commit 2948c1fb6b8d806d92394ec358e6ed727e946df9
author Bibo Mao <maobibo@loongson.cn> Fri Jul 07 17:15:57 2023 +0800
committer Song Gao <gaosong@loongson.cn> Thu Aug 24 11:17:59 2023 +0800
tree d8797b8cfa3c65663bc57f255c7298fb3df8895b
parent 14f21f673a01cf3efa22a70256947fb9b6bbfdfa

hw/intc/loongarch_pch: fix edge triggered irq handling

For edge triggered irq, qemu_irq_pulse is used to inject irq. It will
set irq with high level and low level soon to simluate pulse irq.

For edge triggered irq, irq is injected and set as pending at rising
level, do not clear irq at lowering level. LoongArch pch interrupt will
clear irq for lowering level irq, there will be problem. ACPI ged deivce
is edge-triggered irq, it is used for cpu/memory hotplug.

This patch fixes memory hotplug issue on LoongArch virt machine.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Reviewed-by: Song Gao <gaosong@loongson.cn>
Message-Id: <20230707091557.1474790-1-maobibo@loongson.cn>
Signed-off-by: Song Gao <gaosong@loongson.cn>

hw/intc/loongarch_pch_pic.c

diff --git a/hw/intc/loongarch_pch_pic.c b/hw/intc/loongarch_pch_pic.c
index 9208fc4..6aa4cad 100644
--- a/hw/intc/loongarch_pch_pic.c
+++ b/hw/intc/loongarch_pch_pic.c
@@ -30,7 +30,11 @@
             qemu_set_irq(s->parent_irq[s->htmsi_vector[irq]], 1);
         }
     } else {
-        val = mask & s->intisr;
+        /*
+         * intirr means requested pending irq
+         * do not clear pending irq for edge-triggered on lowering edge
+         */
+        val = mask & s->intisr & ~s->intirr;
         if (val) {
             irq = ctz64(val);
             s->intisr &= ~MAKE_64BIT_MASK(irq, 1);
@@ -51,6 +55,7 @@
         /* Edge triggered */
         if (level) {
             if ((s->last_intirr & mask) == 0) {
+                /* marked pending on a rising edge */
                 s->intirr |= mask;
             }
             s->last_intirr |= mask;