Explain in greater detail what 'check-block' will run for each format,
and also document the new format specific targets.

Reviewed-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 docs/devel/testing/main.rst    | 25 ++++++++++++++++++++++---
 tests/qemu-iotests/meson.build |  2 ++
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/docs/devel/testing/main.rst b/docs/devel/testing/main.rst
index 0662766b5c..dc4f7202a5 100644
--- a/docs/devel/testing/main.rst
+++ b/docs/devel/testing/main.rst
@@ -221,9 +221,28 @@ same commit that alters the generator code.
 check-block
 ~~~~~~~~~~~
 
-``make check-block`` runs a subset of the block layer iotests (the tests that
-are in the "auto" group).
-See the "QEMU iotests" section below for more information.
+There are a variety of ways to exercise the block layer I/O tests
+via make targets.
+
+A default ``make check`` or ``make check-block`` command will exercise
+the ``qcow2`` format, using the tests tagged into the ``auto`` group
+only.
+
+These targets accept the ``SPEED`` variable to augment the set of tests
+to run. A slightly more comprehensive test plan can be run by defining
+``SPEED=slow``, which enables all tests for the ``qcow2`` and ``raw``
+formats. The most comprehensive test plan can be run by defining
+``SPEED=thorough``, which enables all available tests for the formats
+``parallels``, ``qcow2``, ``qed``, ``raw``, ``vdi``, ``vhdx``,
+``vmdk``, and ``vpc``.
+
+Each of formats also has its own dedicated make target, named
+``make check-block-$FORMAT`` which will run all available tests for
+the designated format and does not require the ``SPEED`` variable
+to be set.
+
+See the "QEMU iotests" section below for more information on the
+block I/O test framework that is leveraged by these ``make`` targets.
 
 .. _qemu-iotests:
 
diff --git a/tests/qemu-iotests/meson.build b/tests/qemu-iotests/meson.build
index 16a5e39476..66b09d6b97 100644
--- a/tests/qemu-iotests/meson.build
+++ b/tests/qemu-iotests/meson.build
@@ -10,6 +10,8 @@ endif
 
 qemu_iotests_binaries = [qemu_img, qemu_io, qemu_nbd, qsd]
 qemu_iotests_env = {'PYTHON': python.full_path()}
+# If altering this definition, also update docs/devel/testing/main.rst
+# section on 'check-block' targets to reflect the changes
 qemu_iotests_formats = {
   'qcow2': 'quick',
   'raw': 'slow',
-- 
2.52.0