[Qemu-devel] [PULL 2/5] input: linux evdev support

[Gerd Hoffmann]

This patch adds support for reading input events directly from linux
evdev devices and forward them to the guest.  Unlike virtio-input-host
which simply passes on all events to the guest without looking at them
this will interpret the events and feed them into the qemu input
subsystem.

Therefore this is limited to what the qemu input subsystem and the
emulated input devices are able to handle.  Also there is no support for
absolute coordinates (tablet/touchscreen).  So we are talking here about
basic mouse and keyboard support.

The advantage is that it'll work without virtio-input drivers in the
guest, the events are delivered to the usual ps/2 or usb input devices
(depending on what the machine happens to have).  And for keyboards
qemu is able to switch the keyboard between guest and host on hotkey.
The hotkey is hard-coded for now (both control keys), initialy the
guest owns the keyboard.

Probably most useful when assigning vga devices with vfio and using a
physical monitor instead of vnc/spice/gtk as guest display.

Usage:  Add '-input-linux /dev/input/event<nr>' to the qemu command
line.  Note that udev has rules which populate /dev/input/by-{id,path}
with static names, which might be more convinient to use.

Signed-off-by: Gerd Hoffmann <address@hidden>
Message-id: address@hidden
---
 include/ui/input.h |   2 +
 qemu-options.hx    |   9 ++
 ui/Makefile.objs   |   1 +
 ui/input-linux.c   | 357 +++++++++++++++++++++++++++++++++++++++++++++++++++++
 vl.c               |  11 ++
 5 files changed, 380 insertions(+)
 create mode 100644 ui/input-linux.c

diff --git a/include/ui/input.h b/include/ui/input.h
index d06a12d..102d8a3 100644
--- a/include/ui/input.h
+++ b/include/ui/input.h
@@ -65,4 +65,6 @@ void qemu_input_check_mode_change(void);
 void qemu_add_mouse_mode_change_notifier(Notifier *notify);
 void qemu_remove_mouse_mode_change_notifier(Notifier *notify);
 
+int input_linux_init(void *opaque, QemuOpts *opts, Error **errp);
+
 #endif /* INPUT_H */
diff --git a/qemu-options.hx b/qemu-options.hx
index 144e6a9..bda92d2 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1226,6 +1226,15 @@ STEXI
 Set the initial graphical resolution and depth (PPC, SPARC only).
 ETEXI
 
+DEF("input-linux", 1, QEMU_OPTION_input_linux,
+    "-input-linux <evdev>\n"
+    "                Use input device.\n", QEMU_ARCH_ALL)
+STEXI
address@hidden -input-linux @var{dev}
address@hidden -input-linux
+Use input device.
+ETEXI
+
 DEF("vnc", HAS_ARG, QEMU_OPTION_vnc ,
     "-vnc display    start a VNC server on display\n", QEMU_ARCH_ALL)
 STEXI
diff --git a/ui/Makefile.objs b/ui/Makefile.objs
index 728393c..dc936f1 100644
--- a/ui/Makefile.objs
+++ b/ui/Makefile.objs
@@ -9,6 +9,7 @@ vnc-obj-y += vnc-jobs.o
 
