On Thu, 9 Jul 2020 18:04:39 +0200 Thomas Huth <[email protected]> wrote:
> There is some additional information about the 3270 support in our > Wiki at https://wiki.qemu.org/Features/3270 - so let's include this > information into the main documentation now to have one single > source of information (the Wiki page could later be removed). No objection; but what should our general policy with regard to wiki pages vs. documentation be? The 3270 support is pretty much static, but e.g. for vfio-ccw, we use the wiki page as a place where we track things that should be worked on etc. (Related: What is the scope of our QEMU documentation? Is a libvirt XML snippet on topic? Kernel configuration options (as in here)?) > > Signed-off-by: Thomas Huth <[email protected]> > --- > docs/system/s390x/3270.rst | 43 ++++++++++++++++++++++++++++++++------ > 1 file changed, 37 insertions(+), 6 deletions(-) > > diff --git a/docs/system/s390x/3270.rst b/docs/system/s390x/3270.rst > index 1774cdcadf..80350264d7 100644 > --- a/docs/system/s390x/3270.rst > +++ b/docs/system/s390x/3270.rst > @@ -1,9 +1,15 @@ > 3270 devices > ============ > > -QEMU supports connecting an external 3270 terminal emulator (such as > -``x3270``) to make a single 3270 device available to a guest. Note that this > -supports basic features only. > +The 3270 is the classic 'green-screen' console of the mainframes (see the > +`IBM 3270 Wikipedia article <https://en.wikipedia.org/wiki/IBM_3270>`__). > + > +The 3270 data stream is not implemented within QEMU; the device only provides > +TN3270 (a telnet extension; see `RFC 854 > <https://tools.ietf.org/html/rfc854>`__ > +and `RFC 1576 <https://tools.ietf.org/html/rfc1576>`__) and leaves the heavy > +lifting to an external 3270 terminal emulator (such as ``x3270``) to make a > +single 3270 device available to a guest. Note that this supports basic > +features only. > > To provide a 3270 device to a guest, create a ``x-terminal3270`` linked to > a ``tn3270`` chardev. The guest will see a 3270 channel device. In order > @@ -12,10 +18,14 @@ to actually be able to use it, attach the ``x3270`` > emulator to the chardev. > Example configuration > --------------------- > > +* Make sure that 3270 support is enabled in the guest's kernel. You need > + ``CONFIG_TN3270`` and at least one of ``CONFIG_TN3270_TTY`` (for additional > + ttys) or ``CONFIG_TN3270_CONSOLE`` (for a 3270 console). > + > * Add a ``tn3270`` chardev and a ``x-terminal3270`` to the QEMU command > line:: > > - -chardev socket,id=char_0,host=0.0.0.0,port=2300,nowait,server,tn3270 > - -device x-terminal3270,chardev=char_0,devno=fe.0.000a,id=terminal_0 > + -chardev socket,id=ch0,host=0.0.0.0,port=2300,nowait,server,tn3270 > + -device x-terminal3270,chardev=ch0,devno=fe.0.000a,id=terminal0 Any reason why you changed this? > > * Start the guest. In the guest, use ``chccwdev -e 0.0.000a`` to enable > the device. > @@ -29,4 +39,25 @@ Example configuration > > systemctl start [email protected] > > -This should get you an addtional tty for logging into the guest. > + This should get you an addtional tty for logging into the guest. > + > +* If you want to use the 3270 device as the kernel console instead of an > + additional tty, you can also append ``conmode=3270 condev=000a`` to the > + guest's kernel command line. The kernel then should use the 3270 as > + console after the next boot. > + > +Restrictions > +------------ > + > +3270 support is still experimental. In particular: s/still experimental/very basic/ I don't think there's much progress on the horizon; let's not give people false hope :) > + > +* Only one 3270 device is supported. > + > +* It has only been tested with Linux guests and the x3270 emulator. > + > +* TLS/SSL is not yet supported. s/yet // > + > +* Resizing on reattach is not yet supported. s/yet // > + > +* Multiple commands in one inbound buffer (for example, when the reset key > + is pressed while the network is slow) are not yet supported. s/yet //
