Re: [PATCH 1/2] ui: Allow injection of vnc display name

["Daniel P. Berrangé" <berrange@redhat.com>]

On Mon, Oct 21, 2024 at 03:14:39PM +0400, Marc-André Lureau wrote:
> Hi Roque
> 
> On Fri, Oct 18, 2024 at 1:53 AM Roque Arcudia Hernandez
> <roqueh@google.com> wrote:
> >
> > From: Andrew Keesler <ankeesler@google.com>
> >
> > Thanks to 72d277a7, 1ed2cb32, and others, EDID (Extended Display Identification
> > Data) is propagated by QEMU such that a virtual display presents legitimate
> > metadata (e.g., name, serial number, preferred resolutions, etc.) to its
> > connected guest.
> >
> > This change propagates an optional user-provided display name to
> > QemuConsole. Future changes will update downstream devices to leverage this
> > display name for various uses, the primary one being providing a custom EDID
> > name to guests. Future changes will also update other displays (e.g., spice)
> > with a similar option to propagate a display name to downstream devices.
> >
> > Currently, every virtio-gpu virtual display has the same name: "QEMU
> > Monitor". We hope to be able to inject the EDID name of virtual displays in
> > order to test guest behavior that is specific to display names. We provide the
> > ability to inject the display name from the display configuration as that most
> > closely resembles how real displays work (hardware displays contain static EDID
> > information that is provided to every connected host).
> >
> > It should also be noted that EDID names longer than 12 bytes will be truncated
> > per spec (I think?).
> >
> > Signed-off-by: Andrew Keesler <ankeesler@google.com>
> > Signed-off-by: Roque Arcudia Hernandez <roqueh@google.com>
> > ---
> >  include/ui/console.h | 1 +
> >  ui/console-priv.h    | 1 +
> >  ui/console.c         | 8 ++++++++
> >  ui/vnc.c             | 8 +++++++-
> >  4 files changed, 17 insertions(+), 1 deletion(-)
> >
> > diff --git a/include/ui/console.h b/include/ui/console.h
> > index 5832d52a8a..74ab03ed72 100644
> > --- a/include/ui/console.h
> > +++ b/include/ui/console.h
> > @@ -408,6 +408,7 @@ int qemu_console_get_index(QemuConsole *con);
> >  uint32_t qemu_console_get_head(QemuConsole *con);
> >  int qemu_console_get_width(QemuConsole *con, int fallback);
> >  int qemu_console_get_height(QemuConsole *con, int fallback);
> > +void qemu_console_set_name(QemuConsole *con, const char *name);
> >  /* Return the low-level window id for the console */
> >  int qemu_console_get_window_id(QemuConsole *con);
> >  /* Set the low-level window id for the console */
> > diff --git a/ui/console-priv.h b/ui/console-priv.h
> > index 43ceb8122f..9f2769843f 100644
> > --- a/ui/console-priv.h
> > +++ b/ui/console-priv.h
> > @@ -18,6 +18,7 @@ struct QemuConsole {
> >      Object parent;
> >
> >      int index;
> > +    const char *name;
> >      DisplayState *ds;
> >      DisplaySurface *surface;
> >      DisplayScanout scanout;
> > diff --git a/ui/console.c b/ui/console.c
> > index 5165f17125..f377fd8417 100644
> > --- a/ui/console.c
> > +++ b/ui/console.c
> > @@ -1452,6 +1452,14 @@ int qemu_console_get_height(QemuConsole *con, int fallback)
> >      }
> >  }
> >
> > +void qemu_console_set_name(QemuConsole *con, const char *name)
> > +{
> > +    if (con == NULL) {
> > +        return;
> > +    }
> > +    con->name = name;
> > +}
> > +
> >  int qemu_invalidate_text_consoles(void)
> >  {
> >      QemuConsole *s;
> > diff --git a/ui/vnc.c b/ui/vnc.c
> > index 93a8dbd253..7d6acc5c2e 100644
> > --- a/ui/vnc.c
> > +++ b/ui/vnc.c
> > @@ -3595,6 +3595,9 @@ static QemuOptsList qemu_vnc_opts = {
> >          },{
> >              .name = "power-control",
> >              .type = QEMU_OPT_BOOL,
> > +        },{
> > +            .name = "name",
> > +            .type = QEMU_OPT_STRING,
> >          },
> >          { /* end of list */ }
> >      },
> > @@ -4016,7 +4019,7 @@ void vnc_display_open(const char *id, Error **errp)
> >      QemuOpts *opts = qemu_opts_find(&qemu_vnc_opts, id);
> >      g_autoptr(SocketAddressList) saddr_list = NULL;
> >      g_autoptr(SocketAddressList) wsaddr_list = NULL;
> > -    const char *share, *device_id;
> > +    const char *share, *device_id, *name;
> >      QemuConsole *con;
> >      bool password = false;
> >      bool reverse = false;
> > @@ -4217,6 +4220,9 @@ void vnc_display_open(const char *id, Error **errp)
> >      }
> >      qkbd_state_set_delay(vd->kbd, key_delay_ms);
> >
> > +    name = qemu_opt_get(opts, "name");
> > +    qemu_console_set_name(vd->dcl.con, name);
> 
> Why not expose a "head_name" property in QemuGraphicConsole?

QemuGraphicConsole isn't mapped to any CLI though, is it ?

In QAPI we have DisplayOptions union  for all the local displays,
and as a user I think I'd expect 'name' to be settable from
those.

For VNC/SPICE, we have not mapped to QAPI, but they do have their
own CLI options we can expose.

For runtime setting, we have a QMP  "display-update" command, that
currently just lets you change VNC listening address, but was intended
to allow for any runtime display changes.

> This way it should be possible to set the name with QMP qom-set.

qom-set isn't a particularly nice interface, as things you can set
from that are not introspectable and have no type information that
can be queried.

With regards,
Daniel
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