[PATCH v4 22/22] doc: bootefi: note two-phase runtime variables selftest

The bootefi documentation did not describe how to run the
runtime-variable selftest, so users had no guidance on its reboot
requirements or on which flow applies to their configuration.

Document the runtime-variable selftest flow in bootefi.rst. Describe
the non-volatile path, note the single-run
CONFIG_EFI_RT_VOLATILE_STORE=y case, and show how to select the
runtime-variable selftest with efi_selftest.

Reviewed-by: Simon Glass <[email protected]>
Signed-off-by: Harsimran Singh Tungal <[email protected]>
---
 doc/usage/cmd/bootefi.rst | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/doc/usage/cmd/bootefi.rst b/doc/usage/cmd/bootefi.rst
index 7c5448586b7..0a7800b93ce 100644
--- a/doc/usage/cmd/bootefi.rst
+++ b/doc/usage/cmd/bootefi.rst
@@ -160,6 +160,37 @@ environment variable to match one of the listed identifiers
 Some of the tests execute the ExitBootServices() UEFI boot service and will not
 return to the command line but require a board reset.
 
+When CONFIG_EFI_RT_VOLATILE_STORE is enabled, the test
+*variables at runtime* completes within one *bootefi selftest* run, so
+it does not depend on preserving state across multiple runs. It still
+executes ExitBootServices(), so a board reset is required afterwards
+before returning to the command line.
+
+::
+
+    => setenv efi_selftest 'variables at runtime'
+    => bootefi selftest
+
+When CONFIG_EFI_RT_VOLATILE_STORE is not enabled, the runtime-variable
+flow is split into *variables at runtime setup* and
+*variables at runtime verify*. Run the setup test once to create the
+runtime-accessible variable in non-volatile storage, reboot, then run
+the verify test to validate, append, and delete that variable.
+Both phases are on-request tests, so they only run when selected by
+``efi_selftest``.
+
+::
+
+    => setenv efi_selftest 'variables at runtime setup'
+    => bootefi selftest
+
+After reboot:
+
+::
+
+    => setenv efi_selftest 'variables at runtime verify'
+    => bootefi selftest
+
 Configuration
 -------------
 
-- 
2.34.1