[Qemu-devel] [PATCH 2/2] virtio-input: evdev passthrough

[Gerd Hoffmann]

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 <address@hidden>
---
 hw/input/Makefile.objs           |   1 +
 hw/input/virtio-input-host.c     | 182 +++++++++++++++++++++++++++++++++++++++
 hw/virtio/virtio-pci.c           |  30 +++++++
 hw/virtio/virtio-pci.h           |  10 +++
 include/hw/virtio/virtio-input.h |  13 +++
 5 files changed, 236 insertions(+)
 create mode 100644 hw/input/virtio-input-host.c

diff --git a/hw/input/Makefile.objs b/hw/input/Makefile.objs
index 0dae710..624ba7e 100644
--- a/hw/input/Makefile.objs
+++ b/hw/input/Makefile.objs
@@ -11,6 +11,7 @@ common-obj-$(CONFIG_VMMOUSE) += vmmouse.o
 ifeq ($(CONFIG_LINUX),y)
 common-obj-$(CONFIG_VIRTIO) += virtio-input.o
 common-obj-$(CONFIG_VIRTIO) += virtio-input-hid.o
+common-obj-$(CONFIG_VIRTIO) += virtio-input-host.o
 endif
 
 obj-$(CONFIG_MILKYMIST) += milkymist-softusb.o
diff --git a/hw/input/virtio-input-host.c b/hw/input/virtio-input-host.c
new file mode 100644
index 0000000..b16cc4c
--- /dev/null
+++ b/hw/input/virtio-input-host.c
@@ -0,0 +1,182 @@
+/*
+ * 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 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;
+    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)
diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c
index d7cf34c..95ba89c 100644
--- a/hw/virtio/virtio-pci.c
+++ b/hw/virtio/virtio-pci.c
@@ -1906,6 +1906,13 @@ static Property virtio_input_hid_pci_properties[] = {
     DEFINE_PROP_END_OF_LIST(),
 };
 
+static Property virtio_input_host_pci_properties[] = {
+    DEFINE_VIRTIO_INPUT_PROPERTIES(VirtIOInputPCI, vdev.input),
+    DEFINE_PROP_STRING("evdev", VirtIOInputHostPCI, vdev.evdev),
+    DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, 2),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
 static void virtio_input_pci_realize(VirtIOPCIProxy *vpci_dev, Error **errp)
 {
     VirtIOInputPCI *vinput = VIRTIO_INPUT_PCI(vpci_dev);
@@ -1952,6 +1959,13 @@ static void 
virtio_input_hid_mouse_pci_class_init(ObjectClass *klass,
     pcidev_k->class_id = PCI_CLASS_INPUT_MOUSE;
 }
 
+static void virtio_input_host_pci_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->props = virtio_input_host_pci_properties;
+}
+
 static void virtio_keyboard_initfn(Object *obj)
 {
     VirtIOInputHIDPCI *dev = VIRTIO_INPUT_HID_PCI(obj);
@@ -1973,6 +1987,13 @@ static void virtio_tablet_initfn(Object *obj)
     object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
 }
 
+static void virtio_host_initfn(Object *obj)
+{
+    VirtIOInputHostPCI *dev = VIRTIO_INPUT_HOST_PCI(obj);
+    object_initialize(&dev->vdev, sizeof(dev->vdev), TYPE_VIRTIO_INPUT_HOST);
+    object_property_add_child(obj, "virtio-backend", OBJECT(&dev->vdev), NULL);
+}
+
 static const TypeInfo virtio_input_pci_info = {
     .name          = TYPE_VIRTIO_INPUT_PCI,
     .parent        = TYPE_VIRTIO_PCI,
@@ -2012,6 +2033,14 @@ static const TypeInfo virtio_tablet_pci_info = {
     .instance_init = virtio_tablet_initfn,
 };
 
