[PATCH 0/6] virtio-console: notify about the terminal size

[PATCH 0/6] virtio-console: notify about the terminal size

[Szymon Lukasz]

The goal of this series is to have a nice terminal into a Linux guest
without having to set up networking and using, e.g. ssh.

The virtio spec allows a virtio-console device to notify the guest about
terminal resizes in the host. Linux Kernel implements the driver part of
the spec. This series implement the device part in QEMU.

In this series resize notifications are only supported for the stdio
backend but I think it should be easy to add support for the vc backend.
Support for tty/serial backends is complicated by the fact that there is
no clean way to detect resizes of the underlying terminal.

Also there is a problem with the virtio spec and Linux Kernel
implementation, the order of fields in virtio_console_resize struct
differs between the kernel and the spec. I do not know if there is any
implementation of the virtio-console driver that handles resize messages
and uses a different order than Linux.



Szymon Lukasz (6):
  main-loop: change the handling of SIGWINCH
  chardev: add support for retrieving the terminal size
  chardev: add support for notifying about terminal resizes
  char-stdio: add support for the terminal size
  virtio-serial-bus: add terminal resize messages
  virtio-console: notify the guest about terminal resizes

 backends/cryptodev-vhost-user.c   |  1 +
 chardev/char-fe.c                 | 11 ++++++
 chardev/char-mux.c                |  7 ++++
 chardev/char-stdio.c              | 34 ++++++++++++++++
 chardev/char.c                    |  1 +
 hw/block/vhost-user-blk.c         |  1 +
 hw/char/terminal3270.c            |  1 +
 hw/char/trace-events              |  1 +
 hw/char/virtio-console.c          | 65 +++++++++++++++++++++++++++++--
 hw/char/virtio-serial-bus.c       | 41 ++++++++++++++++++-
 hw/ipmi/ipmi_bmc_extern.c         |  1 +
 hw/usb/ccid-card-passthru.c       |  1 +
 hw/usb/dev-serial.c               |  1 +
 hw/usb/redirect.c                 |  1 +
 include/chardev/char-fe.h         | 11 ++++++
 include/chardev/char.h            |  2 +
 include/hw/virtio/virtio-serial.h |  5 +++
 include/qemu/main-loop.h          |  4 ++
 monitor/hmp.c                     |  1 +
 monitor/qmp.c                     |  1 +
 net/vhost-user.c                  |  1 +
 ui/curses.c                       | 11 +++---
 util/main-loop.c                  | 21 ++++++++++
 23 files changed, 213 insertions(+), 11 deletions(-)

-- 
2.27.0

[PATCH 1/6] main-loop: change the handling of SIGWINCH

[Szymon Lukasz]

Block SIGWINCH, so it is delivered only via signalfd.
Install a handler that uses NotifierList to tell
interested parties about SIGWINCH delivery.

Signed-off-by: Szymon Lukasz <noh4hss@gmail.com>
---
 include/qemu/main-loop.h |  4 ++++
 ui/curses.c              | 11 ++++++-----
 util/main-loop.c         | 21 +++++++++++++++++++++
 3 files changed, 31 insertions(+), 5 deletions(-)

diff --git a/include/qemu/main-loop.h b/include/qemu/main-loop.h
index a6d20b0719..f27dba1fd8 100644
--- a/include/qemu/main-loop.h
+++ b/include/qemu/main-loop.h
@@ -325,4 +325,8 @@ typedef struct MainLoopPoll {
 void main_loop_poll_add_notifier(Notifier *notify);
 void main_loop_poll_remove_notifier(Notifier *notify);
 
+#ifndef _WIN32
+void sigwinch_add_notifier(Notifier *n);
+#endif
+
 #endif
diff --git a/ui/curses.c b/ui/curses.c
index a59b23a9cf..e5895d506f 100644
--- a/ui/curses.c
+++ b/ui/curses.c
@@ -34,6 +34,7 @@
 #include <iconv.h>
 
 #include "qapi/error.h"
+#include "qemu/main-loop.h"
 #include "qemu/module.h"
 #include "ui/console.h"
 #include "ui/input.h"
@@ -146,7 +147,7 @@ static void curses_resize(DisplayChangeListener *dcl,
 }
 
 #if !defined(_WIN32) && defined(SIGWINCH) && defined(KEY_RESIZE)
-static volatile sig_atomic_t got_sigwinch;
+static bool got_sigwinch;
 static void curses_winch_check(void)
 {
     struct winsize {
@@ -169,17 +170,17 @@ static void curses_winch_check(void)
     invalidate = 1;
 }
 
