From 4945aee74f494cc8a17ce1634b5200eb9ee227d2 Mon Sep 17 00:00:00 2001

From: Amit Shah <amit.shah@redhat.com>

Date: Wed, 20 Jan 2010 00:36:53 +0530

Subject: [PATCH 3/9] virtio-serial-bus: Maintain guest and host port open/close state

Via control channel messages, the guest can tell us whether a port got

opened or closed. Similarly, we can also indicate to the guest of host

port open/close events.

Signed-off-by: Amit Shah <amit.shah@redhat.com>

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

---

 hw/virtio-serial-bus.c |   94 ++++++++++++++++++++++++++++++++++++++++++++++++

 hw/virtio-serial.h     |    6 +++

 2 files changed, 100 insertions(+), 0 deletions(-)

diff --git a/hw/virtio-serial-bus.c b/hw/virtio-serial-bus.c

index 5132c9c..9af21df 100644

--- a/hw/virtio-serial-bus.c

+++ b/hw/virtio-serial-bus.c

@@ -66,6 +66,11 @@ static VirtIOSerialPort *find_port_by_vq(VirtIOSerial *vser, VirtQueue *vq)

     return NULL;

 }

+static bool use_multiport(VirtIOSerial *vser)

+{

+    return vser->vdev.features & (1 << VIRTIO_CONSOLE_F_MULTIPORT);

+}

+

 static size_t write_to_port(VirtIOSerialPort *port,

                             const uint8_t *buf, size_t size)

 {

@@ -139,11 +144,22 @@ static size_t send_control_event(VirtIOSerialPort *port, uint16_t event,

 /* Functions for use inside qemu to open and read from/write to ports */

 int virtio_serial_open(VirtIOSerialPort *port)

 {

+    /* Don't allow opening an already-open port */

+    if (port->host_connected) {

+        return 0;

+    }

+    /* Send port open notification to the guest */

+    port->host_connected = true;

+    send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);

+

     return 0;

 }

 int virtio_serial_close(VirtIOSerialPort *port)

 {

+    port->host_connected = false;

+    send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 0);

+

     return 0;

 }

@@ -151,6 +167,9 @@ int virtio_serial_close(VirtIOSerialPort *port)

 ssize_t virtio_serial_write(VirtIOSerialPort *port, const uint8_t *buf,

                             size_t size)

 {

+    if (!port || !port->host_connected || !port->guest_connected) {

+        return 0;

+    }

     return write_to_port(port, buf, size);

 }

@@ -167,6 +186,9 @@ size_t virtio_serial_guest_ready(VirtIOSerialPort *port)

         virtio_queue_empty(vq)) {

         return 0;

     }

+    if (use_multiport(port->vser) && !port->guest_connected) {

+        return 0;

+    }

     if (virtqueue_avail_bytes(vq, 4096, 0)) {

         return 4096;

@@ -203,6 +225,11 @@ static void handle_control_message(VirtIOSerial *vser, void *buf)

         if (port->is_console) {

             send_control_event(port, VIRTIO_CONSOLE_CONSOLE_PORT, 1);

         }

+

+        if (port->host_connected) {

+            send_control_event(port, VIRTIO_CONSOLE_PORT_OPEN, 1);

+        }

+

         /*

          * When the guest has asked us for this information it means

          * the guest is all setup and has its virtqueues

@@ -213,6 +240,19 @@ static void handle_control_message(VirtIOSerial *vser, void *buf)

             port->info->guest_ready(port);

         }

         break;

+

+    case VIRTIO_CONSOLE_PORT_OPEN:

+        port->guest_connected = cpkt.value;

+        if (cpkt.value && port->info->guest_open) {

+            /* Send the guest opened notification if an app is interested */

+            port->info->guest_open(port);

+        }

+

+        if (!cpkt.value && port->info->guest_close) {

+            /* Send the guest closed notification if an app is interested */

+            port->info->guest_close(port);

+        }

+        break;

     }

 }

@@ -300,6 +340,8 @@ static void set_config(VirtIODevice *vdev, const uint8_t *config_data)

 static void virtio_serial_save(QEMUFile *f, void *opaque)

 {

     VirtIOSerial *s = opaque;

+    VirtIOSerialPort *port;

