[PATCH v3 5/5] docs: add basic CI documentation

[Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>]

Include info how to get access/enable hardware runners and how to select
individual jobs.

Signed-off-by: Marek Marczykowski-Górecki <marmarek@xxxxxxxxxxxxxxxxxxxxxx>
---
new in v3
Definitely there can be more content here, but lets start somewhere.
---
 docs/index.rst   |  1 +
 docs/misc/ci.rst | 35 +++++++++++++++++++++++++++++++++++
 2 files changed, 36 insertions(+)
 create mode 100644 docs/misc/ci.rst

diff --git a/docs/index.rst b/docs/index.rst
index 1bb8d02ea357..bd87d736b9c3 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -51,6 +51,7 @@ kind of development environment.
    :maxdepth: 2
 
    hypervisor-guide/index
+   misc/ci
 
 
 Unsorted documents
diff --git a/docs/misc/ci.rst b/docs/misc/ci.rst
new file mode 100644
index 000000000000..2803574fa2c0
--- /dev/null
+++ b/docs/misc/ci.rst
@@ -0,0 +1,35 @@
+.. SPDX-License-Identifier: CC-BY-4.0
+
+Continuous Integration
+======================
+
+Xen Project uses Gitlab-CI for automated testing. Test pipelines for official
+staging branches are at
+`<https://gitlab.com/xen-project/hardware/xen/-/pipelines>`_. Developers can
+schedule test pipelines in their repositories under
+`<https://gitlab.com/xen-project/people/>`_.
+
+Hardware runners
+****************
+
+Some of the tests are using dedicated hardware runners. Those are not 
available freely, but the access is granted to individual developers. To get 
access to them, ask on the ``#XenDevel:matrix.org`` Matrix channel.
+After getting access to relevant runners, few extra changes are necessary in 
settings of the relevant "xen" gitlab project (under your 
`<https://gitlab.com/xen-project/people/>`_ namespace):
+
+1. Go to Settings -> CI/CD, expand the "Runners" section and enable relevant 
runners for your project.
+2. Expand "Variables" section and add ``QUBES_JOBS=true`` variable for Qubes 
runners, and ``XILINX_JOBS=true`` for Xilinx runners.
+3. Go to Settings -> Repository, expand "Branch rules" section and add a rule 
for protected branches - only those branches will get tests on the hardware 
runners. It's okay to use a pattern for branch name, and it's okay to allow 
force push.
+
+Selecting individual tests
+**************************
+
+Normally, all build and test jobs are scheduled in a pipeline. When working on 
a specific patches, it is sometimes useful to run only jobs relevant for the 
current work - both to save time and to save CI resources. This can be done by 
seeting ``SELECTED_JOBS_ONLY`` variable when starting the pipeline. The 
variable holds a regular expression, enclosed with ``/`` that matches jobs to 
be included. The variable can be set via the gitlab.com web UI or directly when 
pushing changes to gitlab::
+
+   git push -o ci.variable=SELECTED_JOBS_ONLY="/job1|job2/"
+
+Note if a test job requires some build job, both need to be included in the 
regex. For example, ``adl-smoke-x86-64-gcc-debug`` requires 
``alpine-3.18-gcc-debug``, so to run just this test the command will look like 
this::
+
+   git push -o 
ci.variable=SELECTED_JOBS_ONLY="/adl-smoke-x86-64-gcc-debug|alpine-3.18-gcc-debug/"
+
+More details at 
`<https://docs.gitlab.co.jp/ee/user/project/push_options.html>`_.
+
+Alternatively, irrelevant jobs can be removed from respective yaml files in 
``automation/gitlab-ci`` by adding temporary commit on top of the branch.
-- 
git-series 0.9.1