[RFC v3 0/2] Update index after allocating port for isa-serial device

[Divya Garg]

Issue
-----
-----
The port being provided in the xml file of the domain is not getting reflected
in the generated qemu command

For instance, on adding the serial device:

<serial>
<target type='serial' port='3'/>
</serial>

Generated qemu command will look like :
/usr/libexec/qemu-kvm ...\
    -device isa-serial,chardev=charserial0,id=serial0

Actually it should be :
/usr/libexec/qemu-kvm ...\
    -device isa-serial,chardev=charserial0,id=serial0,index=3

So that qemu understands which port needs to be allocated for the device.

Patch
-----
-----
Out already for the correction :
https://listman.redhat.com/archives/libvir-list/2018-April/msg02302.html

This patch was not followed up. According to me there can be multiple reasons.
I have mentioned them below:
---------------------------------------------------------------------------
---------------------------------------------------------------------------
Index : specifies the index number of a connector port. If not specified, the
index is automatically incremented. This logic exists both on qemu as well as
libvirt.
https://github.com/qemu/qemu/blob/master/hw/char/serial-isa.c#L62

Issue 1:
-------
If we want two isa-serial devices and for the first one if we mention the port
to be 3, then for the next device it automatically assigns the port number 4,
which will throw the following error :
error: internal error: process exited while connecting to monitor:
2021-11-12T11:05:31.169987Z qemu-kvm: -device
isa-serial,chardev=charserial2,id=serial2,index=5: Max. supported number of ISA
serial ports is 4.

But we are left with 3 ports (0,1,2) which are unused. So ideally we should
have used them.

Issue 2:
-------
It is possible that two devices get the same port address which might lead to a
lot of ambiguity. Example: we want two devices and for the second one we
provide the index 0. Then from default logic the first device will be allotted
port 0 and the second device will overwrite it and get port 0.

This patch-set tends to solve the problem.
It contains two commits that deals with the issue in following order :
    - check the input provided, and make sure to correctly assign ports
    - provide the corrected port values to qemu

Divya Garg (2):
  Add the port allocation logic for isa-serial devices.
  qemu: add index for isa-serial device using target.port

 src/conf/domain_conf.c                        | 61 ++++++++++++++++---
 src/conf/domain_conf.h                        |  6 ++
 src/qemu/qemu_command.c                       | 22 +++++--
 ...g-console-compat-2-live+console-virtio.xml |  4 +-
 .../qemuhotplug-console-compat-2-live.xml     |  4 +-
 tests/qemuxml2argvdata/bios.args              |  2 +-
 .../qemuxml2argvdata/console-compat-auto.args |  2 +-
 .../console-compat-auto.x86_64-latest.args    |  2 +-
 .../console-compat-chardev.args               |  2 +-
 .../console-compat-chardev.x86_64-latest.args |  2 +-
 tests/qemuxml2argvdata/console-compat.args    |  2 +-
 .../console-compat.x86_64-latest.args         |  2 +-
 .../qemuxml2argvdata/console-virtio-many.args |  2 +-
 tests/qemuxml2argvdata/controller-order.args  |  2 +-
 .../name-escape.x86_64-2.11.0.args            |  4 +-
 .../name-escape.x86_64-latest.args            |  4 +-
 .../q35-virt-manager-basic.args               |  2 +-
 .../serial-dev-chardev-iobase.args            |  2 +-
 ...rial-dev-chardev-iobase.x86_64-latest.args |  2 +-
 .../qemuxml2argvdata/serial-dev-chardev.args  |  2 +-
 .../serial-dev-chardev.x86_64-latest.args     |  2 +-
 .../qemuxml2argvdata/serial-file-chardev.args |  2 +-
 .../serial-file-chardev.x86_64-latest.args    |  2 +-
 tests/qemuxml2argvdata/serial-file-log.args   |  2 +-
 .../serial-file-log.x86_64-latest.args        |  2 +-
 .../qemuxml2argvdata/serial-many-chardev.args |  4 +-
 .../serial-many-chardev.x86_64-latest.args    |  4 +-
 .../qemuxml2argvdata/serial-pty-chardev.args  |  2 +-
 .../serial-pty-chardev.x86_64-latest.args     |  2 +-
 tests/qemuxml2argvdata/serial-spiceport.args  |  2 +-
 .../serial-spiceport.x86_64-latest.args       |  2 +-
 .../qemuxml2argvdata/serial-tcp-chardev.args  |  2 +-
 .../serial-tcp-chardev.x86_64-latest.args     |  2 +-
 .../serial-tcp-telnet-chardev.args            |  2 +-
 ...rial-tcp-telnet-chardev.x86_64-latest.args |  2 +-
 .../serial-tcp-tlsx509-chardev-notls.args     |  4 +-
 ...p-tlsx509-chardev-notls.x86_64-latest.args |  4 +-
 .../serial-tcp-tlsx509-chardev-notls.xml      |  2 +-
 .../serial-tcp-tlsx509-chardev-verify.args    |  4 +-
 ...-tlsx509-chardev-verify.x86_64-latest.args |  4 +-
 .../serial-tcp-tlsx509-chardev-verify.xml     |  2 +-
 .../serial-tcp-tlsx509-chardev.args           |  4 +-
 ...ial-tcp-tlsx509-chardev.x86_64-latest.args |  4 +-
 .../serial-tcp-tlsx509-chardev.xml            |  2 +-
 .../serial-tcp-tlsx509-secret-chardev.args    |  4 +-
 ...-tlsx509-secret-chardev.x86_64-latest.args |  4 +-
 .../serial-tcp-tlsx509-secret-chardev.xml     |  2 +-
 .../qemuxml2argvdata/serial-udp-chardev.args  |  4 +-
 .../serial-udp-chardev.x86_64-latest.args     |  4 +-
 .../qemuxml2argvdata/serial-unix-chardev.args |  4 +-
 .../serial-unix-chardev.x86_64-latest.args    |  4 +-
 tests/qemuxml2argvdata/serial-vc-chardev.args |  2 +-
 .../serial-vc-chardev.x86_64-latest.args      |  2 +-
 tests/qemuxml2argvdata/user-aliases.args      |  4 +-
 .../virtio-9p-createmode.x86_64-latest.args   |  2 +-
 .../virtio-9p-multidevs.x86_64-latest.args    |  2 +-
 .../x86_64-pc-graphics.x86_64-latest.args     |  2 +-
 .../x86_64-pc-headless.x86_64-latest.args     |  2 +-
 .../x86_64-q35-graphics.x86_64-latest.args    |  2 +-
 .../x86_64-q35-headless.x86_64-latest.args    |  2 +-
 .../serial-tcp-tlsx509-chardev.xml            |  2 +-
 61 files changed, 153 insertions(+), 90 deletions(-)

-- 
2.25.1