[RFC,v2] tests/qtest: attempt to enable tests for virtio-gpio (!working)

diff --git a/tests/qtest/libqos/virtio-gpio.h b/tests/qtest/libqos/virtio-gpio.h
new file mode 100644
index 0000000000..abe6967ae9
--- /dev/null
+++ b/tests/qtest/libqos/virtio-gpio.h
@@ -0,0 +1,34 @@ 
+/*
+ * virtio-gpio structures
+ *
+ * Copyright (c) 2022 Linaro Ltd
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef TESTS_LIBQOS_VIRTIO_GPIO_H
+#define TESTS_LIBQOS_VIRTIO_GPIO_H
+
+#include "qgraph.h"
+#include "virtio.h"
+#include "virtio-pci.h"
+
+typedef struct QVhostUserGPIO QVhostUserGPIO;
+typedef struct QVhostUserGPIOPCI QVhostUserGPIOPCI;
+typedef struct QVhostUserGPIODevice QVhostUserGPIODevice;
+
+struct QVhostUserGPIO {
+    QVirtioDevice *vdev;
+};
+
+struct QVhostUserGPIOPCI {
+    QVirtioPCIDevice pci_vdev;
+    QVhostUserGPIO gpio;
+};
+
+struct QVhostUserGPIODevice {
+    QOSGraphObject obj;
+    QVhostUserGPIO gpio;
+};
+
+#endif
diff --git a/tests/qtest/libqos/virtio-gpio.c b/tests/qtest/libqos/virtio-gpio.c
new file mode 100644
index 0000000000..a12671c8b1
--- /dev/null
+++ b/tests/qtest/libqos/virtio-gpio.c
@@ -0,0 +1,98 @@ 
+/*
+ * virtio-gpio nodes for testing
+ *
+ * Copyright (c) 2022 Linaro Ltd
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "libqtest.h"
+#include "qemu/module.h"
+#include "qgraph.h"
+#include "virtio-gpio.h"
+
+static void *qvirtio_gpio_get_driver(QVhostUserGPIO *v_gpio,
+                                     const char *interface)
+{
+    if (!g_strcmp0(interface, "vhost-user-gpio")) {
+        return v_gpio;
+    }
+    if (!g_strcmp0(interface, "virtio")) {
+        return v_gpio->vdev;
+    }
+
+    fprintf(stderr, "%s not present in virtio-gpio-device\n", interface);
+    g_assert_not_reached();
+}
+
+static void *qvirtio_gpio_device_get_driver(void *object,
+                                              const char *interface)
+{
+    QVhostUserGPIODevice *v_gpio = object;
+    return qvirtio_gpio_get_driver(&v_gpio->gpio, interface);
+}
+
+static void *virtio_gpio_device_create(void *virtio_dev,
+                                         QGuestAllocator *t_alloc,
+                                         void *addr)
+{
+    QVhostUserGPIODevice *virtio_device = g_new0(QVhostUserGPIODevice, 1);
+    QVhostUserGPIO *interface = &virtio_device->gpio;
+
+    interface->vdev = virtio_dev;
+
+    virtio_device->obj.get_driver = qvirtio_gpio_device_get_driver;
+
+    return &virtio_device->obj;
+}
+
+/* virtio-gpio-pci */
+static void *qvirtio_gpio_pci_get_driver(void *object, const char *interface)
+{
+    QVhostUserGPIOPCI *v_gpio = object;
+    if (!g_strcmp0(interface, "pci-device")) {
+        return v_gpio->pci_vdev.pdev;
+    }
+    return qvirtio_gpio_get_driver(&v_gpio->gpio, interface);
+}
+
+static void *virtio_gpio_pci_create(void *pci_bus, QGuestAllocator *t_alloc,
+                                      void *addr)
+{
+    QVhostUserGPIOPCI *virtio_spci = g_new0(QVhostUserGPIOPCI, 1);
+    QVhostUserGPIO *interface = &virtio_spci->gpio;
+    QOSGraphObject *obj = &virtio_spci->pci_vdev.obj;
+
+    virtio_pci_init(&virtio_spci->pci_vdev, pci_bus, addr);
+    interface->vdev = &virtio_spci->pci_vdev.vdev;
+
+    obj->get_driver = qvirtio_gpio_pci_get_driver;
+
+    return obj;
+}
+
+static void virtio_gpio_register_nodes(void)
+{
+    QPCIAddress addr = {
+        .devfn = QPCI_DEVFN(4, 0),
+    };
+
+    QOSGraphEdgeOptions edge_opts = { };
+
+    /* vhost-user-gpio-device */
+    edge_opts.extra_device_opts = "id=gpio0,chardev=chr-vhost-user-test";
+    qos_node_create_driver("vhost-user-gpio-device",
+                            virtio_gpio_device_create);
+    qos_node_consumes("vhost-user-gpio-device", "virtio-bus", &edge_opts);
+    qos_node_produces("vhost-user-gpio-device", "vhost-user-gpio");
+
+    /* virtio-gpio-pci */
+    edge_opts.extra_device_opts = "id=gpio0,addr=04.0,chardev=chr-vhost-user-test";
+    add_qpci_address(&edge_opts, &addr);
+    qos_node_create_driver("vhost-user-gpio-pci", virtio_gpio_pci_create);
+    qos_node_consumes("vhost-user-gpio-pci", "pci-bus", &edge_opts);
+    qos_node_produces("vhost-user-gpio-pci", "vhost-user-gpio");
+}
+
+libqos_init(virtio_gpio_register_nodes);
diff --git a/tests/qtest/vhost-user-test.c b/tests/qtest/vhost-user-test.c
index ee30f54796..836f30a4be 100644
--- a/tests/qtest/vhost-user-test.c
+++ b/tests/qtest/vhost-user-test.c
@@ -55,6 +55,7 @@ 
 #define VHOST_USER_PROTOCOL_F_MQ 0
 #define VHOST_USER_PROTOCOL_F_LOG_SHMFD 1
 #define VHOST_USER_PROTOCOL_F_CROSS_ENDIAN   6
+#define VHOST_USER_PROTOCOL_F_CONFIG 9
 
