diff --git a/OvmfPkg/PlatformPei/MemDetect.c b/OvmfPkg/PlatformPei/MemDetect.c
index 2c2c4641ec..d736b85e0d 100644
--- a/OvmfPkg/PlatformPei/MemDetect.c
+++ b/OvmfPkg/PlatformPei/MemDetect.c
@@ -135,6 +135,10 @@ QemuUc32BaseInitialization (
   UINT32 LowerMemorySize;
   UINT32 Uc32Size;
 
+  if (mHostBridgeDevId == 0xffff /* microvm */) {
+    return;
+  }
+
   if (mHostBridgeDevId == INTEL_Q35_MCH_DEVICE_ID) {
     //
     // On q35, the 32-bit area that we'll mark as UC, through variable MTRRs,