On Sun, Sep 21, 2025 at 01:45:38AM +0200, Filip Hejsek wrote: > From: Szymon Lukasz <[email protected]> > > 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.
That kernel patch is being reverted: https://lore.kernel.org/lkml/[email protected]/ so this patch needs to use the historical ordering. That revert needs to go into linux -stable trees, and any recent distro that has picked up the recent swapped ordering in their kernels. > > Signed-off-by: Szymon Lukasz <[email protected]> > [Filip: swap rows/cols, console-size affects multiport too, > size config always updated, use use_multiport, move trace call] > Signed-off-by: Filip Hejsek <[email protected]> > --- > hw/char/trace-events | 1 + > hw/char/virtio-serial-bus.c | 51 > +++++++++++++++++++++++++++++++++++++-- > hw/core/machine.c | 4 ++- > include/hw/virtio/virtio-serial.h | 5 ++++ > 4 files changed, 58 insertions(+), 3 deletions(-) > > diff --git a/hw/char/trace-events b/hw/char/trace-events > index > 05a33036c12070242c2b193c19011839d623bec4..9a975ab1e2a525a9391d0f0a85ddbe80aa6361fc > 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 > 673c50f0be08ef9b7142c16eaf8e6e31c7a00ca5..30e3ec73a1733449b2505f231a3d2b3516ae4b4e > 100644 > --- a/hw/char/virtio-serial-bus.c > +++ b/hw/char/virtio-serial-bus.c > @@ -260,6 +260,51 @@ 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; > +}; > + > +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_has_feature(vser->host_features, VIRTIO_CONSOLE_F_SIZE)) { > + return; > + } > + > + trace_virtio_serial_send_console_resize(port->id, cols, rows); > + > + if (port->id == 0) { > + vser->port0_cols = cols; > + vser->port0_rows = rows; > + if (!use_multiport(vser) && > + virtio_vdev_has_feature(vdev, VIRTIO_CONSOLE_F_SIZE)) { > + virtio_notify_config(vdev); > + } > + } > + > + 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, cols); > + virtio_stw_p(vdev, &buffer.resize.rows, rows); > + > + send_control_msg(vser, &buffer, sizeof(buffer)); > + } > +} > + > /* Functions for use inside qemu to open and read from/write to ports */ > int virtio_serial_open(VirtIOSerialPort *port) > { > @@ -571,8 +616,8 @@ 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); > } > @@ -1158,6 +1203,8 @@ 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 > 38c949c4f2ce4a117cbfca62f56919711ce392b4..74a747ec6578c958b35e1f9712e5dbed7bca72e8 > 100644 > --- a/hw/core/machine.c > +++ b/hw/core/machine.c > @@ -37,7 +37,9 @@ > #include "hw/virtio/virtio-iommu.h" > #include "audio/audio.h" > > -GlobalProperty hw_compat_10_1[] = {}; > +GlobalProperty hw_compat_10_1[] = { > + { "virtio-serial-device", "console-size", "off" }, > +}; > const size_t hw_compat_10_1_len = G_N_ELEMENTS(hw_compat_10_1); > > GlobalProperty hw_compat_10_0[] = { > diff --git a/include/hw/virtio/virtio-serial.h > b/include/hw/virtio/virtio-serial.h > index > d87c62eab7a270809daf47f932a73dd1fa3d5a6e..81efa853f804a52866890a9ec2c71bfbcabca4a0 > 100644 > --- a/include/hw/virtio/virtio-serial.h > +++ b/include/hw/virtio/virtio-serial.h > @@ -187,6 +187,8 @@ struct VirtIOSerial { > virtio_serial_conf serial; > > uint64_t host_features; > + > + uint16_t port0_cols, port0_rows; > }; > > /* Interface to the virtio-serial bus */ > @@ -221,6 +223,9 @@ 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" > OBJECT_DECLARE_SIMPLE_TYPE(VirtIOSerial, VIRTIO_SERIAL) > > > -- > 2.51.0 > With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|