-static void curses_winch_handler(int signum)
+static void curses_winch_handler(Notifier *n, void *data)
 {
     got_sigwinch = true;
 }
 
 static void curses_winch_init(void)
 {
-    struct sigaction old, winch = {
-        .sa_handler  = curses_winch_handler,
+    static Notifier n = {
+        .notify = curses_winch_handler
     };
-    sigaction(SIGWINCH, &winch, &old);
+    sigwinch_add_notifier(&n);
 }
 #else
 static void curses_winch_check(void) {}
diff --git a/util/main-loop.c b/util/main-loop.c
index eda63fe4e0..0f5c8f3af1 100644
--- a/util/main-loop.c
+++ b/util/main-loop.c
@@ -90,6 +90,7 @@ static int qemu_signal_init(Error **errp)
     sigaddset(&set, SIGIO);
     sigaddset(&set, SIGALRM);
     sigaddset(&set, SIGBUS);
+    sigaddset(&set, SIGWINCH);
     /* SIGINT cannot be handled via signalfd, so that ^C can be used
      * to interrupt QEMU when it is being run under gdb.  SIGHUP and
      * SIGTERM are also handled asynchronously, even though it is not
@@ -111,6 +112,26 @@ static int qemu_signal_init(Error **errp)
     return 0;
 }
 
+static NotifierList sigwinch_notifiers =
+    NOTIFIER_LIST_INITIALIZER(sigwinch_notifiers);
+
+static void sigwinch_handler(int signum)
+{
+    notifier_list_notify(&sigwinch_notifiers, NULL);
+}
+
+void sigwinch_add_notifier(Notifier *n)
+{
+    if (notifier_list_empty(&sigwinch_notifiers)) {
+        struct sigaction action = {
+            .sa_handler = sigwinch_handler,
+        };
+        sigaction(SIGWINCH, &action, NULL);
+    }
+
+    notifier_list_add(&sigwinch_notifiers, n);
+}
+
 #else /* _WIN32 */
 
 static int qemu_signal_init(Error **errp)
-- 
2.27.0

[PATCH 2/6] chardev: add support for retrieving the terminal size

[Szymon Lukasz]

Extend the class of chardevs with a new function - chr_get_winsize.
A chardev backend should implement if it is able to get the size of
the connected terminal and can detect changes in the terminal size,
i.e. if the backend cannot detect resizes it must not implement this
(e.g. if we have a tty backend connected to some (pseudo)terminal
there is no clean way to detect resizes since SIGWINCH is sent only
for the controlling terminal).

Signed-off-by: Szymon Lukasz <noh4hss@gmail.com>
---
 chardev/char-fe.c         | 11 +++++++++++
 chardev/char-mux.c        |  7 +++++++
 include/chardev/char-fe.h | 11 +++++++++++
 include/chardev/char.h    |  1 +
 4 files changed, 30 insertions(+)

diff --git a/chardev/char-fe.c b/chardev/char-fe.c
index f3530a90e6..802d3096cd 100644
--- a/chardev/char-fe.c
+++ b/chardev/char-fe.c
@@ -336,6 +336,17 @@ void qemu_chr_fe_set_echo(CharBackend *be, bool echo)
     }
 }
 
+int qemu_chr_fe_get_winsize(CharBackend *be, uint16_t *cols, uint16_t *rows)
+{
+    Chardev *chr = be->chr;
+
+    if (chr && CHARDEV_GET_CLASS(chr)->chr_get_winsize) {
+        return CHARDEV_GET_CLASS(chr)->chr_get_winsize(chr, cols, rows);
+    }
+
+    return -1;
+}
+
 void qemu_chr_fe_set_open(CharBackend *be, int fe_open)
 {
     Chardev *chr = be->chr;
diff --git a/chardev/char-mux.c b/chardev/char-mux.c
index 46c44af67c..368ce2334e 100644
--- a/chardev/char-mux.c
+++ b/chardev/char-mux.c
@@ -293,6 +293,12 @@ static void mux_chr_update_read_handlers(Chardev *chr)
                                   chr->gcontext, true, false);
 }
 
+static int mux_chr_get_winsize(Chardev *chr, uint16_t *cols, uint16_t *rows)
+{
+    MuxChardev *d = MUX_CHARDEV(chr);
+    return qemu_chr_fe_get_winsize(&d->chr, cols, rows);
+}
+
 void mux_set_focus(Chardev *chr, int focus)
 {
     MuxChardev *d = MUX_CHARDEV(chr);
@@ -385,6 +391,7 @@ static void char_mux_class_init(ObjectClass *oc, void *data)
     cc->chr_be_event = mux_chr_be_event;
     cc->chr_machine_done = open_muxes;
     cc->chr_update_read_handler = mux_chr_update_read_handlers;
+    cc->chr_get_winsize = mux_chr_get_winsize;
 }
 
 static const TypeInfo char_mux_type_info = {
diff --git a/include/chardev/char-fe.h b/include/chardev/char-fe.h
index a553843364..b7943df93a 100644
--- a/include/chardev/char-fe.h
+++ b/include/chardev/char-fe.h
@@ -154,6 +154,17 @@ int qemu_chr_fe_wait_connected(CharBackend *be, Error **errp);
  */
 void qemu_chr_fe_set_echo(CharBackend *be, bool echo);
 
