Hi

On Wed, Oct 21, 2026 at 6:24 PM Filip Hejsek <[email protected]> wrote:
>
> On Tue, 2026-10-20 at 19:56 +0400, [email protected] wrote:
> > > Implement the part of the virtio spec that allows to notify the virtio
> > > driver about terminal resizes. Gate the new resize support behind the
> > > console-size property, which defaults to off. To implement the property,
> > > restore VirtIOSerial::host_features (previously removed by commit
> > > d0660e5b7fc7e97926232d13d2500a16df32b310).
> > >
> > > The virtio spec contains two methods to inform the guest about console
> > > size:
> > >
> > > 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. Unfortunately, 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 running an
> > > old guest kernel, 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]>
> > > Message-ID: <[email protected]>
> > > ---
> > >  hw/char/trace-events              |  1 +
> > >  hw/char/virtio-serial-bus.c       | 81 
> > > ++++++++++++++++++++++++++++++++++++++-
> > >  include/hw/virtio/virtio-serial.h |  7 ++++
> > >  3 files changed, 87 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/hw/char/trace-events b/hw/char/trace-events
> > > index a3fcc772877a..e387c8853fcf 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 c36e18a4cfb5..882765ac88ab 100644
> > > --- a/hw/char/virtio-serial-bus.c
> > > +++ b/hw/char/virtio-serial-bus.c
> > > @@ -261,6 +261,68 @@ 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)) {
> >
> > it should probably gate on negotiated virtio_vdev_has_feature(vdev, 
> > VIRTIO_CONSOLE_F_SIZE) as well
>
> I think the patch is already merged [1]? I'm not familiar with all
> details of the QEMU development process. Should I address this in a
> follow-up commit?
>
> [1]: 
> https://lore.kernel.org/qemu-devel/[email protected]/

Indeed, so you should rebase your series. Make a new patch for it if
you agree with my review.

thanks


Reply via email to