[libvirt] [PATCH 3/6] docs: Add docs and rng schema for new XML tag sgio

[Osier Yang]

This introduces new XML tag "sgio" for disk, its valid values
are "filtered" and "unfiltered", setting it as "filtered" will
set the disk's unpriv_sgio to 0, and "unfiltered" to set it
as 1, which allows the unprivileged SG_IO commands.
---
 docs/formatdomain.html.in     |   14 ++++++++++-
 docs/schemas/domaincommon.rng |   54 +++++++++++++++++++++++++++-------------
 2 files changed, 49 insertions(+), 19 deletions(-)

diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in
index 8d9ab9e..ac55845 100644
--- a/docs/formatdomain.html.in
+++ b/docs/formatdomain.html.in
@@ -1395,7 +1395,19 @@
         rawio='yes', rawio capability will be enabled for all disks in
         the domain (because, in the case of QEMU, this capability can
         only be set on a per-process basis). This attribute is only
-        valid when device is "lun".
+        valid when device is "lun". NB, <code>rawio</code> intends to
+        confine the capability per-device, however, current QEMU
+        implementation gives the domain process broader capability
+        than that (per-process basis, affects all the domain disks).
+        To confine the capability as much as possible for QEMU driver
+        as this stage, <code>sgio</code> is recommended, it's more
+        secure than <code>rawio</code>.
+        The optional <code>sgio</code> attribute indicates whether the
+        kernel will filter unprivileged SG_IO commands for the disk,
+        valid settings are "filtered" or "unfiltered". Defaults to
+        "filtered". Same with <code>rawio</code>, <code>sgio</code>
+        is only valid for device 'lun'.
+        <span class="since">since 1.0.2</span>
         The optional <code>snapshot</code> attribute indicates the default
         behavior of the disk during disk snapshots: "internal"
         requires a file format such as qcow2 that can store both the
diff --git a/docs/schemas/domaincommon.rng b/docs/schemas/domaincommon.rng
index 0529d62..7a97781 100644
--- a/docs/schemas/domaincommon.rng
+++ b/docs/schemas/domaincommon.rng
@@ -971,24 +971,42 @@
     -->
   <define name="disk">
     <element name="disk">
-      <optional>
-        <attribute name="device">
-          <choice>
-            <value>floppy</value>
-            <value>disk</value>
-            <value>cdrom</value>
-            <value>lun</value>
-          </choice>
-        </attribute>
-      </optional>
-      <optional>
-        <attribute name="rawio">
-          <choice>
-            <value>yes</value>
-            <value>no</value>
-          </choice>
-        </attribute>
-      </optional>
+      <choice>
+        <group>
+          <optional>
+            <attribute name="device">
+              <choice>
+                <value>floppy</value>
+                <value>disk</value>
+                <value>cdrom</value>
+              </choice>
+            </attribute>
+          </optional>
+        </group>
+        <group>
+          <attribute name="device">
+            <choice>
+              <value>lun</value>
+            </choice>
+          </attribute>
+          <optional>
+            <attribute name="rawio">
+              <choice>
+                <value>yes</value>
+                <value>no</value>
+              </choice>
+            </attribute>
+          </optional>
+          <optional>
+            <attribute name="sgio">
+              <choice>
+                <value>filtered</value>
+                <value>unfiltered</value>
+              </choice>
+            </attribute>
+          </optional>
+        </group>
+      </choice>
       <optional>
         <ref name="snapshot"/>
       </optional>
-- 
1.7.7.6