tests: Get host_data based on libvirt version

Decode host_data if needed. Based on host libvirt
version, platform is setting the host_data as
b64 encoded or plain text string.

Signed-off-by: Smit Gardhariya <[email protected]>

microsoft/testsuites/cvm/cvm_attestation.py

@@ -1,5 +1,7 @@
 # Copyright (c) Microsoft Corporation.
 # Licensed under the MIT license.
+import base64
+import binascii
 from pathlib import Path
 from typing import Any, Dict
 
@@ -124,7 +126,7 @@ def verify_nested_cvm_attestation_report(
         from lisa.sut_orchestrator.libvirt.context import get_node_context
 
         node_context = get_node_context(node)
-        host_data = node_context.host_data
+        host_data = self._get_host_data(node_context.host_data)
         if not host_data:
             raise SkippedException("host_data is empty")
         node.tools[NestedCVMAttestationTests].run_cvm_attestation(
@@ -133,3 +135,16 @@ def verify_nested_cvm_attestation_report(
             log_path,
             host_data,
         )
+
+    def _get_host_data(self, host_data: str) -> str:
+        # Based on libvirt version our libvirt platform will set
+        # either plain text or b64 encoded string as host data.
+        # We need to decode it as this test would get host_data
+        # from attestation tool as plain text
+        # or
+        # Return original data if decoding fails considering
+        # this is non-encoded string
+        try:
+            return base64.b64decode(host_data).decode("utf-8")
+        except (binascii.Error, UnicodeDecodeError):
+            return host_data