+/**
+ * qemu_chr_fe_get_winsize:
+ * @cols: the address for storing columns
+ * @rows: the address for storing rows
+ *
+ * Get the terminal size of the backend.
+ *
+ * Returns: 0 on success and < 0 on error
+ */
+int qemu_chr_fe_get_winsize(CharBackend *be, uint16_t *cols, uint16_t *rows);
+
 /**
  * qemu_chr_fe_set_open:
  *
diff --git a/include/chardev/char.h b/include/chardev/char.h
index 00589a6025..fb20707917 100644
--- a/include/chardev/char.h
+++ b/include/chardev/char.h
@@ -276,6 +276,7 @@ typedef struct ChardevClass {
     void (*chr_be_event)(Chardev *s, QEMUChrEvent event);
     /* Return 0 if succeeded, 1 if failed */
     int (*chr_machine_done)(Chardev *chr);
+    int (*chr_get_winsize)(Chardev *chr, uint16_t *cols, uint16_t *rows);
 } ChardevClass;
 
 Chardev *qemu_chardev_new(const char *id, const char *typename,
-- 
2.27.0

[PATCH 3/6] chardev: add support for notifying about terminal resizes

[Szymon Lukasz]

Add a new chardev event, CHR_EVENT_RESIZE, which a backend should
trigger if detects the size of the connected terminal changed.

Signed-off-by: Szymon Lukasz <noh4hss@gmail.com>
---
 backends/cryptodev-vhost-user.c | 1 +
 chardev/char.c                  | 1 +
 hw/block/vhost-user-blk.c       | 1 +
 hw/char/terminal3270.c          | 1 +
 hw/char/virtio-console.c        | 1 +
 hw/ipmi/ipmi_bmc_extern.c       | 1 +
 hw/usb/ccid-card-passthru.c     | 1 +
 hw/usb/dev-serial.c             | 1 +
 hw/usb/redirect.c               | 1 +
 include/chardev/char.h          | 1 +
 monitor/hmp.c                   | 1 +
 monitor/qmp.c                   | 1 +
 net/vhost-user.c                | 1 +
 13 files changed, 13 insertions(+)

