libssh2_transport: Add docs to remote.html

Describe the existence of the transport driver and document the
configurable options.

docs/remote.html.in

@@ -136,8 +136,14 @@ Remote libvirt supports a range of transports:
       <dd> Unencrypted TCP/IP socket.  Not recommended for production
  use, this is normally disabled, but an administrator can enable
  it for testing or use over a trusted network.
- The standard port is 16509.
- </dd>
+ The standard port is 16509. </dd>
+      <dt> libssh2 </dt>
+      <dd> Transport over the SSH protocol using
+      <a href="http://libssh2.org/" title="libssh2 homepage">libssh2</a> instead
+of the OpenSSH binary. This transport uses the libvirt authentication callback for
+all ssh authentication calls and therefore supports keyboard-interactive authentication
+even with graphical management applications. As with the classic ssh transport
+netcat is required on the remote side.</dd>
     </dl>
     <p>
 The default transport, if no other is specified, is <code>tls</code>.
@@ -182,6 +188,9 @@ Connect to a libvirtd daemon offering unencrypted TCP/IP connections
 on localhost port 5000 and use the test driver with default
 settings.
 </li>
+<li><code>qemu+libssh2://user@host/system?known_hosts=/home/user/.ssh/known_hosts</code><br/> &#x2014;
+Connect to a remote host using a ssh connection with the libssh2 driver
+and use a different known_hosts file.</li>
     </ul>
     <h4>
       <a name="Remote_URI_parameters">Extra parameters</a>
@@ -237,7 +246,7 @@ Note that parameter values must be
         <td>
           <code>socket</code>
         </td>
-        <td> unix, ssh </td>
+        <td> unix, ssh, libssh2 </td>
         <td>
   The path to the Unix domain socket, which overrides the
   compiled-in default.  For ssh transport, this is passed to
@@ -252,7 +261,7 @@ Note that parameter values must be
         <td>
           <code>netcat</code>
         </td>
-        <td> ssh </td>
+        <td> ssh, libssh2 </td>
         <td>
   The name of the netcat command on the remote machine.
   The default is <code>nc</code>.  For ssh transport, libvirt
@@ -277,7 +286,7 @@ Note that parameter values must be
         <td>
           <code>keyfile</code>
         </td>
-        <td> ssh </td>
+        <td> ssh, libssh2 </td>
         <td>
   The name of the private key file to use to authentication to the remote
   machine.  If this option is not used the default keys are used.
@@ -341,6 +350,39 @@ Note that parameter values must be
         <td colspan="2"/>
         <td> Example: <code>pkipath=/tmp/pki/client</code> </td>
       </tr>
+      <tr>
+        <td>
+          <code>known_hosts</code>
+        </td>
+        <td> libssh2 </td>
+        <td>
+  Path to the known_hosts file to verify the host key agains. LibSSH2
+  supports OpenSSH-style known_hosts files, although it does not support
+  all key types, so using files created by the OpenSSH binary may result
+  into truncating the known_hosts file. It's recommended to use the default
+  known_hosts file is located in libvirt's client local configuration
+  directory e.g.: ~/.config/libvirt/known_hosts. Note: Use absolute paths.
+</td>
+      </tr>
+      <tr>
+        <td colspan="2"/>
+        <td> Example: <code>known_hosts=/root/.ssh/known_hosts</code> </td>
+      </tr>
+      <tr>
+        <td>
+          <code>sshauth</code>
+        </td>
+        <td> libssh2 </td>
+        <td>
+  A comma separated list of authentication methods to use. Default (is
+  "agent,privkey,keyboard-interactive". The order of the methods is perserved.
+  Some methods may require additional parameters.
+</td>
+      </tr>
+      <tr>
+        <td colspan="2"/>
+        <td> Example: <code>sshauth=privkey,agent</code> </td>
+      </tr>
     </table>
     <h3>
       <a name="Remote_certificates">Generating TLS certificates</a>