 common-obj-y += keymaps.o console.o cursor.o qemu-pixman.o
 common-obj-y += input.o input-keymap.o input-legacy.o
+common-obj-$(CONFIG_LINUX) += input-linux.o
 common-obj-$(CONFIG_SPICE) += spice-core.o spice-input.o spice-display.o
 common-obj-$(CONFIG_SDL) += sdl.mo x_keymap.o
 common-obj-$(CONFIG_COCOA) += cocoa.o
diff --git a/ui/input-linux.c b/ui/input-linux.c
new file mode 100644
index 0000000..5374a2e
--- /dev/null
+++ b/ui/input-linux.c
@@ -0,0 +1,357 @@
+/*
+ * 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/osdep.h"
+#include "qemu-common.h"
+#include "qemu/config-file.h"
+#include "qemu/sockets.h"
+#include "sysemu/sysemu.h"
+#include "ui/input.h"
+
+#include <sys/ioctl.h>
+#include "standard-headers/linux/input.h"
+
+static int linux_to_qcode[KEY_CNT] = {
+    [KEY_ESC]            = Q_KEY_CODE_ESC,
+    [KEY_1]              = Q_KEY_CODE_1,
+    [KEY_2]              = Q_KEY_CODE_2,
+    [KEY_3]              = Q_KEY_CODE_3,
+    [KEY_4]              = Q_KEY_CODE_4,
+    [KEY_5]              = Q_KEY_CODE_5,
+    [KEY_6]              = Q_KEY_CODE_6,
+    [KEY_7]              = Q_KEY_CODE_7,
+    [KEY_8]              = Q_KEY_CODE_8,
+    [KEY_9]              = Q_KEY_CODE_9,
+    [KEY_0]              = Q_KEY_CODE_0,
+    [KEY_MINUS]          = Q_KEY_CODE_MINUS,
+    [KEY_EQUAL]          = Q_KEY_CODE_EQUAL,
+    [KEY_BACKSPACE]      = Q_KEY_CODE_BACKSPACE,
+    [KEY_TAB]            = Q_KEY_CODE_TAB,
+    [KEY_Q]              = Q_KEY_CODE_Q,
+    [KEY_W]              = Q_KEY_CODE_W,
+    [KEY_E]              = Q_KEY_CODE_E,
+    [KEY_R]              = Q_KEY_CODE_R,
+    [KEY_T]              = Q_KEY_CODE_T,
+    [KEY_Y]              = Q_KEY_CODE_Y,
+    [KEY_U]              = Q_KEY_CODE_U,
+    [KEY_I]              = Q_KEY_CODE_I,
+    [KEY_O]              = Q_KEY_CODE_O,
+    [KEY_P]              = Q_KEY_CODE_P,
+    [KEY_LEFTBRACE]      = Q_KEY_CODE_BRACKET_LEFT,
+    [KEY_RIGHTBRACE]     = Q_KEY_CODE_BRACKET_RIGHT,
+    [KEY_ENTER]          = Q_KEY_CODE_RET,
+    [KEY_LEFTCTRL]       = Q_KEY_CODE_CTRL,
+    [KEY_A]              = Q_KEY_CODE_A,
+    [KEY_S]              = Q_KEY_CODE_S,
+    [KEY_D]              = Q_KEY_CODE_D,
+    [KEY_F]              = Q_KEY_CODE_F,
+    [KEY_G]              = Q_KEY_CODE_G,
+    [KEY_H]              = Q_KEY_CODE_H,
+    [KEY_J]              = Q_KEY_CODE_J,
+    [KEY_K]              = Q_KEY_CODE_K,
+    [KEY_L]              = Q_KEY_CODE_L,
+    [KEY_SEMICOLON]      = Q_KEY_CODE_SEMICOLON,
+    [KEY_APOSTROPHE]     = Q_KEY_CODE_APOSTROPHE,
+    [KEY_GRAVE]          = Q_KEY_CODE_GRAVE_ACCENT,
+    [KEY_LEFTSHIFT]      = Q_KEY_CODE_SHIFT,
+    [KEY_BACKSLASH]      = Q_KEY_CODE_BACKSLASH,
+    [KEY_102ND]          = Q_KEY_CODE_LESS,
+    [KEY_Z]              = Q_KEY_CODE_Z,
+    [KEY_X]              = Q_KEY_CODE_X,
+    [KEY_C]              = Q_KEY_CODE_C,
+    [KEY_V]              = Q_KEY_CODE_V,
+    [KEY_B]              = Q_KEY_CODE_B,
+    [KEY_N]              = Q_KEY_CODE_N,
+    [KEY_M]              = Q_KEY_CODE_M,
+    [KEY_COMMA]          = Q_KEY_CODE_COMMA,
+    [KEY_DOT]            = Q_KEY_CODE_DOT,
+    [KEY_SLASH]          = Q_KEY_CODE_SLASH,
+    [KEY_RIGHTSHIFT]     = Q_KEY_CODE_SHIFT_R,
+    [KEY_LEFTALT]        = Q_KEY_CODE_ALT,
+    [KEY_SPACE]          = Q_KEY_CODE_SPC,
+    [KEY_CAPSLOCK]       = Q_KEY_CODE_CAPS_LOCK,
+    [KEY_F1]             = Q_KEY_CODE_F1,
+    [KEY_F2]             = Q_KEY_CODE_F2,