diff --git a/backends/cryptodev-vhost-user.c b/backends/cryptodev-vhost-user.c
index 8b8cbc4223..bbf8ad426a 100644
--- a/backends/cryptodev-vhost-user.c
+++ b/backends/cryptodev-vhost-user.c
@@ -174,6 +174,7 @@ static void cryptodev_vhost_user_event(void *opaque, QEMUChrEvent event)
     case CHR_EVENT_BREAK:
     case CHR_EVENT_MUX_IN:
     case CHR_EVENT_MUX_OUT:
+    case CHR_EVENT_RESIZE:
         /* Ignore */
         break;
     }
diff --git a/chardev/char.c b/chardev/char.c
index e3051295ac..904f8bf6e3 100644
--- a/chardev/char.c
+++ b/chardev/char.c
@@ -74,6 +74,7 @@ void qemu_chr_be_event(Chardev *s, QEMUChrEvent event)
     case CHR_EVENT_BREAK:
     case CHR_EVENT_MUX_IN:
     case CHR_EVENT_MUX_OUT:
+    case CHR_EVENT_RESIZE:
         /* Ignore */
         break;
     }
diff --git a/hw/block/vhost-user-blk.c b/hw/block/vhost-user-blk.c
index a00b854736..1a656a27c3 100644
--- a/hw/block/vhost-user-blk.c
+++ b/hw/block/vhost-user-blk.c
@@ -403,6 +403,7 @@ static void vhost_user_blk_event(void *opaque, QEMUChrEvent event)
     case CHR_EVENT_BREAK:
     case CHR_EVENT_MUX_IN:
     case CHR_EVENT_MUX_OUT:
+    case CHR_EVENT_RESIZE:
         /* Ignore */
         break;
     }
diff --git a/hw/char/terminal3270.c b/hw/char/terminal3270.c
index 2c47ebf007..eadccbb617 100644
--- a/hw/char/terminal3270.c
+++ b/hw/char/terminal3270.c
@@ -169,6 +169,7 @@ static void chr_event(void *opaque, QEMUChrEvent event)
     case CHR_EVENT_BREAK:
     case CHR_EVENT_MUX_IN:
     case CHR_EVENT_MUX_OUT:
+    case CHR_EVENT_RESIZE:
         /* Ignore */
         break;
     }
diff --git a/hw/char/virtio-console.c b/hw/char/virtio-console.c
index 4f46753ea3..97b9240ef5 100644
--- a/hw/char/virtio-console.c
+++ b/hw/char/virtio-console.c
@@ -165,6 +165,7 @@ static void chr_event(void *opaque, QEMUChrEvent event)
     case CHR_EVENT_BREAK:
     case CHR_EVENT_MUX_IN:
     case CHR_EVENT_MUX_OUT:
+    case CHR_EVENT_RESIZE:
         /* Ignore */
         break;
     }
diff --git a/hw/ipmi/ipmi_bmc_extern.c b/hw/ipmi/ipmi_bmc_extern.c
index f9a13e0a44..9562584309 100644
--- a/hw/ipmi/ipmi_bmc_extern.c
+++ b/hw/ipmi/ipmi_bmc_extern.c
@@ -439,6 +439,7 @@ static void chr_event(void *opaque, QEMUChrEvent event)
     case CHR_EVENT_BREAK:
     case CHR_EVENT_MUX_IN:
     case CHR_EVENT_MUX_OUT:
+    case CHR_EVENT_RESIZE:
         /* Ignore */
         break;
     }
diff --git a/hw/usb/ccid-card-passthru.c b/hw/usb/ccid-card-passthru.c
index bb325dbc4a..3c26b16ed0 100644
--- a/hw/usb/ccid-card-passthru.c
+++ b/hw/usb/ccid-card-passthru.c
@@ -321,6 +321,7 @@ static void ccid_card_vscard_event(void *opaque, QEMUChrEvent event)
     case CHR_EVENT_MUX_IN:
     case CHR_EVENT_MUX_OUT:
     case CHR_EVENT_CLOSED:
+    case CHR_EVENT_RESIZE:
         /* Ignore */
         break;
     }
diff --git a/hw/usb/dev-serial.c b/hw/usb/dev-serial.c
index 7e50e3ba47..e8e960d0e6 100644
--- a/hw/usb/dev-serial.c
+++ b/hw/usb/dev-serial.c
@@ -507,6 +507,7 @@ static void usb_serial_event(void *opaque, QEMUChrEvent event)
             break;
         case CHR_EVENT_MUX_IN:
         case CHR_EVENT_MUX_OUT:
+        case CHR_EVENT_RESIZE:
             /* Ignore */
             break;
     }
diff --git a/hw/usb/redirect.c b/hw/usb/redirect.c
index 417a60a2e6..b716c4fdd7 100644
--- a/hw/usb/redirect.c
+++ b/hw/usb/redirect.c
@@ -1383,6 +1383,7 @@ static void usbredir_chardev_event(void *opaque, QEMUChrEvent event)
     case CHR_EVENT_BREAK:
     case CHR_EVENT_MUX_IN:
     case CHR_EVENT_MUX_OUT:
+    case CHR_EVENT_RESIZE:
         /* Ignore */
         break;
     }
diff --git a/include/chardev/char.h b/include/chardev/char.h
index fb20707917..c3d108ce82 100644
--- a/include/chardev/char.h
+++ b/include/chardev/char.h
@@ -22,6 +22,7 @@ typedef enum {
     CHR_EVENT_OPENED, /* new connection established */
     CHR_EVENT_MUX_IN, /* mux-focus was set to this terminal */
     CHR_EVENT_MUX_OUT, /* mux-focus will move on */
+    CHR_EVENT_RESIZE, /* the terminal size of the chardev changed */
     CHR_EVENT_CLOSED /* connection closed.  NOTE: currently this event
                       * is only bound to the read port of the chardev.
                       * Normally the read port and write port of a
diff --git a/monitor/hmp.c b/monitor/hmp.c
index d598dd02bb..020be03d61 100644
--- a/monitor/hmp.c
+++ b/monitor/hmp.c
@@ -1373,6 +1373,7 @@ static void monitor_event(void *opaque, QEMUChrEvent event)
         break;
 
     case CHR_EVENT_BREAK:
+    case CHR_EVENT_RESIZE:
         /* Ignored */
         break;
     }
diff --git a/monitor/qmp.c b/monitor/qmp.c
index d433ceae5b..58aecb475b 100644
--- a/monitor/qmp.c
+++ b/monitor/qmp.c
@@ -371,6 +371,7 @@ static void monitor_qmp_event(void *opaque, QEMUChrEvent event)
     case CHR_EVENT_BREAK:
     case CHR_EVENT_MUX_IN:
     case CHR_EVENT_MUX_OUT:
+    case CHR_EVENT_RESIZE:
         /* Ignore */
         break;
     }
diff --git a/net/vhost-user.c b/net/vhost-user.c
index 17532daaf3..e30cbe74bd 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -297,6 +297,7 @@ static void net_vhost_user_event(void *opaque, QEMUChrEvent event)
     case CHR_EVENT_BREAK:
     case CHR_EVENT_MUX_IN:
     case CHR_EVENT_MUX_OUT:
+    case CHR_EVENT_RESIZE:
         /* Ignore */
         break;
     }
-- 
2.27.0

[PATCH 4/6] char-stdio: add support for the terminal size

[Szymon Lukasz]

Implement chr_get_winsize for the stdio backend
and trigger CHR_EVENT_RESIZE upon SIGWINCH delivery.

