diff --git a/tools/testing/selftests/kvm/lib/x86_64/tdx.h b/tools/testing/selftests/kvm/lib/x86_64/tdx.h
index c78dba1af14f..a28d15417d3e 100644
--- a/tools/testing/selftests/kvm/lib/x86_64/tdx.h
+++ b/tools/testing/selftests/kvm/lib/x86_64/tdx.h
@@ -56,6 +56,7 @@
 
 #define TDX_SUCCESS_PORT 0x30
 #define TDX_TEST_PORT 0x31
+#define TDX_DATA_REPORT_PORT 0x32
 #define TDX_IO_READ 0
 #define TDX_IO_WRITE 1
 
@@ -231,6 +232,18 @@ static inline void tdvmcall_fatal(uint64_t error_code)
 	tdcall(&regs);
 }
 
+/*
+ * Reports a 32 bit value from the guest to user space using a TDVM IO call.
+ * Data is reported on port TDX_DATA_REPORT_PORT.
+ */
+static inline uint64_t tdvm_report_to_user_space(uint32_t data)
+{
+	// Need to upcast data to match tdvmcall_io signature.
+	uint64_t data_64 = data;
+
+	return tdvmcall_io(TDX_DATA_REPORT_PORT, /*size=*/4, TDX_IO_WRITE, &data_64);
+}
+
 #define TDX_FUNCTION_SIZE(name) ((uint64_t)&__stop_sec_ ## name -\
 			   (uint64_t)&__start_sec_ ## name) \
 
diff --git a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
index a93629cfd13f..3f51f936ea5a 100644
--- a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
+++ b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
@@ -77,6 +77,27 @@ bool is_tdx_enabled(void)
 	return !!(kvm_check_cap(KVM_CAP_VM_TYPES) & BIT(KVM_X86_TDX_VM));
 }
 
+/*
+ * Find a specific CPUID entry.
+ */
+static struct kvm_cpuid_entry2 *
+find_cpuid_entry(struct tdx_cpuid_data cpuid_data, uint32_t function,
+		 uint32_t index)
+{
+	struct kvm_cpuid_entry2 *e;
+	int i;
+
+	for (i = 0; i < cpuid_data.cpuid.nent; i++) {
+		e = &cpuid_data.entries[i];
+
+		if (e->function == function &&
+		    (e->index == index ||
+		     !(e->flags & KVM_CPUID_FLAG_SIGNIFCANT_INDEX)))
+			return e;
+	}
+	return NULL;
+}
+
 /*
  * Do a dummy io exit to verify that the TD has been initialized correctly and
  * guest can run some code inside.
@@ -251,6 +272,116 @@ void verify_td_ioexit(void)
 	printf("\t ... PASSED\n");
 }
 
