docs: kbase: Add a section explaining how to verify SEV from the guest

Commit 50dfabbb forgot to add this important bit on how to check that
all the changes to the XML actually worked.
Signed-off-by: NErik Skultety <eskultet@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>

docs/kbase/launch_security_sev.html.in

@@ -349,6 +349,18 @@ EOF</pre>
   ...
 &lt;/domain&gt;</pre>
 
+    <h2><a id="Guest">Checking SEV from within the guest</a></h2>
+    <p>
+        After making the necessary adjustments discussed in
+        <a href="#Configuration">Configuration</a>, the VM should now boot
+        successfully with SEV enabled. You can then verify that the guest has
+        SEV enabled by running:
+    </p>
+
+    <pre>
+# dmesg | grep -i sev
+AMD Secure Encrypted Virtualization (SEV) active</pre>
+
     <h2><a id="Limitations">Limitations</a></h2>
     <p>
         Currently, the boot disk cannot be of type virtio-blk, instead, virtio-scsi