virtio-serial-bus: Maintain guest and host port open/close state (6663a195) · Commits · SUMMER2020 / students / proj-2021291

hw/virtio-serial-bus.c

+94 −0

Original line number	Diff line number	Diff line
		@@ -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.guest_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;
		}
		}

		@@ -302,6 +342,8 @@ 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);
		@@ -310,15 +352,41 @@ 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);

		@@ -331,6 +399,20 @@ 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;
		}

		@@ -360,6 +442,10 @@ 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)
		@@ -393,6 +479,14 @@ 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];

hw/virtio-serial.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -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 {