+static const TypeInfo virtio_host_pci_info = {
+    .name          = TYPE_VIRTIO_INPUT_HOST_PCI,
+    .parent        = TYPE_VIRTIO_INPUT_PCI,
+    .instance_size = sizeof(VirtIOInputHostPCI),
+    .instance_init = virtio_host_initfn,
+    .class_init    = virtio_input_host_pci_class_init,
+};
+
 /* virtio-pci-bus */
 
 static void virtio_pci_bus_new(VirtioBusState *bus, size_t bus_size,
@@ -2058,6 +2087,7 @@ static void virtio_pci_register_types(void)
     type_register_static(&virtio_keyboard_pci_info);
     type_register_static(&virtio_mouse_pci_info);
     type_register_static(&virtio_tablet_pci_info);
+    type_register_static(&virtio_host_pci_info);
     type_register_static(&virtio_pci_bus_info);
     type_register_static(&virtio_pci_info);
 #ifdef CONFIG_VIRTFS
diff --git a/hw/virtio/virtio-pci.h b/hw/virtio/virtio-pci.h
index d962125..e7c8f22 100644
--- a/hw/virtio/virtio-pci.h
+++ b/hw/virtio/virtio-pci.h
@@ -42,6 +42,7 @@ typedef struct VHostSCSIPCI VHostSCSIPCI;
 typedef struct VirtIORngPCI VirtIORngPCI;
 typedef struct VirtIOInputPCI VirtIOInputPCI;
 typedef struct VirtIOInputHIDPCI VirtIOInputHIDPCI;
+typedef struct VirtIOInputHostPCI VirtIOInputHostPCI;
 
 /* virtio-pci-bus */
 
@@ -261,6 +262,15 @@ struct VirtIOInputHIDPCI {
     VirtIOInputHID vdev;
 };
 
+#define TYPE_VIRTIO_INPUT_HOST_PCI "virtio-input-host-pci"
+#define VIRTIO_INPUT_HOST_PCI(obj) \
+        OBJECT_CHECK(VirtIOInputHostPCI, (obj), TYPE_VIRTIO_INPUT_HOST_PCI)
+
+struct VirtIOInputHostPCI {
+    VirtIOPCIProxy parent_obj;
+    VirtIOInputHost vdev;
+};
+
 /* Virtio ABI version, if we increment this, we break the guest driver. */
 #define VIRTIO_PCI_ABI_VERSION          0
 
diff --git a/include/hw/virtio/virtio-input.h b/include/hw/virtio/virtio-input.h
index 7b46e62..8c484da 100644
--- a/include/hw/virtio/virtio-input.h
+++ b/include/hw/virtio/virtio-input.h
@@ -50,6 +50,12 @@ typedef struct virtio_input_event virtio_input_event;
 #define VIRTIO_INPUT_HID_GET_PARENT_CLASS(obj) \
         OBJECT_GET_PARENT_CLASS(obj, TYPE_VIRTIO_INPUT_HID)
 
+#define TYPE_VIRTIO_INPUT_HOST   "virtio-input-host-device"
+#define VIRTIO_INPUT_HOST(obj) \
+        OBJECT_CHECK(VirtIOInputHost, (obj), TYPE_VIRTIO_INPUT_HOST)
+#define VIRTIO_INPUT_HOST_GET_PARENT_CLASS(obj) \
+        OBJECT_GET_PARENT_CLASS(obj, TYPE_VIRTIO_INPUT_HOST)
+
 #define DEFINE_VIRTIO_INPUT_PROPERTIES(_state, _field)       \
         DEFINE_PROP_STRING("serial", _state, _field.serial)
 
@@ -57,6 +63,7 @@ typedef struct VirtIOInput VirtIOInput;
 typedef struct VirtIOInputClass VirtIOInputClass;
 typedef struct VirtIOInputConfig VirtIOInputConfig;
 typedef struct VirtIOInputHID VirtIOInputHID;
+typedef struct VirtIOInputHost VirtIOInputHost;
 
 struct virtio_input_conf {
     char *serial;
@@ -99,6 +106,12 @@ struct VirtIOInputHID {
     int                               ledstate;
 };
 
+struct VirtIOInputHost {
+    VirtIOInput                       parent_obj;
+    char                              *evdev;
+    int                               fd;
+};
+
 void virtio_input_send(VirtIOInput *vinput, virtio_input_event *event);
 void virtio_input_init_config(VirtIOInput *vinput,
                               virtio_input_config *config);
-- 
1.8.3.1