Filip Hejsek <filip.hej...@gmail.com> writes:
> On Fri, 2025-09-12 at 16:01 +0200, Markus Armbruster wrote:
>> Cc: libvirt
>>
>> Filip Hejsek <filip.hej...@gmail.com> writes:
>>
>> > From: Szymon Lukasz <noh4...@gmail.com>
>> >
>> > The managment software can use this command to notify QEMU about the
>> > size of the terminal connected to a chardev, QEMU can then forward this
>> > information to the guest if the chardev is connected to a virtio console
>> > device.
>> >
>> > Signed-off-by: Szymon Lukasz <noh4...@gmail.com>
>> > Suggested-by: Daniel P. Berrangé <berra...@redhat.com>
>> > Signed-off-by: Filip Hejsek <filip.hej...@gmail.com>
>> > ---
>> > chardev/char.c | 14 ++++++++++++++
>> > qapi/char.json | 22 ++++++++++++++++++++++
>> > 2 files changed, 36 insertions(+)
>> >
>> > diff --git a/chardev/char.c b/chardev/char.c
>> > index
>> > b45d79cb9b57643827eb7479257fdda2cf6b0434..6e3ade98614c949be8041ec5905a490ff536dee9
>> > 100644
>> > --- a/chardev/char.c
>> > +++ b/chardev/char.c
>> > @@ -1269,6 +1269,20 @@ bool qmp_add_client_char(int fd, bool has_skipauth,
>> > bool skipauth,
>> > return true;
>> > }
>> >
>> > +void qmp_chardev_resize(const char *id, uint16_t cols, uint16_t rows,
>> > + Error **errp)
>> > +{
>> > + Chardev *chr;
>> > +
>> > + chr = qemu_chr_find(id);
>> > + if (chr == NULL) {
>> > + error_setg(errp, "Chardev '%s' not found", id);
>> > + return;
>> > + }
>> > +
>> > + qemu_chr_resize(chr, cols, rows);
>> > +}
>> > +
>> > /*
>> > * Add a timeout callback for the chardev (in milliseconds), return
>> > * the GSource object created. Please use this to add timeout hook for
>> > diff --git a/qapi/char.json b/qapi/char.json
>> > index
>> > f0a53f742c8bee24c377551803a864fd36ac78cf..0a26c5eee6b71bc5de127a91b253cc69a9fe8ce6
>> > 100644
>> > --- a/qapi/char.json
>> > +++ b/qapi/char.json
>> > @@ -874,6 +874,28 @@
>> > { 'command': 'chardev-send-break',
>> > 'data': { 'id': 'str' } }
>> >
>> > +##
>> > +# @chardev-resize:
>>
>> This name doesn't tell me what is being resized. PATCH 04 uses
>> "winsize", which is better. The (losely) related SIGWINCH suggests
>> "window change" or "window size change". Below, you use "terminal
>> size".
>
> How about chardev-console-resize? That would match the name of the
> virtio event (VIRTIO_CONSOLE_RESIZE).
Not bad. It could become slightly bad if we make devices other than
"consoles" make us of it. Would that be possible?
>> > +#
>> > +# Notifies a chardev about the current size of the terminal connected
>> > +# to this chardev.
>>
>> Yes, but what is it good for? Your commit message tells: "managment
>> software can use this command to notify QEMU about the size of the
>> terminal connected to a chardev, QEMU can then forward this information
>> to the guest if the chardev is connected to a virtio console device."
>
> How about:
>
> Notifies a chardev about the current size of the terminal connected
> to this chardev. The information will be forwarded to the guest if
> the chardev is connected to a virtio console device.
Works for me.
>> > +#
>> > +# @id: the chardev's ID, must exist
>> > +# @cols: the number of columns
>> > +# @rows: the number of rows
>>
>> Blank lines between the argument descriptions, bease.
>>
>> What's the initial size?
>
> 0x0
A clearly invalid size. I guess it effectively means "unknown size".
Should we document that?
>> Do we need a way to query the size?
>
> I don't think it is necessary. What would be the usecase for that?
I don't know, but it's my standard question when I see an interface to
set something without an interface to get it. Its purpose is to make us
think, not to make us at the get blindly.
>> > +#
>> > +# Since: 10.2
>> > +#
>> > +# .. qmp-example::
>> > +#
>> > +# -> { "execute": "chardev-resize", "arguments": { "id": "foo",
>> > "cols": 80, "rows": 24 } }
>> > +# <- { "return": {} }
>> > +##
>> > +{ 'command': 'chardev-resize',
>> > + 'data': { 'id': 'str',
>> > + 'cols': 'uint16',
>> > + 'rows': 'uint16' } }
>> > +
>> > ##
>> > # @VSERPORT_CHANGE:
>> > #
