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 old versions of the Linux kernel used an incorrect order for the fields (rows then cols instead of cols then rows), until it was fixed by commit 5326ab737a47278dbd16ed3ee7380b26c7056ddd. As a result, when using a Linux kernel older than 6.15, the number of rows and columns will be swapped. Based on a patch originally written by Szymon Lukasz <[email protected]>, but partially rewritten to fix various corner cases. Signed-off-by: Szymon Lukasz <[email protected]> Signed-off-by: Filip Hejsek <[email protected]> --- hw/char/trace-events | 1 + hw/char/virtio-serial-bus.c | 76 +++++++++++++++++++++++++++++++++++++-- hw/core/machine.c | 4 ++- include/hw/virtio/virtio-serial.h | 5 +++ 4 files changed, 83 insertions(+), 3 deletions(-) diff --git a/hw/char/trace-events b/hw/char/trace-events index 9e74be2c14..2416d4d04e 100644 --- a/hw/char/trace-events +++ b/hw/char/trace-events @@ -11,6 +11,7 @@ serial_update_parameters(uint64_t baudrate, char parity, int data_bits, int stop # 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 5ec5f5313b..6348eef3a2 100644 --- a/hw/char/virtio-serial-bus.c +++ b/hw/char/virtio-serial-bus.c @@ -260,6 +260,68 @@ 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 cols; + __virtio16 rows; +}; + +static void send_console_resize(VirtIOSerialPort *port) +{ + VirtIOSerial *vser = port->vser; + VirtIODevice *vdev = VIRTIO_DEVICE(vser); + + if (!virtio_has_feature(vser->host_features, VIRTIO_CONSOLE_F_SIZE)) { + return; + } + + trace_virtio_serial_send_console_resize(port->id, port->cols, port->rows); + + if (use_multiport(vser)) { + 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, port->cols); + virtio_stw_p(vdev, &buffer.resize.rows, port->rows); + + send_control_msg(vser, &buffer, sizeof(buffer)); + } +} + +void virtio_serial_resize_console(VirtIOSerialPort *port, + uint16_t cols, uint16_t rows) +{ + VirtIOSerial *vser = port->vser; + VirtIODevice *vdev = VIRTIO_DEVICE(vser); + + if (port->cols == cols && port->rows == rows) { + return; + } + + port->cols = cols; + port->rows = rows; + + if (port->id == 0 && !use_multiport(vser) && + virtio_vdev_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE)) { + virtio_notify_config(vdev); + } + + /* + * We will send these messages even before we told the guest that + * it is a console port (by sending VIRTIO_CONSOLE_CONSOLE_PORT + * message), but that should be fine as the guest will likely + * ignore them. + */ + send_console_resize(port); +} + /* Functions for use inside qemu to open and read from/write to ports */ int virtio_serial_open(VirtIOSerialPort *port) { @@ -408,6 +470,7 @@ static void handle_control_message(VirtIOSerial *vser, void *buf, size_t len) */ if (vsc->is_console) { send_control_event(vser, port->id, VIRTIO_CONSOLE_CONSOLE_PORT, 1); + send_console_resize(port); } if (port->name) { @@ -568,11 +631,18 @@ static uint64_t get_features(VirtIODevice *vdev, uint64_t features, static void get_config(VirtIODevice *vdev, uint8_t *config_data) { VirtIOSerial *vser = VIRTIO_SERIAL(vdev); + VirtIOSerialPort *port; struct virtio_console_config *config = (struct virtio_console_config *)config_data; - config->cols = 0; - config->rows = 0; + port = find_port_by_id(vser, 0); + if (port) { + config->cols = virtio_tswap16(vdev, port->cols); + config->rows = virtio_tswap16(vdev, port->rows); + } else { + config->cols = 0; + config->rows = 0; + } config->max_nr_ports = virtio_tswap32(vdev, vser->serial.max_virtserial_ports); } @@ -1158,6 +1228,8 @@ static const Property virtio_serial_properties[] = { 31), DEFINE_PROP_BIT64("emergency-write", VirtIOSerial, host_features, VIRTIO_CONSOLE_F_EMERG_WRITE, true), + DEFINE_PROP_BIT64("console-size", VirtIOSerial, host_features, + VIRTIO_CONSOLE_F_SIZE, true), }; static void virtio_serial_class_init(ObjectClass *klass, const void *data) diff --git a/hw/core/machine.c b/hw/core/machine.c index 6411e68856..50554b8900 100644 --- a/hw/core/machine.c +++ b/hw/core/machine.c @@ -38,7 +38,9 @@ #include "hw/acpi/generic_event_device.h" #include "qemu/audio.h" -GlobalProperty hw_compat_10_2[] = {}; +GlobalProperty hw_compat_10_2[] = { + { "virtio-serial-device", "console-size", "off" }, +}; const size_t hw_compat_10_2_len = G_N_ELEMENTS(hw_compat_10_2); GlobalProperty hw_compat_10_1[] = { diff --git a/include/hw/virtio/virtio-serial.h b/include/hw/virtio/virtio-serial.h index 60641860bf..bda6d5312a 100644 --- a/include/hw/virtio/virtio-serial.h +++ b/include/hw/virtio/virtio-serial.h @@ -145,6 +145,9 @@ struct VirtIOSerialPort { bool host_connected; /* Do apps not want to receive data? */ bool throttled; + + /* Terminal size reported to the guest. Only used for consoles. */ + uint16_t cols, rows; }; /* The virtio-serial bus on top of which the ports will ride as devices */ @@ -222,5 +225,7 @@ size_t virtio_serial_guest_ready(VirtIOSerialPort *port); */ void virtio_serial_throttle_port(VirtIOSerialPort *port, bool throttle); +void virtio_serial_resize_console(VirtIOSerialPort *port, + uint16_t cols, uint16_t rows); #endif -- 2.52.0
