On 8/8/2025 4:16 AM, Sagi Shahar wrote:
From: Ryan Afranji afranji@google.com
The test checks that host can only read fixed values when trying to access the guest's private memory.
Signed-off-by: Ryan Afranji afranji@google.com Signed-off-by: Sagi Shahar sagis@google.com
tools/testing/selftests/kvm/x86/tdx_vm_test.c | 83 ++++++++++++++++++- 1 file changed, 82 insertions(+), 1 deletion(-)
diff --git a/tools/testing/selftests/kvm/x86/tdx_vm_test.c b/tools/testing/selftests/kvm/x86/tdx_vm_test.c index 2f75f12d2a44..b6ef0348746c 100644 --- a/tools/testing/selftests/kvm/x86/tdx_vm_test.c +++ b/tools/testing/selftests/kvm/x86/tdx_vm_test.c @@ -959,6 +959,85 @@ void verify_td_cpuid_tdcall(void) printf("\t ... PASSED\n"); } +/*
- Shared variables between guest and host for host reading private mem test
- */
+static uint64_t tdx_test_host_read_private_mem_addr; +#define TDX_HOST_READ_PRIVATE_MEM_PORT_TEST 0x53
+void guest_host_read_priv_mem(void) +{
- uint64_t placeholder = 0;
- uint64_t ret;
- /* Set value */
- *((uint32_t *)tdx_test_host_read_private_mem_addr) = 0xABCD;
- /* Exit so host can read value */
- ret = tdg_vp_vmcall_instruction_io(TDX_HOST_READ_PRIVATE_MEM_PORT_TEST,
4, PORT_WRITE, &placeholder);- tdx_assert_error(ret);
- /* Update guest_var's value and have host reread it. */
- *((uint32_t *)tdx_test_host_read_private_mem_addr) = 0xFEDC;
- tdx_test_success();
+}
+void verify_host_reading_private_mem(void) +{
- uint64_t second_host_read;
- uint64_t first_host_read;
- struct kvm_vcpu *vcpu;
- vm_vaddr_t test_page;
- uint64_t *host_virt;
- struct kvm_vm *vm;
- vm = td_create();
- td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
- vcpu = td_vcpu_add(vm, 0, guest_host_read_priv_mem);
- test_page = vm_vaddr_alloc_page(vm);
- TEST_ASSERT(test_page < BIT_ULL(32),
"Test address should fit in 32 bits so it can be sent to the guest");
I didn't understand it. Could you elaborate a bit?
- host_virt = addr_gva2hva(vm, test_page);
- TEST_ASSERT(host_virt,
"Guest address not found in guest memory regions\n");- tdx_test_host_read_private_mem_addr = test_page;
- sync_global_to_guest(vm, tdx_test_host_read_private_mem_addr);
- td_finalize(vm);
- printf("Verifying host's behavior when reading TD private memory:\n");
When the host accesses host_virt, it's not accessing the same page of the private page of the TD, so it's not accurate to say the host is reading or consuming TD private memory.
- tdx_run(vcpu);
- tdx_test_assert_io(vcpu, TDX_HOST_READ_PRIVATE_MEM_PORT_TEST,
4, PORT_WRITE);- printf("\t ... Guest's variable contains 0xABCD\n");
- /* Host reads guest's variable. */
- first_host_read = *host_virt;
- printf("\t ... Host's read attempt value: %lu\n", first_host_read);
- /* Guest updates variable and host rereads it. */
- tdx_run(vcpu);
- printf("\t ... Guest's variable updated to 0xFEDC\n");
- second_host_read = *host_virt;
- printf("\t ... Host's second read attempt value: %lu\n",
second_host_read);- TEST_ASSERT(first_host_read == second_host_read,
"Host did not read a fixed pattern\n");- printf("\t ... Fixed pattern was returned to the host\n");
- kvm_vm_free(vm);
- printf("\t ... PASSED\n");
+}
- int main(int argc, char **argv) { ksft_print_header();
@@ -966,7 +1045,7 @@ int main(int argc, char **argv) if (!is_tdx_enabled()) ksft_exit_skip("TDX is not supported by the KVM. Exiting.\n");
- ksft_set_plan(13);
- ksft_set_plan(14); ksft_test_result(!run_in_new_process(&verify_td_lifecycle), "verify_td_lifecycle\n"); ksft_test_result(!run_in_new_process(&verify_report_fatal_error),
@@ -993,6 +1072,8 @@ int main(int argc, char **argv) "verify_mmio_writes\n"); ksft_test_result(!run_in_new_process(&verify_td_cpuid_tdcall), "verify_td_cpuid_tdcall\n");
- ksft_test_result(!run_in_new_process(&verify_host_reading_private_mem),
"verify_host_reading_private_mem\n");ksft_finished(); return 0;