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author | Thomas Huth <thuth@redhat.com> | 2020-07-09 18:00:39 +0200 |
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committer | Thomas Huth <thuth@redhat.com> | 2020-07-13 11:40:52 +0200 |
commit | 2a84f48c2b387877422ee85f6425d2c1b25bace0 (patch) | |
tree | dbadbeef3df6489d89f05e7252216053e43f2624 | |
parent | c02b2eac55ef72dd17b2ea8408c312d83f9e0482 (diff) | |
download | qemu-2a84f48c2b387877422ee85f6425d2c1b25bace0.zip qemu-2a84f48c2b387877422ee85f6425d2c1b25bace0.tar.gz qemu-2a84f48c2b387877422ee85f6425d2c1b25bace0.tar.bz2 |
docs/system/s390x: Improve the 3270 documentation
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).
While at it, I also shortened the lines of the first example a little bit.
Otherwise they showed up with a horizontal scrollbar in my Firefox browser.
Message-Id: <20200713075112.442-1-thuth@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
-rw-r--r-- | docs/system/s390x/3270.rst | 43 |
1 files changed, 37 insertions, 6 deletions
diff --git a/docs/system/s390x/3270.rst b/docs/system/s390x/3270.rst index 1774cdc..0554a70 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 Linux 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 * Start the guest. In the guest, use ``chccwdev -e 0.0.000a`` to enable the device. @@ -29,4 +39,25 @@ Example configuration systemctl start serial-getty@3270-tty1.service -This should get you an addtional tty for logging into the guest. + This should get you an additional tty for logging into the guest. + +* If you want to use the 3270 device as the Linux 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 very basic. In particular: + +* Only one 3270 device is supported. + +* It has only been tested with Linux guests and the x3270 emulator. + +* TLS/SSL is not supported. + +* Resizing on reattach is not supported. + +* Multiple commands in one inbound buffer (for example, when the reset key + is pressed while the network is slow) are not supported. |