+/*
+ * Verifies CPUID functionality by reading CPUID values in guest. The guest
+ * will then send the values to userspace using an IO write to be checked
+ * against the expected values.
+ */
+TDX_GUEST_FUNCTION(guest_code_cpuid)
+{
+	uint64_t err;
+	uint32_t eax, ebx, edx, ecx;
+
+	// Read CPUID leaf 0x1.
+	cpuid(1, &eax, &ebx, &ecx, &edx);
+
+	err = tdvm_report_to_user_space(ebx);
+	if (err)
+		tdvmcall_fatal(err);
+
+	err = tdvm_report_to_user_space(ecx);
+	if (err)
+		tdvmcall_fatal(err);
+
+	tdvmcall_success();
+}
+
+void verify_td_cpuid(void)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+	uint32_t ebx, ecx;
+	struct kvm_cpuid_entry2 *cpuid_entry;
+	struct tdx_cpuid_data cpuid_data;
+	uint32_t guest_clflush_line_size;
+	uint32_t guest_max_addressable_ids, host_max_addressable_ids;
+	uint32_t guest_sse3_enabled;
+	uint32_t guest_fma_enabled;
+	uint32_t guest_initial_apic_id;
+	int ret;
+
+	printf("Verifying TD CPUID:\n");
+	/* Create a TD VM with no memory.*/
+	vm = vm_create_tdx();
+
+	/* Allocate TD guest memory and initialize the TD.*/
+	initialize_td(vm);
+
+	/* Initialize the TD vcpu and copy the test code to the guest memory.*/
+	vcpu = vm_vcpu_add_tdx(vm, 0);
+
+	/* Setup and initialize VM memory */
+	prepare_source_image(vm, guest_code_cpuid,
+			     TDX_FUNCTION_SIZE(guest_code_cpuid), 0);
+	finalize_td_memory(vm);
+
+	/* Wait for guest to report ebx value */
+	vcpu_run(vcpu);
+	CHECK_GUEST_FAILURE(vcpu);
+	CHECK_IO(vcpu, TDX_DATA_REPORT_PORT, 4, TDX_IO_WRITE);
+	ebx = *(uint32_t *)((void *)vcpu->run + vcpu->run->io.data_offset);
+
+	/* Wait for guest to report either ecx value or error */
+	vcpu_run(vcpu);
+	CHECK_GUEST_FAILURE(vcpu);
+	CHECK_IO(vcpu, TDX_DATA_REPORT_PORT, 4, TDX_IO_WRITE);
+	ecx = *(uint32_t *)((void *)vcpu->run + vcpu->run->io.data_offset);
+
+	/* Wait for guest to complete execution */
+	vcpu_run(vcpu);
+	CHECK_GUEST_FAILURE(vcpu);
+	CHECK_GUEST_COMPLETION(vcpu);
+
+	/* Verify the CPUID values we got from the guest. */
+	printf("\t ... Verifying CPUID values from guest\n");
+
+	/* Get KVM CPUIDs for reference */
+	memset(&cpuid_data, 0, sizeof(cpuid_data));
+	cpuid_data.cpuid.nent = KVM_MAX_CPUID_ENTRIES;
+	ret = ioctl(vm->kvm_fd, KVM_GET_SUPPORTED_CPUID, &cpuid_data);
+	TEST_ASSERT(!ret, "KVM_GET_SUPPORTED_CPUID failed\n");
+	cpuid_entry = find_cpuid_entry(cpuid_data, 1, 0);
+	TEST_ASSERT(cpuid_entry, "CPUID entry missing\n");
+
+	host_max_addressable_ids = (cpuid_entry->ebx >> 16) & 0xFF;
+
+	guest_sse3_enabled = ecx & 0x1;  // Native
+	guest_clflush_line_size = (ebx >> 8) & 0xFF;  // Fixed
+	guest_max_addressable_ids = (ebx >> 16) & 0xFF;  // As Configured
+	guest_fma_enabled = (ecx >> 12) & 0x1;  // As Configured (if Native)
+	guest_initial_apic_id = (ebx >> 24) & 0xFF;  // Calculated
+
+	ASSERT_EQ(guest_sse3_enabled, 1);
+	ASSERT_EQ(guest_clflush_line_size, 8);
+	ASSERT_EQ(guest_max_addressable_ids, host_max_addressable_ids);
+
+	/* TODO: This only tests the native value. To properly test
+	 * "As Configured (if Native)" we need to override this value
+	 * in the TD params
+	 */
+	ASSERT_EQ(guest_fma_enabled, 1);
+
+	/* TODO: guest_initial_apic_id is calculated based on the number of
+	 * VCPUs in the TD. From the spec: "Virtual CPU index, starting from 0
+	 * and allocated sequentially on each successful TDH.VP.INIT"
+	 * To test non-trivial values we either need a TD with multiple VCPUs
+	 * or to pick a different calculated value.
+	 */
+	ASSERT_EQ(guest_initial_apic_id, 0);
+
+	kvm_vm_free(vm);
+	printf("\t ... PASSED\n");
+}
 
 int main(int argc, char **argv)
 {
@@ -262,6 +393,7 @@ int main(int argc, char **argv)
 	run_in_new_process(&verify_td_lifecycle);
 	run_in_new_process(&verify_report_fatal_error);
 	run_in_new_process(&verify_td_ioexit);
+	run_in_new_process(&verify_td_cpuid);
 
 	return 0;
 }