+    [KEY_F3]             = Q_KEY_CODE_F3,
+    [KEY_F4]             = Q_KEY_CODE_F4,
+    [KEY_F5]             = Q_KEY_CODE_F5,
+    [KEY_F6]             = Q_KEY_CODE_F6,
+    [KEY_F7]             = Q_KEY_CODE_F7,
+    [KEY_F8]             = Q_KEY_CODE_F8,
+    [KEY_F9]             = Q_KEY_CODE_F9,
+    [KEY_F10]            = Q_KEY_CODE_F10,
+    [KEY_NUMLOCK]        = Q_KEY_CODE_NUM_LOCK,
+    [KEY_SCROLLLOCK]     = Q_KEY_CODE_SCROLL_LOCK,
+    [KEY_KP0]            = Q_KEY_CODE_KP_0,
+    [KEY_KP1]            = Q_KEY_CODE_KP_1,
+    [KEY_KP2]            = Q_KEY_CODE_KP_2,
+    [KEY_KP3]            = Q_KEY_CODE_KP_3,
+    [KEY_KP4]            = Q_KEY_CODE_KP_4,
+    [KEY_KP5]            = Q_KEY_CODE_KP_5,
+    [KEY_KP6]            = Q_KEY_CODE_KP_6,
+    [KEY_KP7]            = Q_KEY_CODE_KP_7,
+    [KEY_KP8]            = Q_KEY_CODE_KP_8,
+    [KEY_KP9]            = Q_KEY_CODE_KP_9,
+    [KEY_KPMINUS]        = Q_KEY_CODE_KP_SUBTRACT,
+    [KEY_KPPLUS]         = Q_KEY_CODE_KP_ADD,
+    [KEY_KPDOT]          = Q_KEY_CODE_KP_DECIMAL,
+    [KEY_KPENTER]        = Q_KEY_CODE_KP_ENTER,
+    [KEY_KPSLASH]        = Q_KEY_CODE_KP_DIVIDE,
+    [KEY_KPASTERISK]     = Q_KEY_CODE_KP_MULTIPLY,
+    [KEY_F11]            = Q_KEY_CODE_F11,
+    [KEY_F12]            = Q_KEY_CODE_F12,
+    [KEY_RIGHTCTRL]      = Q_KEY_CODE_CTRL_R,
+    [KEY_SYSRQ]          = Q_KEY_CODE_SYSRQ,
+    [KEY_RIGHTALT]       = Q_KEY_CODE_ALT_R,
+    [KEY_HOME]           = Q_KEY_CODE_HOME,
+    [KEY_UP]             = Q_KEY_CODE_UP,
+    [KEY_PAGEUP]         = Q_KEY_CODE_PGUP,
+    [KEY_LEFT]           = Q_KEY_CODE_LEFT,
+    [KEY_RIGHT]          = Q_KEY_CODE_RIGHT,
+    [KEY_END]            = Q_KEY_CODE_END,
+    [KEY_DOWN]           = Q_KEY_CODE_DOWN,
+    [KEY_PAGEDOWN]       = Q_KEY_CODE_PGDN,
+    [KEY_INSERT]         = Q_KEY_CODE_INSERT,
+    [KEY_DELETE]         = Q_KEY_CODE_DELETE,
+    [KEY_LEFTMETA]       = Q_KEY_CODE_META_L,
+    [KEY_RIGHTMETA]      = Q_KEY_CODE_META_R,
+    [KEY_MENU]           = Q_KEY_CODE_MENU,
+};
+
+static int qemu_input_linux_to_qcode(unsigned int lnx)
+{
+    assert(lnx < KEY_CNT);
+    return linux_to_qcode[lnx];
+}
+
+typedef struct InputLinux InputLinux;
+
+struct InputLinux {
+    const char  *evdev;
+    int         fd;
+    bool        grab_request;
+    bool        grab_active;
+    bool        keydown[KEY_CNT];
+    int         keycount;
+    int         wheel;
+};
+
+static void input_linux_toggle_grab(InputLinux *il)
+{
+    intptr_t request = !il->grab_active;
+    int rc;
+
+    rc = ioctl(il->fd, EVIOCGRAB, request);
+    if (rc < 0) {
+        return;
+    }
+    il->grab_active = !il->grab_active;
+}
+
+static void input_linux_event_keyboard(void *opaque)
+{
+    InputLinux *il = opaque;
+    struct input_event event;
+    int rc;
+
+    for (;;) {
+        rc = read(il->fd, &event, sizeof(event));
+        if (rc != sizeof(event)) {
+            if (rc < 0 && errno != EAGAIN) {
+                fprintf(stderr, "%s: read: %s\n", __func__, strerror(errno));
+                qemu_set_fd_handler(il->fd, NULL, NULL, NULL);
+                close(il->fd);
+            }
+            break;
+        }
+
+        switch (event.type) {
+        case EV_KEY:
+            if (event.value > 1) {
+                /*
+                 * ignore autorepeat + unknown key events
+                 * 0 == up, 1 == down, 2 == autorepeat, other == undefined
