[pve-devel] [PATCH docs] fix #4068: document fw_cfg parameter

[Leo Nunner <l.nunner@proxmox.com>]

Signed-off-by: Leo Nunner <l.nunner@proxmox.com>
---
 qm.adoc | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/qm.adoc b/qm.adoc
index bd535a2..0c587ad 100644
--- a/qm.adoc
+++ b/qm.adoc
@@ -1139,6 +1139,24 @@ http://localhost:9843 in a browser in the guest.
 
 It can help to restart the SPICE session.
 
+[[qm_fw_cfg]]
+QEMU Firmware Configuration
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+QEMU allows passing values to the guest via the 'fw_cfg' parameter. Settings
+are defined on a key/value basis, where the key follows a directory-like structure:
+
+----
+opt/com.proxmox/test1=local:snippets/config.txt
+opt/com.proxmox/test2=foobar
+----
+
+These settings can be edited in the GUI via 'Options' -> 'QEMU Firmware Configuration'.
+User-supplied keys *must* be prefixed with `opt/` and are recommended to start with a
+reverse fully qualified domain name. `opt/ovmf/` and `opt/org.qemu/` are reserved for
+internal use by QEMU and should not be set. Setting a value in the format
+`storage:snippets/file` causes the contents of the file to be included for the key.
+
 [[qm_migration]]
 Migration
 ---------
-- 
2.30.2