[kvm-unit-tests PATCH v4 3/9] s390x: interrupt registration

[Pierre Morel <pmorel@linux.ibm.com>]

Define two functions to register and to unregister a call back for IO
Interrupt handling.

Per default we keep the old behavior, so does a successful unregister
of the callback.

Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
---
 lib/s390x/interrupt.c | 23 ++++++++++++++++++++++-
 lib/s390x/interrupt.h |  7 +++++++
 2 files changed, 29 insertions(+), 1 deletion(-)
 create mode 100644 lib/s390x/interrupt.h

diff --git a/lib/s390x/interrupt.c b/lib/s390x/interrupt.c
index 05f30be..b70aafd 100644
--- a/lib/s390x/interrupt.c
+++ b/lib/s390x/interrupt.c
@@ -10,9 +10,9 @@
  * under the terms of the GNU Library General Public License version 2.
  */
 #include <libcflat.h>
-#include <asm/interrupt.h>
 #include <asm/barrier.h>
 #include <sclp.h>
+#include <interrupt.h>
 
 static bool pgm_int_expected;
 static bool ext_int_expected;
@@ -141,12 +141,33 @@ void handle_mcck_int(void)
 		     lc->mcck_old_psw.addr);
 }
 
+static void (*io_int_func)(void);
+
 void handle_io_int(void)
 {
+	if (*io_int_func)
+		return (*io_int_func)();
+
 	report_abort("Unexpected io interrupt: at %#lx",
 		     lc->io_old_psw.addr);
 }
 
+int register_io_int_func(void (*f)(void))
+{
+	if (io_int_func)
+		return -1;
+	io_int_func = f;
+	return 0;
+}
+
+int unregister_io_int_func(void (*f)(void))
+{
+	if (io_int_func != f)
+		return -1;
+	io_int_func = NULL;
+	return 0;
+}
+
 void handle_svc_int(void)
 {
 	report_abort("Unexpected supervisor call interrupt: at %#lx",
diff --git a/lib/s390x/interrupt.h b/lib/s390x/interrupt.h
new file mode 100644
index 0000000..e945ef7
--- /dev/null
+++ b/lib/s390x/interrupt.h
@@ -0,0 +1,7 @@
+#ifndef __INTERRUPT_H
+#include <asm/interrupt.h>
+
+int register_io_int_func(void (*f)(void));
+int unregister_io_int_func(void (*f)(void));
+
+#endif
-- 
2.17.0