diff --git a/src/emu/system.c b/src/emu/system.c
index 07914a4..02c7df0 100644
--- a/src/emu/system.c
+++ b/src/emu/system.c
@@ -183,6 +183,14 @@ create_system(struct system *sys, struct trace *trace)
 		stream_data_set(s, lpt);
 	}
 
+	/* Ensure all looms have at least one CPU */
+	for (struct loom *l = sys->looms; l; l = l->next) {
+		if (l->ncpus == 0) {
+			err("loom %s has no physical CPUs", l->id);
+			return -1;
+		}
+	}
+
 	return 0;
 }
 
diff --git a/test/emu/ovni/CMakeLists.txt b/test/emu/ovni/CMakeLists.txt
index 323d209..053755a 100644
--- a/test/emu/ovni/CMakeLists.txt
+++ b/test/emu/ovni/CMakeLists.txt
@@ -1,4 +1,4 @@
-# Copyright (c) 2022 Barcelona Supercomputing Center (BSC)
+# Copyright (c) 2022-2023 Barcelona Supercomputing Center (BSC)
 # SPDX-License-Identifier: GPL-3.0-or-later 
 
 # Only run performance sensitive tests on Release builds
@@ -16,3 +16,4 @@ ovni_test(mp-simple.c MP)
 ovni_test(version-good.c)
 ovni_test(version-bad.c SHOULD_FAIL REGEX "version mismatch")
 ovni_test(clockgate.c MP SHOULD_FAIL REGEX "detected large clock gate")
+ovni_test(no-cpus.c SHOULD_FAIL REGEX "loom .* has no physical CPUs")
diff --git a/test/emu/ovni/no-cpus.c b/test/emu/ovni/no-cpus.c
new file mode 100644
index 0000000..1d446a2
--- /dev/null
+++ b/test/emu/ovni/no-cpus.c
@@ -0,0 +1,13 @@
+/* Copyright (c) 2023 Barcelona Supercomputing Center (BSC)
+ * SPDX-License-Identifier: GPL-3.0-or-later */
+
+#include "instr_ovni.h"
+
+int
+main(void)
+{
+	instr_start(0, 0);
+	instr_end();
+
+	return 0;
+}