QTest framework does not capture toggled irq line

[Gustavo Romero]

Hi folks,

I'm writing a test for a device that has one IRQ output line
that is toggled (raised then lowered) by the device to trigger
a CPU interrupt.

Afaics the QTest framework does not provide a way to capture
when an output line is raised because the API functions, e.g.
qtest_get_irq(), read the current state of the intercepted
IRQ lines, which is already low when the function is called,
since the line is toggled by the device.

I'd like to introduce a new API function to address this case,
called qtest_get_irq_trigger_counter():

diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
index 471529e6cc..9ed2a43155 100644
--- a/tests/qtest/libqtest.c
+++ b/tests/qtest/libqtest.c
@@ -79,6 +79,7 @@ struct QTestState
diff --git a/tests/qtest/libqtest.c b/tests/qtest/libqtest.c
index 471529e6cc..9ed2a43155 100644
--- a/tests/qtest/libqtest.c
+++ b/tests/qtest/libqtest.c
@@ -79,6 +79,7 @@ struct QTestState
     int expected_status;
     bool big_endian;
     bool irq_level[MAX_IRQ];
+    uint64_t irq_trigger_counter[MAX_IRQ];
     GString *rx;
     QTestTransportOps ops;
     GList *pending_events;
@@ -481,6 +482,7 @@ QTestState *qtest_init_without_qmp_handshake(const char 
*extra_args)
     s->rx = g_string_new("");
     for (i = 0; i < MAX_IRQ; i++) {
         s->irq_level[i] = false;
+        s->irq_trigger_counter[i] = 0;
     }
 
     /*
@@ -663,6 +665,7 @@ redo:
 
         if (strcmp(words[1], "raise") == 0) {
             s->irq_level[irq] = true;
+            s->irq_trigger_counter[irq]++;
         } else {
             s->irq_level[irq] = false;
         }
@@ -953,6 +956,14 @@ bool qtest_get_irq(QTestState *s, int num)
     return s->irq_level[num];
 }
 
+uint64_t qtest_get_irq_trigger_counter(QTestState *s, int irq_num)
+{
+    /* dummy operation in order to make sure irq is up to date */
+    qtest_inb(s, 0);
+
+    return s->irq_trigger_counter[irq_num];
+}
+
 void qtest_module_load(QTestState *s, const char *prefix, const char *libname)
 {
     qtest_sendf(s, "module_load %s %s\n", prefix, libname);
@@ -1693,6 +1704,7 @@ QTestState *qtest_inproc_init(QTestState **s, bool log, 
const char* arch,
     qts->wstatus = 0;
     for (int i = 0; i < MAX_IRQ; i++) {
         qts->irq_level[i] = false;
+        qts->irq_trigger_counter[i] = 0;
     }
 
     qtest_client_set_rx_handler(qts, qtest_client_inproc_recv_line);
diff --git a/tests/qtest/libqtest.h b/tests/qtest/libqtest.h
index e53e350e3a..0e763a4507 100644
--- a/tests/qtest/libqtest.h
+++ b/tests/qtest/libqtest.h
@@ -351,6 +351,16 @@ void qtest_module_load(QTestState *s, const char *prefix, 
const char *libname);
  */
 bool qtest_get_irq(QTestState *s, int num);
 
+
+/**
+ * qtest_get_irq_counter:
+ * @s: #QTestState instance to operate on.
+ * @irq_num: Interrupt to observe.
+ *
+ * Returns: The number of times @irq_num got triggered (raised).
+ */
+uint64_t qtest_get_irq_trigger_counter(QTestState *s, int irq_num);
+
 /**
  * qtest_irq_intercept_in:
  * @s: #QTestState instance to operate on.


This change addresses the current QTest limitation. Is it acceptable?


Cheers,
Gustavo