Signed-off-by: Szymon Lukasz <noh4hss@gmail.com>
---
 chardev/char-stdio.c | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/chardev/char-stdio.c b/chardev/char-stdio.c
index 82eaebc1db..ab14edffc1 100644
--- a/chardev/char-stdio.c
+++ b/chardev/char-stdio.c
@@ -34,7 +34,9 @@
 #include "chardev/char-win-stdio.h"
 #else
 #include <termios.h>
+#include <sys/ioctl.h>
 #include "chardev/char-fd.h"
+#include "qemu/main-loop.h"
 #endif
 
 #ifndef _WIN32
@@ -45,6 +47,13 @@ static bool stdio_in_use;
 static bool stdio_allow_signal;
 static bool stdio_echo_state;
 
+typedef struct {
+    FDChardev parent;
+    Notifier resize_notifier;
+} StdioChardev;
+
+#define STDIO_CHARDEV(obj) OBJECT_CHECK(StdioChardev, (obj), TYPE_CHARDEV_STDIO)
+
 static void term_exit(void)
 {
     if (stdio_in_use) {
@@ -82,11 +91,31 @@ static void term_stdio_handler(int sig)
     qemu_chr_set_echo_stdio(NULL, stdio_echo_state);
 }
 
+static int qemu_chr_get_winsize_stdio(Chardev *chr, uint16_t *cols, uint16_t *rows)
+{
+    struct winsize ws;
+
+    if (ioctl(1, TIOCGWINSZ, &ws) < 0) {
+        return -1;
+    }
+
+    *cols = ws.ws_col;
+    *rows = ws.ws_row;
+    return 0;
+}
+
+static void term_resize_notify(Notifier *n, void *data)
+{
+    StdioChardev *s = container_of(n, StdioChardev, resize_notifier);
+    qemu_chr_be_event(CHARDEV(s), CHR_EVENT_RESIZE);
+}
+
 static void qemu_chr_open_stdio(Chardev *chr,
                                 ChardevBackend *backend,
                                 bool *be_opened,
                                 Error **errp)
 {
+    StdioChardev *s = STDIO_CHARDEV(chr);
     ChardevStdio *opts = backend->u.stdio.data;
     struct sigaction act;
 
@@ -116,6 +145,9 @@ static void qemu_chr_open_stdio(Chardev *chr,
         stdio_allow_signal = opts->signal;
     }
     qemu_chr_set_echo_stdio(chr, false);
+
+    s->resize_notifier.notify = term_resize_notify;
+    sigwinch_add_notifier(&s->resize_notifier);
 }
 #endif
 
@@ -139,6 +171,7 @@ static void char_stdio_class_init(ObjectClass *oc, void *data)
 #ifndef _WIN32
     cc->open = qemu_chr_open_stdio;
     cc->chr_set_echo = qemu_chr_set_echo_stdio;
+    cc->chr_get_winsize = qemu_chr_get_winsize_stdio;
 #endif
 }
 
@@ -155,6 +188,7 @@ static const TypeInfo char_stdio_type_info = {
     .parent = TYPE_CHARDEV_WIN_STDIO,
 #else
     .parent = TYPE_CHARDEV_FD,
+    .instance_size = sizeof(StdioChardev),
 #endif
     .instance_finalize = char_stdio_finalize,
     .class_init = char_stdio_class_init,
-- 
2.27.0

[PATCH 5/6] virtio-serial-bus: add terminal resize messages

[Szymon Lukasz]

Implement the part of the virtio spec that allows to notify the virtio
driver about terminal resizes. The virtio spec contains two methods to
achieve that:

For legacy drivers, we have only one port and we put the terminal size
in the config space and inject the config changed interrupt.

For multiport devices, we use the control virtqueue to send a packet
containing the terminal size. Note that the Linux kernel expects
the fields indicating the number of rows and columns in a packet to be
in a different order than the one specified in the current version of
the virtio spec. We follow the Linux implementation, so hopefully there
is no implementation of this functionality conforming to the spec.

Signed-off-by: Szymon Lukasz <noh4hss@gmail.com>
---
 hw/char/trace-events              |  1 +
 hw/char/virtio-serial-bus.c       | 41 +++++++++++++++++++++++++++++--
 include/hw/virtio/virtio-serial.h |  5 ++++
 3 files changed, 45 insertions(+), 2 deletions(-)

diff --git a/hw/char/trace-events b/hw/char/trace-events
index d20eafd56f..be40df47ea 100644
--- a/hw/char/trace-events
+++ b/hw/char/trace-events
@@ -10,6 +10,7 @@ serial_ioport_write(uint16_t addr, uint8_t value) "write addr 0x%02x val 0x%02x"
 
 # virtio-serial-bus.c
 virtio_serial_send_control_event(unsigned int port, uint16_t event, uint16_t value) "port %u, event %u, value %u"
+virtio_serial_send_console_resize(unsigned int port, uint16_t cols, uint16_t rows) "port %u, cols %u, rows %u"
 virtio_serial_throttle_port(unsigned int port, bool throttle) "port %u, throttle %d"
 virtio_serial_handle_control_message(uint16_t event, uint16_t value) "event %u, value %u"
 virtio_serial_handle_control_message_port(unsigned int port) "port %u"
diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
index 262089c0c9..9d99161e13 100644
--- a/hw/char/virtio-serial-bus.c
+++ b/hw/char/virtio-serial-bus.c
@@ -261,6 +261,42 @@ static size_t send_control_event(VirtIOSerial *vser, uint32_t port_id,
     return send_control_msg(vser, &cpkt, sizeof(cpkt));
 }
 
