[Qemu-devel] [RFC 06/14] contrib: add vhost-user-input

[marcandre.lureau@redhat.com]

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

Add a vhost-user input backend example, based on virtio-input-host
device. It takes an evdev path as argument, and can be associated with a
vhost-user-backend object, ex:

-object vhost-user-backend,id=vuid,cmd="vhost-user-input /dev/input/event0"

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 Makefile                               |   3 +
 Makefile.objs                          |   1 +
 configure                              |   1 +
 contrib/vhost-user-input/Makefile.objs |   1 +
 contrib/vhost-user-input/main.c        | 369 +++++++++++++++++++++++++++++++++
 5 files changed, 375 insertions(+)
 create mode 100644 contrib/vhost-user-input/Makefile.objs
 create mode 100644 contrib/vhost-user-input/main.c

diff --git a/Makefile b/Makefile
index 251217c..ae054de 100644
--- a/Makefile
+++ b/Makefile
@@ -152,6 +152,7 @@ dummy := $(call unnest-vars,, \
                 ivshmem-client-obj-y \
                 ivshmem-server-obj-y \
                 libvhost-user-obj-y \
+                vhost-user-input-obj-y \
                 qga-vss-dll-obj-y \
                 block-obj-y \
                 block-obj-m \
@@ -332,6 +333,8 @@ ivshmem-client$(EXESUF): $(ivshmem-client-obj-y) libqemuutil.a libqemustub.a
 	$(call LINK, $^)
 ivshmem-server$(EXESUF): $(ivshmem-server-obj-y) libqemuutil.a libqemustub.a
 	$(call LINK, $^)
+vhost-user-input$(EXESUF): $(vhost-user-input-obj-y) $(libvhost-user-obj-y) libqemuutil.a libqemustub.a
+	$(call LINK, $^)
 
