tests/device-plug: Add a simple PCI unplug request test

The issue with testing asynchronous unplug requests it that they usually
require a running guest to handle the request. However, to test if
unplug of PCI devices works, we can apply a nice little trick on some
architectures:

On system reset, x86 ACPI, s390x and spapr will perform the unplug,
resulting in the device of interest to get deleted and a DEVICE_DELETED
event getting sent.

On s390x, we still get a warning
    qemu-system-s390x: -device virtio-mouse-pci,id=dev0:
    warning: Plugging a PCI/zPCI device without the 'zpci' CPU feature
    enabled; the guest will not be able to see/use this device

This will be fixed soon, when we enable the zpci CPU feature always
(Conny already has a patch for this queued).

Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: Collin Walling <walling@linux.ibm.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: David Hildenbrand <david@redhat.com>
Message-Id: <20190218092202.26683-4-david@redhat.com>
Acked-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

1 files changed, 93 insertions, 0 deletions

diff --git a/tests/device-plug-test.c b/tests/device-plug-test.c
new file mode 100644
index 0000000000..cd9ada539d
--- /dev/null
+++ b/tests/device-plug-test.c
@@ -0,0 +1,93 @@
+/*
+ * QEMU device plug/unplug handling
+ *
+ * Copyright (C) 2019 Red Hat Inc.
+ *
+ * Authors:
+ *  David Hildenbrand <david@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "libqtest.h"
+#include "qapi/qmp/qdict.h"
+#include "qapi/qmp/qstring.h"
+
+static void device_del_request(QTestState *qtest, const char *id)
+{
+    QDict *resp;
+
+    resp = qtest_qmp(qtest,
+                     "{'execute': 'device_del', 'arguments': { 'id': %s } }",
+                     id);
+    g_assert(qdict_haskey(resp, "return"));
+    qobject_unref(resp);
+}
+
+static void system_reset(QTestState *qtest)
+{
+    QDict *resp;
+
+    resp = qtest_qmp(qtest, "{'execute': 'system_reset'}");
+    g_assert(qdict_haskey(resp, "return"));
+    qobject_unref(resp);
+}
+
+static void wait_device_deleted_event(QTestState *qtest, const char *id)
+{
+    QDict *resp, *data;
+    QString *qstr;
+
+    /*
+     * Other devices might get removed along with the removed device. Skip
+     * these. The device of interest will be the last one.
+     */
+    for (;;) {
+        resp = qtest_qmp_eventwait_ref(qtest, "DEVICE_DELETED");
+        data = qdict_get_qdict(resp, "data");
+        if (!data || !qdict_get(data, "device")) {
+            qobject_unref(resp);
+            continue;
+        }
+        qstr = qobject_to(QString, qdict_get(data, "device"));
+        g_assert(qstr);
+        if (!strcmp(qstring_get_str(qstr), id)) {
+            qobject_unref(resp);
+            break;
+        }
+        qobject_unref(resp);
+    }
+}
+
+static void test_pci_unplug_request(void)
+{
+    QTestState *qtest = qtest_initf("-device virtio-mouse-pci,id=dev0");
+
+    /*
+     * Request device removal. As the guest is not running, the request won't
+     * be processed. However during system reset, the removal will be
+     * handled, removing the device.
+     */
+    device_del_request(qtest, "dev0");
+    system_reset(qtest);
+    wait_device_deleted_event(qtest, "dev0");
+
+    qtest_quit(qtest);
+}
+
+int main(int argc, char **argv)
+{
+    g_test_init(&argc, &argv, NULL);
+
+    /*
+     * We need a system that will process unplug requests during system resets
+     * and does not do PCI surprise removal. This holds for x86 ACPI,
+     * s390x and spapr.
+     */
+    qtest_add_func("/device-plug/pci-unplug-request",
+                   test_pci_unplug_request);
+
+    return g_test_run();
+}