+                 */
+                continue;
+            }
+            /* keep track of key state */
+            if (!il->keydown[event.code] && event.value) {
+                il->keydown[event.code] = true;
+                il->keycount++;
+            }
+            if (il->keydown[event.code] && !event.value) {
+                il->keydown[event.code] = false;
+                il->keycount--;
+            }
+
+            /* send event to guest when grab is active */
+            if (il->grab_active) {
+                int qcode = qemu_input_linux_to_qcode(event.code);
+                qemu_input_event_send_key_qcode(NULL, qcode, event.value);
+            }
+
+            /* hotkey -> record switch request ... */
+            if (il->keydown[KEY_LEFTCTRL] &&
+                il->keydown[KEY_RIGHTCTRL]) {
+                il->grab_request = true;
+            }
+
+            /*
+             * ... and do the switch when all keys are lifted, so we
+             * confuse neither guest nor host with keys which seem to
+             * be stuck due to missing key-up events.
+             */
+            if (il->grab_request && !il->keycount) {
+                il->grab_request = false;
+                input_linux_toggle_grab(il);
+            }
+            break;
+        }
+    }
+}
+
+static void input_linux_event_mouse_button(int button)
+{
+    qemu_input_queue_btn(NULL, button, true);
+    qemu_input_event_sync();
+    qemu_input_queue_btn(NULL, button, false);
+    qemu_input_event_sync();
+}
+
+static void input_linux_event_mouse(void *opaque)
+{
+    InputLinux *il = opaque;
+    struct input_event event;
+    int rc;
+
+    for (;;) {
+        rc = read(il->fd, &event, sizeof(event));
+        if (rc != sizeof(event)) {
+            if (rc < 0 && errno != EAGAIN) {
+                fprintf(stderr, "%s: read: %s\n", __func__, strerror(errno));
+                qemu_set_fd_handler(il->fd, NULL, NULL, NULL);
+                close(il->fd);
+            }
+            break;
+        }
+
+        switch (event.type) {
+        case EV_KEY:
+            switch (event.code) {
+            case BTN_LEFT:
+                qemu_input_queue_btn(NULL, INPUT_BUTTON_LEFT, event.value);
+                break;
+            case BTN_RIGHT:
+                qemu_input_queue_btn(NULL, INPUT_BUTTON_RIGHT, event.value);
+                break;
+            case BTN_MIDDLE:
+                qemu_input_queue_btn(NULL, INPUT_BUTTON_MIDDLE, event.value);
+                break;
+            case BTN_GEAR_UP:
+                qemu_input_queue_btn(NULL, INPUT_BUTTON_WHEEL_UP, event.value);
+                break;
+            case BTN_GEAR_DOWN:
+                qemu_input_queue_btn(NULL, INPUT_BUTTON_WHEEL_DOWN,
+                                     event.value);
+                break;
+            };
+            break;
+        case EV_REL:
+            switch (event.code) {
+            case REL_X:
+                qemu_input_queue_rel(NULL, INPUT_AXIS_X, event.value);
+                break;
+            case REL_Y:
+                qemu_input_queue_rel(NULL, INPUT_AXIS_Y, event.value);
+                break;
+            case REL_WHEEL:
+                il->wheel = event.value;
+                break;
+            }
+            break;
+        case EV_SYN:
+            qemu_input_event_sync();
+            if (il->wheel != 0) {