+/*
+ * This struct should be added to the Linux kernel uapi headers
+ * and later imported to standard-headers/linux/virtio_console.h
+ */
+struct virtio_console_resize {
+    __virtio16 rows;
+    __virtio16 cols;
+};
+
+void virtio_serial_send_console_resize(VirtIOSerialPort *port,
+                                       uint16_t cols, uint16_t rows)
+{
+    VirtIOSerial *vser = port->vser;
+    VirtIODevice *vdev = VIRTIO_DEVICE(vser);
+
+    if (virtio_vdev_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT)) {
+        struct {
+            struct virtio_console_control control;
+            struct virtio_console_resize resize;
+        } buffer;
+
+        virtio_stl_p(vdev, &buffer.control.id, port->id);
+        virtio_stw_p(vdev, &buffer.control.event, VIRTIO_CONSOLE_RESIZE);
+        virtio_stw_p(vdev, &buffer.resize.cols, cols);
+        virtio_stw_p(vdev, &buffer.resize.rows, rows);
+
+        trace_virtio_serial_send_console_resize(port->id, cols, rows);
+        send_control_msg(vser, &buffer, sizeof(buffer));
+
+    } else if (virtio_vdev_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE)) {
+        vser->port0_cols = cols;
+        vser->port0_rows = rows;
+        virtio_notify_config(vdev);
+    }
+}
+
 /* Functions for use inside qemu to open and read from/write to ports */
 int virtio_serial_open(VirtIOSerialPort *port)
 {
@@ -559,6 +595,7 @@ static uint64_t get_features(VirtIODevice *vdev, uint64_t features,
     vser = VIRTIO_SERIAL(vdev);
 
     features |= vser->host_features;
+    virtio_add_feature(&features, VIRTIO_CONSOLE_F_SIZE);
     if (vser->bus.max_nr_ports > 1) {
         virtio_add_feature(&features, VIRTIO_CONSOLE_F_MULTIPORT);
     }
@@ -572,8 +609,8 @@ static void get_config(VirtIODevice *vdev, uint8_t *config_data)
     struct virtio_console_config *config =
         (struct virtio_console_config *)config_data;
 
-    config->cols = 0;
-    config->rows = 0;
+    config->cols = virtio_tswap16(vdev, vser->port0_cols);
+    config->rows = virtio_tswap16(vdev, vser->port0_rows);
     config->max_nr_ports = virtio_tswap32(vdev,
                                           vser->serial.max_virtserial_ports);
 }
diff --git a/include/hw/virtio/virtio-serial.h b/include/hw/virtio/virtio-serial.h
index ed3e916b68..1d6436c0b1 100644
--- a/include/hw/virtio/virtio-serial.h
+++ b/include/hw/virtio/virtio-serial.h
@@ -188,6 +188,8 @@ struct VirtIOSerial {
     virtio_serial_conf serial;
 
     uint64_t host_features;
+
+    uint16_t port0_cols, port0_rows;
 };
 
 /* Interface to the virtio-serial bus */
@@ -222,6 +224,9 @@ size_t virtio_serial_guest_ready(VirtIOSerialPort *port);
  */
 void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle);
 
+void virtio_serial_send_console_resize(VirtIOSerialPort *port,
+                                       uint16_t cols, uint16_t rows);
+
 #define TYPE_VIRTIO_SERIAL "virtio-serial-device"
 #define VIRTIO_SERIAL(obj) \
         OBJECT_CHECK(VirtIOSerial, (obj), TYPE_VIRTIO_SERIAL)
-- 
2.27.0

[PATCH 6/6] virtio-console: notify the guest about terminal resizes

[Szymon Lukasz]

If a virtio serial port is a console port forward terminal resize
messages from the chardev backend to the guest.

Signed-off-by: Szymon Lukasz <noh4hss@gmail.com>
---
 hw/char/virtio-console.c | 64 +++++++++++++++++++++++++++++++++++++---
 1 file changed, 60 insertions(+), 4 deletions(-)

diff --git a/hw/char/virtio-console.c b/hw/char/virtio-console.c
index 97b9240ef5..1ea06aad08 100644
--- a/hw/char/virtio-console.c
+++ b/hw/char/virtio-console.c
@@ -29,6 +29,7 @@ typedef struct VirtConsole {
 
     CharBackend chr;
     guint watch;
+    uint16_t cols, rows;
 } VirtConsole;
 
 /*
@@ -104,6 +105,36 @@ static ssize_t flush_buf(VirtIOSerialPort *port,
     return ret;
 }
 