 clean:
 # avoid old build problems by removing potentially incorrect old files
diff --git a/Makefile.objs b/Makefile.objs
index 5812da7..cdd48ca 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -116,3 +116,4 @@ qga-vss-dll-obj-y = qga/
 ivshmem-client-obj-y = contrib/ivshmem-client/
 ivshmem-server-obj-y = contrib/ivshmem-server/
 libvhost-user-obj-y = contrib/libvhost-user/
+vhost-user-input-obj-y = contrib/vhost-user-input/
diff --git a/configure b/configure
index b5aab72..b02c0f4 100755
--- a/configure
+++ b/configure
@@ -4602,6 +4602,7 @@ if test "$want_tools" = "yes" ; then
   if [ "$linux" = "yes" -o "$bsd" = "yes" -o "$solaris" = "yes" ] ; then
     tools="qemu-nbd\$(EXESUF) $tools"
     tools="ivshmem-client\$(EXESUF) ivshmem-server\$(EXESUF) $tools"
+    tools="vhost-user-input\$(EXESUF) $tools"
   fi
 fi
 if test "$softmmu" = yes ; then
diff --git a/contrib/vhost-user-input/Makefile.objs b/contrib/vhost-user-input/Makefile.objs
new file mode 100644
index 0000000..b1fad90
--- /dev/null
+++ b/contrib/vhost-user-input/Makefile.objs
@@ -0,0 +1 @@
+vhost-user-input-obj-y = main.o
diff --git a/contrib/vhost-user-input/main.c b/contrib/vhost-user-input/main.c
new file mode 100644
index 0000000..31eecb8
--- /dev/null
+++ b/contrib/vhost-user-input/main.c
@@ -0,0 +1,369 @@
+#include <glib.h>
+#include <linux/input.h>
+
+#include "qemu/osdep.h"
+#include "qemu/iov.h"
+#include "qemu/bswap.h"
+#include "contrib/libvhost-user/libvhost-user.h"
+#include "standard-headers/linux/virtio_input.h"
+
+typedef struct virtio_input_event virtio_input_event;
+typedef struct virtio_input_config virtio_input_config;
+
+typedef struct VuInput {
+    VuDev dev;
+    GSource *watches[16];
+    int evdevfd;
+    GArray *config;
+    virtio_input_event *queue;
+    uint32_t qindex, qsize;
+} VuInput;
+
+static void vi_input_send(VuInput *vi, struct virtio_input_event *event)
+{
+    VuDev *dev = &vi->dev;
+    VuVirtq *vq = vu_get_queue(dev, 0);
+    VuVirtqElement *elem;
+    unsigned have, need;
+    int i, len;
+
+    /* queue up events ... */
+    if (vi->qindex == vi->qsize) {
+        vi->qsize++;
+        vi->queue = realloc(vi->queue, vi->qsize *
+                                sizeof(virtio_input_event));
+    }
+    vi->queue[vi->qindex++] = *event;
+
+    /* ... until we see a report sync ... */
+    if (event->type != htole16(EV_SYN) ||
+        event->code != htole16(SYN_REPORT)) {
+        return;
+    }
+
+    /* ... then check available space ... */
+    need = sizeof(virtio_input_event) * vi->qindex;
+    vu_queue_get_avail_bytes(dev, vq, &have, NULL, need, 0);
+    if (have < need) {
+        vi->qindex = 0;
+        g_warning("ENOSPC in vq, dropping events");
+        return;
+    }
+
+    /* ... and finally pass them to the guest */
+    for (i = 0; i < vi->qindex; i++) {
+        elem = vu_queue_pop(dev, vq, sizeof(VuVirtqElement));
+        if (!elem) {
+            /* should not happen, we've checked for space beforehand */
+            g_warning("%s: Huh?  No vq elem available ...\n", __func__);
+            return;
+        }
+        len = iov_from_buf(elem->in_sg, elem->in_num,
+                           0, vi->queue + i, sizeof(virtio_input_event));
+        vu_queue_push(dev, vq, elem, len);
+        g_free(elem);
+    }
+    vu_queue_notify(&vi->dev, vq);
+    vi->qindex = 0;
+}
+
+static void
+vi_evdev_watch(VuDev *dev, int condition, void *data)
+{
+    VuInput *vi = data;
+    int fd = vi->evdevfd;
+
+    g_debug("Got evdev condition %x", condition);
+
+    struct virtio_input_event virtio;
+    struct input_event evdev;
