docs: clarify xenstore permission documentation

In docs/misc/xenstore.txt the description of the Xenstore node access
permissions is missing one important aspect, which can be found only
in the code or in the wiki [1]:

The first permission entry is defining the owner of the node via the
domid, and the access rights for all domains NOT having a dedicated
permission entry.

Make that aspect clear in the official documentation.

[1]: https://wiki.xenproject.org/wiki/XenBus#Permissions

Reported-by: Edwin Török <edwin.torok@cloud.com>
Signed-off-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Julien Grall <jgrall@amazon.com>

diff --git a/docs/misc/xenstore.txt b/docs/misc/xenstore.txt
index 8887e7df88140a7357f006bb8a37a5da9b2eaae6..d807ef0709b73ce5850576d4663d3e20043ccfaa 100644 (file)
--- a/docs/misc/xenstore.txt
+++ b/docs/misc/xenstore.txt
@@ -45,13 +45,16 @@ them to within 2048 bytes.  (See XENSTORE_*_PATH_MAX in xs_wire.h.)
 
 Each node has one or multiple permission entries.  Permissions are
 granted by domain-id, the first permission entry of each node specifies
-the owner of the node.  Permissions of a node can be changed by the
-owner of the node, the owner can only be modified by the control
-domain (usually domain id 0).  The owner always has the right to read
-and write the node, while other permissions can be setup to allow
-read and/or write access.  When a domain is being removed from Xenstore
-nodes owned by that domain will be removed together with all of those
-nodes' children.
+the owner of the node, who always has full access to the node (read and
+write permission).  The access rights of the first entry specify the
+allowed access for all domains not having a dedicated permission entry
+(the default is "n", removing access for all domains not explicitly
+added via additional permission entries).  Permissions of a node can be
+changed by the owner of the node, the owner can only be modified by the
+control domain (usually domain id 0).  Other permissions can be setup to
+allow read and/or write access for other domains.  When a domain is
+being removed from Xenstore nodes owned by that domain will be removed
+together with all of those nodes' children.
 
 
 Communication with xenstore is via either sockets, or event channel