+                input_linux_event_mouse_button((il->wheel > 0)
+                                               ? INPUT_BUTTON_WHEEL_UP
+                                               : INPUT_BUTTON_WHEEL_DOWN);
+                il->wheel = 0;
+            }
+            break;
+        }
+    }
+}
+
+int input_linux_init(void *opaque, QemuOpts *opts, Error **errp)
+{
+    InputLinux *il = g_new0(InputLinux, 1);
+    uint32_t evtmap;
+    int rc, ver;
+
+    il->evdev = qemu_opt_get(opts, "evdev");
+    if (!il->evdev) {
+        error_setg(errp, "no input device specified");
+        goto err_free;
+    }
+
+    il->fd = open(il->evdev, O_RDWR);
+    if (il->fd < 0)  {
+        error_setg_file_open(errp, errno, il->evdev);
+        goto err_free;
+    }
+    qemu_set_nonblock(il->fd);
+
+    rc = ioctl(il->fd, EVIOCGVERSION, &ver);
+    if (rc < 0) {
+        error_setg(errp, "%s: is not an evdev device", il->evdev);
+        goto err_close;
+    }
+
+    rc = ioctl(il->fd, EVIOCGBIT(0, sizeof(evtmap)), &evtmap);
+
+    if (evtmap & (1 << EV_REL)) {
+        /* has relative axis -> assume mouse */
+        qemu_set_fd_handler(il->fd, input_linux_event_mouse, NULL, il);
+    } else if (evtmap & (1 << EV_ABS)) {
+        /* has absolute axis -> not supported */
+        error_setg(errp, "tablet/touchscreen not supported");
+        goto err_close;
+    } else if (evtmap & (1 << EV_KEY)) {
+        /* has keys/buttons (and no axis) -> assume keyboard */
+        qemu_set_fd_handler(il->fd, input_linux_event_keyboard, NULL, il);
+    } else {
+        /* Huh? What is this? */
+        error_setg(errp, "unknown kind of input device");
+        goto err_close;
+    }
+    input_linux_toggle_grab(il);
+    return 0;
+
+err_close:
+    close(il->fd);
+err_free:
+    g_free(il);
+    return -1;
+}
+
+static QemuOptsList qemu_input_linux_opts = {
+    .name = "input-linux",
+    .head = QTAILQ_HEAD_INITIALIZER(qemu_input_linux_opts.head),
+    .implied_opt_name = "evdev",
+    .desc = {
+        {
+            .name = "evdev",
+            .type = QEMU_OPT_STRING,
+        },
+        { /* end of list */ }
+    },
+};
+
+static void input_linux_register_config(void)
+{
+    qemu_add_opts(&qemu_input_linux_opts);
+}
+machine_init(input_linux_register_config);
diff --git a/vl.c b/vl.c
index adeddd9..7a28982 100644
--- a/vl.c
+++ b/vl.c
@@ -72,6 +72,7 @@ int main(int argc, char **argv)
 #include "net/slirp.h"
 #include "monitor/monitor.h"
 #include "ui/console.h"
+#include "ui/input.h"
 #include "sysemu/sysemu.h"
 #include "sysemu/numa.h"
 #include "exec/gdbstub.h"
@@ -3728,6 +3729,12 @@ int main(int argc, char **argv, char **envp)
 #endif
                 break;
             }
+            case QEMU_OPTION_input_linux:
+                if (!qemu_opts_parse_noisily(qemu_find_opts("input-linux"),
+                                             optarg, true)) {
+                    exit(1);
+                }
+                break;
             case QEMU_OPTION_no_acpi:
                 acpi_enabled = 0;
                 break;
@@ -4591,6 +4598,10 @@ int main(int argc, char **argv, char **envp)
         qemu_spice_display_init();
     }
 #endif
+#ifdef CONFIG_LINUX
+    qemu_opts_foreach(qemu_find_opts("input-linux"),
+                      input_linux_init, NULL, &error_fatal);
+#endif
 
     if (foreach_device_config(DEV_GDB, gdbserver_start) < 0) {
         exit(1);
-- 
1.8.3.1