[Qemu-devel] [RFC 05/14] Add vhost-user backend to virtio-input-host

[marcandre.lureau@redhat.com]

From: Marc-André Lureau <marcandre.lureau@redhat.com>

Learn to use a vhost-user as a virtio-input backend. Usage:

-object vhost-user-backend,id=vuid -device virtio-input-host-pci,vhost-user=vuid

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 hw/input/virtio-input-host.c     | 67 ++++++++++++++++++++++++++++++++++------
 hw/input/virtio-input.c          |  4 +++
 hw/virtio/virtio-pci.c           |  5 +++
 include/hw/virtio/virtio-input.h |  2 ++
 4 files changed, 69 insertions(+), 9 deletions(-)

diff --git a/hw/input/virtio-input-host.c b/hw/input/virtio-input-host.c
index cb79e80..c2c48bd 100644
--- a/hw/input/virtio-input-host.c
+++ b/hw/input/virtio-input-host.c
@@ -95,20 +95,14 @@ static void virtio_input_abs_config(VirtIOInputHost *vih, int axis)
     virtio_input_add_config(VIRTIO_INPUT(vih), &config);
 }
 
-static void virtio_input_host_realize(DeviceState *dev, Error **errp)
+static void virtio_input_evdev_init(VirtIOInputHost *vih, Error **errp)
 {
-    VirtIOInputHost *vih = VIRTIO_INPUT_HOST(dev);
-    VirtIOInput *vinput = VIRTIO_INPUT(dev);
+    VirtIOInput *vinput = VIRTIO_INPUT(vih);
     virtio_input_config id, *abs;
     struct input_id ids;
     int rc, ver, i, axis;
     uint8_t byte;
 
-    if (!vih->evdev) {
-        error_setg(errp, "evdev property is required");
-        return;
-    }
-
     vih->fd = open(vih->evdev, O_RDWR);
     if (vih->fd < 0)  {
         error_setg_file_open(errp, errno, vih->evdev);
@@ -175,7 +169,34 @@ static void virtio_input_host_realize(DeviceState *dev, Error **errp)
 err_close:
     close(vih->fd);
     vih->fd = -1;
-    return;
+}
+
+static void virtio_input_host_realize(DeviceState *dev, Error **errp)
+{
+    VirtIOInputHost *vih = VIRTIO_INPUT_HOST(dev);
+    VirtIOInput *vinput = VIRTIO_INPUT(vih);
+
+    if (!!vih->evdev + !!vinput->vhost != 1) {
+        error_setg(errp, "'evdev' or 'vhost-user' property is required");
+        return;
+    }
+
+    if (vih->evdev) {
+        virtio_input_evdev_init(vih, errp);
+    } else {
+        virtio_input_config *config;
+        int i, ret;
+
+        ret = vhost_user_input_get_config(&vinput->vhost->dev, &config);
+        if (ret < 0) {
+            error_setg(errp, "failed to get input config");
+            return;
+        }
+        for (i = 0; i < ret; i++) {
+            virtio_input_add_config(vinput, &config[i]);
+        }
+        g_free(config);
+    }
 }
 
 static void virtio_input_host_unrealize(DeviceState *dev, Error **errp)
@@ -210,6 +231,15 @@ static void virtio_input_host_handle_status(VirtIOInput *vinput,
     }
 }
 
+static void virtio_input_host_change_active(VirtIOInput *vinput)
+{
+    if (vinput->active) {
+        vhost_user_backend_start(vinput->vhost);
+    } else {
+        vhost_user_backend_stop(vinput->vhost);
+    }
+}
+
 static const VMStateDescription vmstate_virtio_input_host = {
     .name = "virtio-input-host",
     .unmigratable = 1,
@@ -230,6 +260,19 @@ static void virtio_input_host_class_init(ObjectClass *klass, void *data)
     vic->realize       = virtio_input_host_realize;
     vic->unrealize     = virtio_input_host_unrealize;
     vic->handle_status = virtio_input_host_handle_status;
+    vic->change_active = virtio_input_host_change_active;
+}
+
+static void virtio_input_host_user_is_busy(Object *obj, const char *name,
+                                           Object *val, Error **errp)
+{
+    VirtIOInput *vinput = VIRTIO_INPUT(obj);
+
+    if (vinput->vhost) {
+        error_setg(errp, "can't use already busy vhost-user");
+    } else {
+        qdev_prop_allow_set_link_before_realize(obj, name, val, errp);
+    }
 }
 
 static void virtio_input_host_init(Object *obj)
@@ -237,6 +280,12 @@ static void virtio_input_host_init(Object *obj)
     VirtIOInput *vinput = VIRTIO_INPUT(obj);
 
     virtio_input_init_config(vinput, virtio_input_host_config);
+
+    object_property_add_link(obj, "vhost-user", TYPE_VHOST_USER_BACKEND,
+                             (Object **)&vinput->vhost,
+                             virtio_input_host_user_is_busy,
+                             OBJ_PROP_LINK_UNREF_ON_RELEASE,
+                             &error_abort);
 }
 
 static const TypeInfo virtio_input_host_info = {
diff --git a/hw/input/virtio-input.c b/hw/input/virtio-input.c
index f59749a..3c9ac46 100644
--- a/hw/input/virtio-input.c
+++ b/hw/input/virtio-input.c
@@ -280,6 +280,10 @@ static void virtio_input_device_realize(DeviceState *dev, Error **errp)
     vinput->evt = virtio_add_queue(vdev, 64, virtio_input_handle_evt);
     vinput->sts = virtio_add_queue(vdev, 64, virtio_input_handle_sts);
 
+    if (vinput->vhost) {
+        vhost_user_backend_dev_init(vinput->vhost, vdev, 2, errp);
+    }
+
     register_savevm(dev, "virtio-input", -1, VIRTIO_INPUT_VM_VERSION,
                     virtio_input_save, virtio_input_load, vinput);
 }
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index bfedbbf..0a14fd4 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -2454,6 +2454,11 @@ static void virtio_host_initfn(Object *obj)
 
     virtio_instance_init_common(obj, &dev->vdev, sizeof(dev->vdev),
                                 TYPE_VIRTIO_INPUT_HOST);
+
+    /* could eventually be included in qdev_alias_all_properties? */
+    object_property_add_alias(obj, "vhost-user",
+                              OBJECT(&dev->vdev), "vhost-user",
+                              &error_abort);
 }
 
 static const TypeInfo virtio_host_pci_info = {
diff --git a/include/hw/virtio/virtio-input.h b/include/hw/virtio/virtio-input.h
index bddbd4b..05694b1 100644
--- a/include/hw/virtio/virtio-input.h
+++ b/include/hw/virtio/virtio-input.h
@@ -2,6 +2,7 @@
 #define _QEMU_VIRTIO_INPUT_H
 
 #include "ui/input.h"
+#include "sysemu/vhost-user-backend.h"
 
 /* ----------------------------------------------------------------- */
 /* virtio input protocol                                             */
@@ -66,6 +67,7 @@ struct VirtIOInput {
     uint32_t                          qindex, qsize;
 
     bool                              active;
+    VhostUserBackend                  *vhost;
 };
 
 struct VirtIOInputClass {
-- 
2.7.4