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 <noh4...@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
