virtio-input: evdev passthrough

This allows to assign host input devices to the guest:

qemu -device virtio-input-host-pci,evdev=/dev/input/event<nr>

The guest gets exclusive access to the input device, so be careful
with assigning the keyboard if you have only one connected to your
machine.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 188 insertions, 0 deletions

diff --git a/hw/input/virtio-input-host.c b/hw/input/virtio-input-host.c
new file mode 100644
index 0000000000..f7e3d844e6
--- /dev/null
+++ b/hw/input/virtio-input-host.c
@@ -0,0 +1,188 @@
+/*
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * (at your option) any later version.  See the COPYING file in the
+ * top-level directory.
+ */
+
+#include "qemu-common.h"
+#include "qemu/sockets.h"
+
+#include "hw/qdev.h"
+#include "hw/virtio/virtio.h"
+#include "hw/virtio/virtio-input.h"
+
+#include "standard-headers/linux/input.h"
+
+/* ----------------------------------------------------------------- */
+
+static struct virtio_input_config virtio_input_host_config[] = {
+    { /* empty list */ },
+};
+
+static void virtio_input_host_event(void *opaque)
+{
+    VirtIOInputHost *vih = opaque;
+    VirtIOInput *vinput = VIRTIO_INPUT(vih);
+    struct virtio_input_event virtio;
+    struct input_event evdev;
+    int rc;
+
+    for (;;) {
+        rc = read(vih->fd, &evdev, sizeof(evdev));
+        if (rc != sizeof(evdev)) {
+            break;
+        }
+
+        virtio.type  = cpu_to_le16(evdev.type);
+        virtio.code  = cpu_to_le16(evdev.code);
+        virtio.value = cpu_to_le32(evdev.value);
+        virtio_input_send(vinput, &virtio);
+    }
+}
+
+static void virtio_input_bits_config(VirtIOInputHost *vih,
+                                     int type, int count)
+{
+    virtio_input_config bits;
+    int rc, i, size = 0;
+
+    memset(&bits, 0, sizeof(bits));
+    rc = ioctl(vih->fd, EVIOCGBIT(type, count/8), bits.u.bitmap);
+    if (rc < 0) {
+        return;
+    }
+
+    for (i = 0; i < count/8; i++) {
+        if (bits.u.bitmap[i]) {
+            size = i+1;
+        }
+    }
+    if (size == 0) {
+        return;
+    }
+
+    bits.select = VIRTIO_INPUT_CFG_EV_BITS;
+    bits.subsel = type;
+    bits.size   = size;
+    virtio_input_add_config(VIRTIO_INPUT(vih), &bits);
+}
+
+static void virtio_input_host_realize(DeviceState *dev, Error **errp)
+{
+    VirtIOInputHost *vih = VIRTIO_INPUT_HOST(dev);
+    VirtIOInput *vinput = VIRTIO_INPUT(dev);
+    virtio_input_config id;
+    struct input_id ids;
+    int rc, ver;
+
+    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);
+        return;
+    }
+    qemu_set_nonblock(vih->fd);
+
+    rc = ioctl(vih->fd, EVIOCGVERSION, &ver);
+    if (rc < 0) {
+        error_setg(errp, "%s: is not an evdev device", vih->evdev);
+        goto err_close;
+    }
+
+    rc = ioctl(vih->fd, EVIOCGRAB, 1);
+    if (rc < 0) {
+        error_setg_errno(errp, errno, "%s: failed to get exclusive access",
+                         vih->evdev);
+        goto err_close;
+    }
+
+    memset(&id, 0, sizeof(id));
+    ioctl(vih->fd, EVIOCGNAME(sizeof(id.u.string)-1), id.u.string);
+    id.select = VIRTIO_INPUT_CFG_ID_NAME;
+    id.size = strlen(id.u.string);
+    virtio_input_add_config(vinput, &id);
+
+    if (ioctl(vih->fd, EVIOCGID, &ids) == 0) {
+        memset(&id, 0, sizeof(id));
+        id.select = VIRTIO_INPUT_CFG_ID_DEVIDS;
+        id.size = sizeof(struct virtio_input_devids);
+        id.u.ids.bustype = cpu_to_le16(ids.bustype);
+        id.u.ids.vendor  = cpu_to_le16(ids.vendor);
+        id.u.ids.product = cpu_to_le16(ids.product);
+        id.u.ids.version = cpu_to_le16(ids.version);
+        virtio_input_add_config(vinput, &id);
+    }
+
+    virtio_input_bits_config(vih, EV_KEY, KEY_CNT);
+    virtio_input_bits_config(vih, EV_REL, REL_CNT);
+    virtio_input_bits_config(vih, EV_ABS, ABS_CNT);
+    virtio_input_bits_config(vih, EV_MSC, MSC_CNT);
+    virtio_input_bits_config(vih, EV_SW,  SW_CNT);
+
+    qemu_set_fd_handler(vih->fd, virtio_input_host_event, NULL, vih);
+    return;
+
+err_close:
+    close(vih->fd);
+    vih->fd = -1;
+    return;
+}
+
+static void virtio_input_host_unrealize(DeviceState *dev, Error **errp)
+{
+    VirtIOInputHost *vih = VIRTIO_INPUT_HOST(dev);
+
+    if (vih->fd > 0) {
+        qemu_set_fd_handler(vih->fd, NULL, NULL, NULL);
+        close(vih->fd);
+    }
+}
+
+static const VMStateDescription vmstate_virtio_input_host = {
+    .name = "virtio-input-host",
+    .unmigratable = 1,
+};
+
+static Property virtio_input_host_properties[] = {
+    DEFINE_PROP_STRING("evdev", VirtIOInputHost, evdev),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void virtio_input_host_class_init(ObjectClass *klass, void *data)
+{
+    VirtIOInputClass *vic = VIRTIO_INPUT_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->vmsd           = &vmstate_virtio_input_host;
+    dc->props          = virtio_input_host_properties;
+    vic->realize       = virtio_input_host_realize;
+    vic->unrealize     = virtio_input_host_unrealize;
+}
+
+static void virtio_input_host_init(Object *obj)
+{
+    VirtIOInput *vinput = VIRTIO_INPUT(obj);
+
+    virtio_input_init_config(vinput, virtio_input_host_config);
+}
+
+static const TypeInfo virtio_input_host_info = {
+    .name          = TYPE_VIRTIO_INPUT_HOST,
+    .parent        = TYPE_VIRTIO_INPUT,
+    .instance_size = sizeof(VirtIOInputHost),
+    .instance_init = virtio_input_host_init,
+    .class_init    = virtio_input_host_class_init,
+};
+
+/* ----------------------------------------------------------------- */
+
+static void virtio_register_types(void)
+{
+    type_register_static(&virtio_input_host_info);
+}
+
+type_init(virtio_register_types)