+    int rc;
+
+    for (;;) {
+        rc = read(fd, &evdev, sizeof(evdev));
+        if (rc != sizeof(evdev)) {
+            break;
+        }
+
+        g_debug("input %d %d %d", evdev.type, evdev.code, evdev.value);
+
+        virtio.type  = htole16(evdev.type);
+        virtio.code  = htole16(evdev.code);
+        virtio.value = htole32(evdev.value);
+        vi_input_send(vi, &virtio);
+    }
+}
+
+static void vi_handle_sts(VuDev *dev, int qidx)
+{
+    VuInput *vi = container_of(dev, VuInput, dev);
+    VuVirtq *vq = vu_get_queue(dev, qidx);
+    virtio_input_event event;
+    VuVirtqElement *elem;
+    int len;
+
+    g_debug("%s", __func__);
+
+    for (;;) {
+        elem = vu_queue_pop(dev, vq, sizeof(VuVirtqElement));
+        if (!elem) {
+            break;
+        }
+
+        memset(&event, 0, sizeof(event));
+        len = iov_to_buf(elem->out_sg, elem->out_num,
+                         0, &event, sizeof(event));
+        g_debug("TODO handle status %d %p", len, elem);
+        vu_queue_push(dev, vq, elem, len);
+        g_free(elem);
+    }
+
+    vu_queue_notify(&vi->dev, vq);
+}
+
+static void
+vi_panic(VuDev *dev, const char *msg)
+{
+    g_critical("%s\n", msg);
+    exit(1);
+}
+
+typedef struct Watch {
+    GSource       source;
+    GIOCondition  condition;
+    gpointer      tag;
+    VuDev        *dev;
+    guint         id;
+} Watch;
+
+static GIOCondition
+vu_to_gio_condition(int condition)
+{
+    return (condition & VU_WATCH_IN ? G_IO_IN : 0) |
+           (condition & VU_WATCH_OUT ? G_IO_OUT : 0) |
+           (condition & VU_WATCH_PRI ? G_IO_PRI : 0) |
+           (condition & VU_WATCH_ERR ? G_IO_ERR : 0) |
+           (condition & VU_WATCH_HUP ? G_IO_HUP : 0);
+}
+
+static GIOCondition
+vu_from_gio_condition(int condition)
+{
+    return (condition & G_IO_IN ? VU_WATCH_IN : 0) |
+           (condition & G_IO_OUT ? VU_WATCH_OUT : 0) |
+           (condition & G_IO_PRI ? VU_WATCH_PRI : 0) |
+           (condition & G_IO_ERR ? VU_WATCH_ERR : 0) |
+           (condition & G_IO_HUP ? VU_WATCH_HUP : 0);
+}
+
+static gboolean
+watch_check(GSource *source)
+{
+    Watch *watch = (Watch *)source;
+    GIOCondition poll_condition = g_source_query_unix_fd(source, watch->tag);
+
+    return poll_condition & watch->condition;
+}
+
+static gboolean
+watch_dispatch(GSource *source,
+               GSourceFunc callback,
+               gpointer user_data)
+
+{
+    vu_watch_cb func = (vu_watch_cb)callback;
+    Watch *watch = (Watch *)source;
+    GIOCondition poll_condition = g_source_query_unix_fd(source, watch->tag);
+    int cond = vu_from_gio_condition(poll_condition & watch->condition);
+
+    (*func) (watch->dev, cond, user_data);
+
+    return G_SOURCE_CONTINUE;
+}
+
+static GSourceFuncs watch_funcs = {
+    .check = watch_check,
+    .dispatch = watch_dispatch,
+};
+
+static void
+set_fd_handler(VuDev *dev, int fd, GIOCondition condition,
+               vu_watch_cb cb, void *data)
+{
+    VuInput *vi = container_of(dev, VuInput, dev);
+    Watch *watch;
+    GSource *s;
+
+    g_assert_cmpint(fd, <, G_N_ELEMENTS(vi->watches));
+
+    s = vi->watches[fd];
+    if (cb) {
+        if (!s) {
+            s = g_source_new(&watch_funcs, sizeof(Watch));
+            watch = (Watch *)s;
+            watch->dev = dev;
+            watch->condition = condition;
+            watch->tag =
+                g_source_add_unix_fd(s, fd, condition);
+            watch->id = g_source_attach(s, NULL);
+            vi->watches[fd] = s;
+        } else {
+            watch = (Watch *)s;
+            g_source_modify_unix_fd(s, watch->tag, condition);