+    uint32_t nr_active_ports;

     /* The virtio device */

     virtio_save(&s->vdev, f);

@@ -308,15 +350,41 @@ static void virtio_serial_save(QEMUFile *f, void *opaque)

     qemu_put_be16s(f, &s->config.cols);

     qemu_put_be16s(f, &s->config.rows);

     qemu_put_be32s(f, &s->config.nr_ports);

+

+    /* Items in struct VirtIOSerial */

+

+    /* Do this because we might have hot-unplugged some ports */

+    nr_active_ports = 0;

+    QTAILQ_FOREACH(port, &s->ports, next)

+        nr_active_ports++;

+

+    qemu_put_be32s(f, &nr_active_ports);

+

+    /*

+     * Items in struct VirtIOSerialPort.

+     */

+    QTAILQ_FOREACH(port, &s->ports, next) {

+        /*

+         * We put the port number because we may not have an active

+         * port at id 0 that's reserved for a console port, or in case

+         * of ports that might have gotten unplugged

+         */

+        qemu_put_be32s(f, &port->id);

+        qemu_put_byte(f, port->guest_connected);

+    }

 }

 static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)

 {

     VirtIOSerial *s = opaque;

+    VirtIOSerialPort *port;

+    uint32_t nr_active_ports;

+    unsigned int i;

     if (version_id > 2) {

         return -EINVAL;

     }

+

     /* The virtio device */

     virtio_load(&s->vdev, f);

@@ -329,6 +397,20 @@ static int virtio_serial_load(QEMUFile *f, void *opaque, int version_id)

     qemu_get_be16s(f, &s->config.rows);

     s->config.nr_ports = qemu_get_be32(f);

+    /* Items in struct VirtIOSerial */

+

+    qemu_get_be32s(f, &nr_active_ports);

+

+    /* Items in struct VirtIOSerialPort */

+    for (i = 0; i < nr_active_ports; i++) {

+        uint32_t id;

+

+        id = qemu_get_be32(f);

+        port = find_port_by_id(s, id);

+

+        port->guest_connected = qemu_get_byte(f);

+    }

+

     return 0;

 }

@@ -357,6 +439,10 @@ static void virtser_bus_dev_print(Monitor *mon, DeviceState *qdev, int indent)

     monitor_printf(mon, "%*s dev-prop-int: id: %u\n",

                    indent, "", port->id);

+    monitor_printf(mon, "%*s dev-prop-int: guest_connected: %d\n",

+                   indent, "", port->guest_connected);

+    monitor_printf(mon, "%*s dev-prop-int: host_connected: %d\n",

+                   indent, "", port->host_connected);

 }

 static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base)

@@ -390,6 +476,14 @@ static int virtser_port_qdev_init(DeviceState *qdev, DeviceInfo *base)

     port->id = plugging_port0 ? 0 : port->vser->config.nr_ports++;

+    if (!use_multiport(port->vser)) {

+        /*

+         * Allow writes to guest in this case; we have no way of

+         * knowing if a guest port is connected.

+         */

+        port->guest_connected = true;

+    }

+

     QTAILQ_INSERT_TAIL(&port->vser->ports, port, next);

     port->ivq = port->vser->ivqs[port->id];

     port->ovq = port->vser->ovqs[port->id];

diff --git a/hw/virtio-serial.h b/hw/virtio-serial.h

index fe8e357..d9c7acb 100644

--- a/hw/virtio-serial.h

+++ b/hw/virtio-serial.h

@@ -49,6 +49,7 @@ struct virtio_console_control {

 #define VIRTIO_CONSOLE_PORT_READY	0

 #define VIRTIO_CONSOLE_CONSOLE_PORT	1

 #define VIRTIO_CONSOLE_RESIZE		2

+#define VIRTIO_CONSOLE_PORT_OPEN	3

 /* == In-qemu interface == */

@@ -92,6 +93,11 @@ struct VirtIOSerialPort {

     /* Identify if this is a port that binds with hvc in the guest */

     uint8_t is_console;

+

+    /* Is the corresponding guest device open? */

+    bool guest_connected;

+    /* Is this device open for IO on the host? */

+    bool host_connected;

 };

 struct VirtIOSerialPortInfo {

-- 

1.6.2.5