Re: [PATCH v3 2/5] hw/intc/loongarch_pch_pic: Fix bugs for update_irq function

[Richard Henderson]

On 7/15/22 11:37, Xiaojuan Yang wrote:

Fix such errors:
1. We should not use 'unsigned long' type as argument when we use
find_first_bit(), and we use ctz64() to replace find_first_bit()
to fix this bug.
2. It is not standard to use '1ULL << irq' to generate a irq mask.
So, we replace it with 'MAKE_64BIT_MASK(irq, 1)'.

Fix coverity CID: 1489761 1489764 1489765

Signed-off-by: Xiaojuan Yang <yangxiaoj...@loongson.cn>
---
  hw/intc/loongarch_pch_pic.c | 18 +++++++++++-------
  1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/hw/intc/loongarch_pch_pic.c b/hw/intc/loongarch_pch_pic.c
index 3c9814a3b4..8fa64d2030 100644
--- a/hw/intc/loongarch_pch_pic.c
+++ b/hw/intc/loongarch_pch_pic.c
@@ -15,22 +15,26 @@

static void pch_pic_update_irq(LoongArchPCHPIC *s, uint64_t mask, int level)

  {
-    unsigned long val;
+    uint64_t val;
      int irq;

if (level) {

          val = mask & s->intirr & ~s->int_mask;
          if (val) {
-            irq = find_first_bit(&val, 64);
-            s->intisr |= 0x1ULL << irq;
-            qemu_set_irq(s->parent_irq[s->htmsi_vector[irq]], 1);
+            irq = ctz64(val);
+            if (irq < 64) {

This test is always true, provable by the val != 0 test just above.


r~

+                s->intisr |= MAKE_64BIT_MASK(irq, 1);
+                qemu_set_irq(s->parent_irq[s->htmsi_vector[irq]], 1);
+            }
          }
      } else {
          val = mask & s->intisr;
          if (val) {
-            irq = find_first_bit(&val, 64);
-            s->intisr &= ~(0x1ULL << irq);
-            qemu_set_irq(s->parent_irq[s->htmsi_vector[irq]], 0);
+            irq = ctz64(val);
+            if (irq < 64) {
+                s->intisr &= ~(MAKE_64BIT_MASK(irq, 1));
+                qemu_set_irq(s->parent_irq[s->htmsi_vector[irq]], 0);
+            }
          }
      }
  }