-lvivier@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
(cherry picked from commit dff669d6a15fb92b063cb5aa691b4bb498727404)
Signed-off-by: Greg Kurz <gkurz@redhat.com>
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
 hw/ppc/spapr_events.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/hw/ppc/spapr_events.c b/hw/ppc/spapr_events.c
index e355e000d07..15b92b63adb 100644
--- a/hw/ppc/spapr_events.c
+++ b/hw/ppc/spapr_events.c
@@ -692,10 +692,22 @@ static void event_scan(PowerPCCPU *cpu, SpaprMachineState *spapr,
                        target_ulong args,
                        uint32_t nret, target_ulong rets)
 {
+    int i;
     if (nargs != 4 || nret != 1) {
         rtas_st(rets, 0, RTAS_OUT_PARAM_ERROR);
         return;
     }
+
+    for (i = 0; i < EVENT_CLASS_MAX; i++) {
+        if (rtas_event_log_contains(EVENT_CLASS_MASK(i))) {
+            const SpaprEventSource *source =
+                spapr_event_sources_get_source(spapr->event_sources, i);
+
+            g_assert(source->enabled);
+            qemu_irq_pulse(spapr_qirq(spapr, source->irq));
+        }
+    }
+
     rtas_st(rets, 0, RTAS_OUT_NO_ERRORS_FOUND);
 }
 
-- 
2.27.0