+static void virtconsole_send_resize(VirtIOSerialPort *port)
+{
+    uint16_t cols, rows;
+    VirtConsole *vcon = VIRTIO_CONSOLE(port);
+
+    /*
+     * We probably shouldn't send these messages before
+     * we told the guest it is a console port (which we do
+     * by sending VIRTIO_CONSOLE_CONSOLE_PORT message).
+     * Instead of adding a new field to the device state
+     * lets just use the guest_connected field for that purpose
+     * since the guest should not care about the terminal size
+     * before opening the port.
+     */
+    if (!port->guest_connected) {
+        return;
+    }
+
+    if (qemu_chr_fe_get_winsize(&vcon->chr, &cols, &rows) < 0) {
+        cols = 0;
+        rows = 0;
+    }
+
+    if (cols != vcon->cols || rows != vcon->rows) {
+        vcon->cols = cols;
+        vcon->rows = rows;
+        virtio_serial_send_console_resize(port, cols, rows);
+    }
+}
+
 /* Callback function that's called when the guest opens/closes the port */
 static void set_guest_connected(VirtIOSerialPort *port, int guest_connected)
 {
@@ -111,7 +142,9 @@ static void set_guest_connected(VirtIOSerialPort *port, int guest_connected)
     DeviceState *dev = DEVICE(port);
     VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 
-    if (!k->is_console) {
+    if (k->is_console) {
+        virtconsole_send_resize(port);
+    } else {
         qemu_chr_fe_set_open(&vcon->chr, guest_connected);
     }
 
@@ -171,6 +204,22 @@ static void chr_event(void *opaque, QEMUChrEvent event)
     }
 }
 
+static void chr_event_console(void *opaque, QEMUChrEvent event)
+{
+    VirtConsole *vcon = opaque;
+    VirtIOSerialPort *port = VIRTIO_SERIAL_PORT(vcon);
+
+    switch (event) {
+    case CHR_EVENT_OPENED:
+    case CHR_EVENT_RESIZE:
+        trace_virtio_console_chr_event(port->id, event);
+        virtconsole_send_resize(port);
+        break;
+    default:
+        break;
+    }
+}
+
 static int chr_be_change(void *opaque)
 {
     VirtConsole *vcon = opaque;
@@ -179,7 +228,9 @@ static int chr_be_change(void *opaque)
 
     if (k->is_console) {
         qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
-                                 NULL, chr_be_change, vcon, NULL, true);
+                                 chr_event_console, chr_be_change,
+                                 vcon, NULL, true);
+        virtconsole_send_resize(port);
     } else {
         qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
                                  chr_event, chr_be_change, vcon, NULL, false);
@@ -207,7 +258,7 @@ static void virtconsole_enable_backend(VirtIOSerialPort *port, bool enable)
         VirtIOSerialPortClass *k = VIRTIO_SERIAL_PORT_GET_CLASS(port);
 
         qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
-                                 k->is_console ? NULL : chr_event,
+                                 k->is_console ? chr_event_console : chr_event,
                                  chr_be_change, vcon, NULL, false);
     } else {
         qemu_chr_fe_set_handlers(&vcon->chr, NULL, NULL, NULL,
@@ -227,6 +278,11 @@ static void virtconsole_realize(DeviceState *dev, Error **errp)
         return;
     }
 
+    if (k->is_console) {
+        vcon->cols = (uint16_t) -1;
+        vcon->rows = (uint16_t) -1;
+    }
+
     if (qemu_chr_fe_backend_connected(&vcon->chr)) {
         /*
          * For consoles we don't block guest data transfer just
@@ -239,7 +295,7 @@ static void virtconsole_realize(DeviceState *dev, Error **errp)
          */
         if (k->is_console) {
             qemu_chr_fe_set_handlers(&vcon->chr, chr_can_read, chr_read,
-                                     NULL, chr_be_change,
+                                     chr_event_console, chr_be_change,
                                      vcon, NULL, true);
             virtio_serial_open(port);
         } else {
-- 
2.27.0

Re: [PATCH 5/6] virtio-serial-bus: add terminal resize messages

[Michael S. Tsirkin]