 #define VHOST_LOG_PAGE 0x1000
 
@@ -78,6 +79,8 @@  typedef enum VhostUserRequest {
     VHOST_USER_SET_PROTOCOL_FEATURES = 16,
     VHOST_USER_GET_QUEUE_NUM = 17,
     VHOST_USER_SET_VRING_ENABLE = 18,
+    VHOST_USER_GET_CONFIG = 24,
+    VHOST_USER_SET_CONFIG = 25,
     VHOST_USER_MAX
 } VhostUserRequest;
 
@@ -137,6 +140,7 @@  enum {
 
 enum {
     VHOST_USER_NET,
+    VHOST_USER_GPIO,
 };
 
 typedef struct TestServer {
@@ -194,6 +198,19 @@  static void append_vhost_net_opts(TestServer *s, GString *cmd_line,
                            chr_opts, s->chr_name);
 }
 
+/*
+ * For GPIO there are no other magic devices we need to add (like
+ * block or netdev) so all we need to worry about is the vhost-user
+ * chardev socket.
+ */
+static void append_vhost_gpio_opts(TestServer *s, GString *cmd_line,
+                             const char *chr_opts)
+{
+    g_string_append_printf(cmd_line, QEMU_CMD_CHR,
+                           s->chr_name, s->socket_path,
+                           chr_opts);
+}
+
 static void append_mem_opts(TestServer *server, GString *cmd_line,
                             int size, enum test_memfd memfd)
 {
@@ -426,6 +443,8 @@  static void chr_read(void *opaque, const uint8_t *buf, int size)
         break;
 
     default:
+        g_test_message("unhandled vhost-user message: %d", msg.request);
+        g_test_fail();
         break;
     }
 
@@ -1014,3 +1033,44 @@  static void register_vhost_user_test(void)
                  test_multiqueue, &opts);
 }
 libqos_init(register_vhost_user_test);
+
+/*
+ * This stub can't handle all the message types but we should reply
+ * that we support VHOST_USER_PROTOCOL_F_CONFIG as gpio would use it
+ * talking to a read vhost-user daemon.
+ */
+static void vu_gpio_get_protocol_features(TestServer *s, CharBackend *chr,
+        VhostUserMsg *msg)
+{
+    /* send back features to qemu */
+    msg->flags |= VHOST_USER_REPLY_MASK;
+    msg->size = sizeof(m.payload.u64);
+    msg->payload.u64 = 1ULL << VHOST_USER_PROTOCOL_F_LOG_SHMFD;
+    msg->payload.u64 |= 1ULL << VHOST_USER_PROTOCOL_F_CONFIG;
+
+    qemu_chr_fe_write_all(chr, (uint8_t *)msg, VHOST_USER_HDR_SIZE + msg->size);
+}
+
+static struct vhost_user_ops g_vu_gpio_ops = {
+    .type = VHOST_USER_GPIO,
+
+    .append_opts = append_vhost_gpio_opts,
+
+    .set_features = vu_net_set_features,
+    .get_protocol_features = vu_gpio_get_protocol_features,
+};
+
+static void register_vhost_gpio_test(void)
+{
+    QOSGraphTestOptions opts = {
+        .before = vhost_user_test_setup,
+        .subprocess = true,
+        .arg = &g_vu_gpio_ops,
+    };
+
+    qemu_add_opts(&qemu_chardev_opts);
+
+    qos_add_test("read-guest-mem/memfile",
+                 "vhost-user-gpio", test_read_guest_mem, &opts);
+}
+libqos_init(register_vhost_gpio_test);
diff --git a/tests/qtest/libqos/meson.build b/tests/qtest/libqos/meson.build
index 8c8ee15553..f581330d8b 100644
--- a/tests/qtest/libqos/meson.build
+++ b/tests/qtest/libqos/meson.build
@@ -42,6 +42,7 @@  libqos_srcs = files('../libqtest.c',
         'virtio-scsi.c',
         'virtio-serial.c',
         'virtio-iommu.c',
+        'virtio-gpio.c',
         'generic-pcihost.c',
 
         # qgraph machines: