[PATCH] docs: specify numerical values of Xenstore commands

[Juergen Gross <jgross@xxxxxxxx>]

In docs/misc/xenstore.txt all Xenstore commands are specified, but
the specifications lack the numerical values of the commands.

Add a table with all commands, their values, and a potential remark
(e.g. whether the command is optional).

Reported-by: Jan Beulich <jbeulich@xxxxxxxx>
Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
---
 docs/misc/xenstore.txt | 59 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 59 insertions(+)

diff --git a/docs/misc/xenstore.txt b/docs/misc/xenstore.txt
index 7e1f031520..76001c6ee6 100644
--- a/docs/misc/xenstore.txt
+++ b/docs/misc/xenstore.txt
@@ -86,6 +86,65 @@ parts of xenstore inaccessible to some clients.  In any case 
passing
 bulk data through xenstore is not recommended as the performance
 properties are poor.
 
+---------- Defined Xenstore message types ----------
+
+Below is a table with all defined Xenstore message types (type name
+and its associated numerical value).
+
+Some types are optional to be supported by a specific Xenstore
+implementation.  If an optional type is not supported by a Xenstore
+implementation, Xen tools will continue to work, maybe with slightly
+reduced functionality.  A mandatory type not being supported will
+result in severely reduced functionality, like inability to create
+domains.  In case a type is optional, this is stated in the table with
+the lost functionality in case Xenstore doesn't support that type.
+
+XS_CONTROL             0       optional
+       If not supported, xenstore-control command will not work.
+       XS_DEBUG is a deprecated alias of XS_CONTROL.
+XS_DIRECTORY           1
+XS_READ                        2
+XS_GET_PERMS           3
+XS_WATCH               4
+XS_UNWATCH             5
+XS_TRANSACTION_START   6
+XS_TRANSACTION_END     7
+XS_INTRODUCE           8
+XS_RELEASE             9
+XS_GET_DOMAIN_PATH     10
+XS_WRITE               11
+XS_MKDIR               12
+XS_RM                  13
+XS_SET_PERMS           14
+XS_WATCH_EVENT         15
+       Not valid in client sent messages.
+       Only valid in Xenstore replies.
+XS_ERROR               16
+       Not valid in client sent messages.
+       Only valid in Xenstore replies.
+XS_IS_DOMAIN_INTRODUCED        17
+XS_RESUME              18
+XS_SET_TARGET          19
+XS_RESTRICT            20      no longer supported
+       XS_RESTRICT has been removed, the type value 20 is invalid.
+XS_RESET_WATCHES       21
+XS_DIRECTORY_PART      22      optional
+       If not supported, the output of xenstore-ls might be incomplete
+       with moŕe than ca. 1000 domains active.
+XS_GET_FEATURE         23      optional
+XS_SET_FEATURE         24      optional
+       XS_GET_FEATURE and XS_SET_FEATURE must either be both supported
+       or both unsupported.
+       If unsupported, setting availability of Xenstore features per
+       domain is not possible.
+XS_GET_QUOTA           25      optional
+XS_SET_QUOTA           26      optional
+       XS_GET_QUOTA and XS_SET_QUOTA must either be both supported
+       or both unsupported.
+       If unsupported, setting of Xenstore quota per domain is not
+       possible.
+XS_INVALID             65535
+       Guaranteed invalid type (never supported).
 
 ---------- Xenstore protocol details - introduction ----------
 
-- 
2.43.0