+        }
+
+        g_source_set_callback(s, (GSourceFunc)cb, data, NULL);
+    } else if (s) {
+        watch = (Watch *)s;
+        g_source_remove_unix_fd(s, watch->tag);
+        g_source_unref(s);
+        g_source_remove(watch->id);
+        vi->watches[fd] = NULL;
+    }
+}
+
+static void
+vi_add_watch(VuDev *dev, int fd, int condition,
+             vu_watch_cb cb, void *data)
+{
+    set_fd_handler(dev, fd, vu_to_gio_condition(condition), cb, data);
+}
+
+static void
+vi_remove_watch(VuDev *dev, int fd)
+{
+    set_fd_handler(dev, fd, 0, NULL, NULL);
+}
+
+static void
+vi_queue_set_started(VuDev *dev, int qidx, bool started)
+{
+    VuInput *vi = container_of(dev, VuInput, dev);
+    VuVirtq *vq = vu_get_queue(dev, qidx);
+
+    g_debug("queue started %d:%d", qidx, started);
+
+    if (qidx == 0) {
+        set_fd_handler(dev, vi->evdevfd, G_IO_IN,
+                       started ? vi_evdev_watch : NULL, vi);
+    } else {
+        vu_set_queue_handler(dev, vq, started ? vi_handle_sts : NULL);
+    }
+}
+
+static void
+vi_vhost_watch(VuDev *dev, int condition, void *data)
+{
+    vu_dispatch(dev);
+}
+
+static int
+vi_process_msg(VuDev *dev, VhostUserMsg *vmsg, int *do_reply)
+{
+    VuInput *vi = container_of(dev, VuInput, dev);
+
+    switch (vmsg->request) {
+    case VHOST_USER_INPUT_GET_CONFIG:
+        vmsg->size = vi->config->len * sizeof(virtio_input_config);
+        vmsg->data = g_memdup(vi->config->data, vmsg->size);
+        *do_reply = true;
+        return 1;
+    default:
+        return 0;
+    }
+}
+
+static const VuDevIface vuiface = {
+    .queue_set_started = vi_queue_set_started,
+    .process_msg = vi_process_msg,
+};
+
+static void
+vi_bits_config(VuInput *vi, int type, int count)
+{
+    virtio_input_config bits;
+    int rc, i, size = 0;
+
+    memset(&bits, 0, sizeof(bits));
+    rc = ioctl(vi->evdevfd, 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;
+    g_array_append_val(vi->config, bits);
+}
+
+int
+main(int argc, char *argv[])
+{
+    GMainLoop *loop = NULL;
+    VuInput vi = { 0, };
+    int rc, ver;
+    virtio_input_config id;
+    struct input_id ids;
+
+    if (argc != 2) {
+        g_error("evdev path argument required");
+    }
+
+    vi.evdevfd = open(argv[1], O_RDWR);
+    if (vi.evdevfd < 0) {
+        g_error("Failed to open evdev: %s", g_strerror(errno));
+    }
+
+    rc = ioctl(vi.evdevfd, EVIOCGVERSION, &ver);
+    if (rc < 0) {
+        g_error("%s: is not an evdev device", argv[1]);
+    }
+
+    rc = ioctl(vi.evdevfd, EVIOCGRAB, 1);
+    if (rc < 0) {
+        g_error("Failed to grab device");
+    }
+
+    vi.config = g_array_new(false, false, sizeof(virtio_input_config));
+    memset(&id, 0, sizeof(id));
+    ioctl(vi.evdevfd, EVIOCGNAME(sizeof(id.u.string) - 1), id.u.string);
+    id.select = VIRTIO_INPUT_CFG_ID_NAME;
+    id.size = strlen(id.u.string);
+    g_array_append_val(vi.config, id);
+
+    if (ioctl(vi.evdevfd, 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);
+        g_array_append_val(vi.config, id);
+    }
+
+    vi_bits_config(&vi, EV_KEY, KEY_CNT);
+    vi_bits_config(&vi, EV_REL, REL_CNT);
+    vi_bits_config(&vi, EV_ABS, ABS_CNT);
+    vi_bits_config(&vi, EV_MSC, MSC_CNT);
+    vi_bits_config(&vi, EV_SW,  SW_CNT);
+    g_debug("config length: %u", vi.config->len);
+
+    vu_init(&vi.dev, 3, vi_panic, vi_add_watch, vi_remove_watch, &vuiface);
+    set_fd_handler(&vi.dev, 3, G_IO_IN | G_IO_HUP, vi_vhost_watch, NULL);
+
+    loop = g_main_loop_new(NULL, FALSE);
+    g_main_loop_run(loop);
+    g_main_loop_unref(loop);
+
+    return 0;
+}
-- 
2.7.4