diff --git a/src/api.c b/src/api.c
index 6da649c..f6895ca 100644
--- a/src/api.c
+++ b/src/api.c
@@ -146,6 +146,12 @@
 		goto exit;
 	}
 
+	/* Fail if the same page is used for the send and receive pages. */
+	if (pa_addr(pa_send_begin) == pa_addr(pa_recv_begin)) {
+		ret = -1;
+		goto exit;
+	}
+
 	pa_send_end = pa_add(pa_send_begin, PAGE_SIZE);
 	pa_recv_end = pa_add(pa_recv_begin, PAGE_SIZE);
 
diff --git a/test/vm/primary_with_secondary/primary.c b/test/vm/primary_with_secondary/primary.c
index 22b84aa..bcbb592 100644
--- a/test/vm/primary_with_secondary/primary.c
+++ b/test/vm/primary_with_secondary/primary.c
@@ -1,9 +1,17 @@
+#include <assert.h>
+#include <stdalign.h>
 #include <stdint.h>
 
 #include "../hf_test.h"
+#include "mm.h"
 #include "vmapi/hf/call.h"
 
-uint8_t kstack[4096] __attribute__((aligned(4096)));
+alignas(4096) uint8_t kstack[4096];
+
+alignas(PAGE_SIZE) uint8_t send_page[PAGE_SIZE];
+alignas(PAGE_SIZE) uint8_t recv_page[PAGE_SIZE];
+static_assert(sizeof(send_page) == PAGE_SIZE, "Send page is not a page.");
+static_assert(sizeof(recv_page) == PAGE_SIZE, "Recv page is not a page.");
 
 TEST(vm_get_count)
 {
@@ -20,9 +28,54 @@
 	EXPECT_EQ(hf_vcpu_get_count(0xffffffff), -1);
 }
 
+TEST(vm_configure_fails_with_unaligned_pointer)
+{
+	uint8_t maybe_aligned[2];
+	hf_ipaddr_t unaligned_addr = (hf_ipaddr_t)&maybe_aligned[1];
+	hf_ipaddr_t aligned_addr = (hf_ipaddr_t)&send_page;
+
+	/* Check the the address is unaligned. */
+	ASSERT_EQ(unaligned_addr & 1, 1);
+
+	EXPECT_EQ(hf_vm_configure(aligned_addr, unaligned_addr), -1);
+	EXPECT_EQ(hf_vm_configure(unaligned_addr, aligned_addr), -1);
+	EXPECT_EQ(hf_vm_configure(unaligned_addr, unaligned_addr), -1);
+}
+
+TEST(vm_configure_fails_with_same_page)
+{
+	EXPECT_EQ(
+		hf_vm_configure((hf_ipaddr_t)send_page, (hf_ipaddr_t)send_page),
+		-1);
+	EXPECT_EQ(
+		hf_vm_configure((hf_ipaddr_t)recv_page, (hf_ipaddr_t)recv_page),
+		-1);
+}
+
+TEST(vm_configure)
+{
+	EXPECT_EQ(
+		hf_vm_configure((hf_ipaddr_t)send_page, (hf_ipaddr_t)recv_page),
+		0);
+}
+
+TEST(vm_configure_fails_if_already_succeeded)
+{
+	EXPECT_EQ(
+		hf_vm_configure((hf_ipaddr_t)send_page, (hf_ipaddr_t)recv_page),
+		-1);
+}
+
 void kmain(void)
 {
 	RUN_TEST(vm_get_count);
 	RUN_TEST(vcpu_get_count_when_no_secondary_vm);
 	RUN_TEST(vcpu_get_count_for_large_invalid_vm_index);
+
+	/* TODO: the order matters as the configuration can only be set once.
+	 * We'll need to work out how to deal with this better in the tests. */
+	RUN_TEST(vm_configure_fails_with_unaligned_pointer);
+	RUN_TEST(vm_configure_fails_with_same_page);
+	RUN_TEST(vm_configure);
+	RUN_TEST(vm_configure_fails_if_already_succeeded);
 }