On Sun, Jun 21, 2020 at 06:21:31PM +0200, Szymon Lukasz wrote:
> Implement the part of the virtio spec that allows to notify the virtio
> driver about terminal resizes. The virtio spec contains two methods to
> achieve that:
> 
> For legacy drivers, we have only one port and we put the terminal size
> in the config space and inject the config changed interrupt.
> 
> For multiport devices, we use the control virtqueue to send a packet
> containing the terminal size. Note that the Linux kernel expects
> the fields indicating the number of rows and columns in a packet to be
> in a different order than the one specified in the current version of
> the virtio spec. We follow the Linux implementation, so hopefully there
> is no implementation of this functionality conforming to the spec.
> 
> Signed-off-by: Szymon Lukasz <noh4hss@gmail.com>
> ---
>  hw/char/trace-events              |  1 +
>  hw/char/virtio-serial-bus.c       | 41 +++++++++++++++++++++++++++++--
>  include/hw/virtio/virtio-serial.h |  5 ++++
>  3 files changed, 45 insertions(+), 2 deletions(-)
> 
> diff --git a/hw/char/trace-events b/hw/char/trace-events
> index d20eafd56f..be40df47ea 100644
> --- a/hw/char/trace-events
> +++ b/hw/char/trace-events
> @@ -10,6 +10,7 @@ serial_ioport_write(uint16_t addr, uint8_t value) "write addr 0x%02x val 0x%02x"
>  
>  # virtio-serial-bus.c
>  virtio_serial_send_control_event(unsigned int port, uint16_t event, uint16_t value) "port %u, event %u, value %u"
> +virtio_serial_send_console_resize(unsigned int port, uint16_t cols, uint16_t rows) "port %u, cols %u, rows %u"
>  virtio_serial_throttle_port(unsigned int port, bool throttle) "port %u, throttle %d"
>  virtio_serial_handle_control_message(uint16_t event, uint16_t value) "event %u, value %u"
>  virtio_serial_handle_control_message_port(unsigned int port) "port %u"
> diff --git a/hw/char/virtio-serial-bus.c b/hw/char/virtio-serial-bus.c
> index 262089c0c9..9d99161e13 100644
> --- a/hw/char/virtio-serial-bus.c
> +++ b/hw/char/virtio-serial-bus.c
> @@ -261,6 +261,42 @@ static size_t send_control_event(VirtIOSerial *vser, uint32_t port_id,
>      return send_control_msg(vser, &cpkt, sizeof(cpkt));
>  }
>  
> +/*
> + * This struct should be added to the Linux kernel uapi headers
> + * and later imported to standard-headers/linux/virtio_console.h
> + */
> +struct virtio_console_resize {
> +    __virtio16 rows;
> +    __virtio16 cols;
> +};
> +
> +void virtio_serial_send_console_resize(VirtIOSerialPort *port,
> +                                       uint16_t cols, uint16_t rows)
> +{
> +    VirtIOSerial *vser = port->vser;
> +    VirtIODevice *vdev = VIRTIO_DEVICE(vser);
> +
> +    if (virtio_vdev_has_feature(vdev, VIRTIO_CONSOLE_F_MULTIPORT)) {
> +        struct {
> +            struct virtio_console_control control;
> +            struct virtio_console_resize resize;
> +        } buffer;
> +
> +        virtio_stl_p(vdev, &buffer.control.id, port->id);
> +        virtio_stw_p(vdev, &buffer.control.event, VIRTIO_CONSOLE_RESIZE);
> +        virtio_stw_p(vdev, &buffer.resize.cols, cols);
> +        virtio_stw_p(vdev, &buffer.resize.rows, rows);
> +
> +        trace_virtio_serial_send_console_resize(port->id, cols, rows);
> +        send_control_msg(vser, &buffer, sizeof(buffer));
> +
> +    } else if (virtio_vdev_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE)) {
> +        vser->port0_cols = cols;
> +        vser->port0_rows = rows;
> +        virtio_notify_config(vdev);
> +    }
> +}
> +
>  /* Functions for use inside qemu to open and read from/write to ports */
>  int virtio_serial_open(VirtIOSerialPort *port)
>  {
> @@ -559,6 +595,7 @@ static uint64_t get_features(VirtIODevice *vdev, uint64_t features,
>      vser = VIRTIO_SERIAL(vdev);
>  
>      features |= vser->host_features;
> +    virtio_add_feature(&features, VIRTIO_CONSOLE_F_SIZE);
>      if (vser->bus.max_nr_ports > 1) {
>          virtio_add_feature(&features, VIRTIO_CONSOLE_F_MULTIPORT);
>      }

Unconditonally adding a feature bit like that will break cross-version
migration. You need to add it through a bit property and
the disable for existing machine types.


> @@ -572,8 +609,8 @@ static void get_config(VirtIODevice *vdev, uint8_t *config_data)
>      struct virtio_console_config *config =
>          (struct virtio_console_config *)config_data;
>  
> -    config->cols = 0;
> -    config->rows = 0;
> +    config->cols = virtio_tswap16(vdev, vser->port0_cols);
> +    config->rows = virtio_tswap16(vdev, vser->port0_rows);
>      config->max_nr_ports = virtio_tswap32(vdev,
>                                            vser->serial.max_virtserial_ports);
>  }
> diff --git a/include/hw/virtio/virtio-serial.h b/include/hw/virtio/virtio-serial.h
> index ed3e916b68..1d6436c0b1 100644
> --- a/include/hw/virtio/virtio-serial.h
> +++ b/include/hw/virtio/virtio-serial.h
> @@ -188,6 +188,8 @@ struct VirtIOSerial {
>      virtio_serial_conf serial;
>  
>      uint64_t host_features;
> +
> +    uint16_t port0_cols, port0_rows;
>  };
>  
>  /* Interface to the virtio-serial bus */
> @@ -222,6 +224,9 @@ size_t virtio_serial_guest_ready(VirtIOSerialPort *port);
>   */
>  void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle);
>  
> +void virtio_serial_send_console_resize(VirtIOSerialPort *port,
> +                                       uint16_t cols, uint16_t rows);
> +
>  #define TYPE_VIRTIO_SERIAL "virtio-serial-device"
>  #define VIRTIO_SERIAL(obj) \
>          OBJECT_CHECK(VirtIOSerial, (obj), TYPE_VIRTIO_SERIAL)
> -- 
> 2.27.0