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 Signed-off-by: Ackerley Tng ackerleytng@google.com --- .../selftests/kvm/x86_64/tdx_vm_tests.c | 85 +++++++++++++++++++ 1 file changed, 85 insertions(+)
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 6935604d768b..c977223ff871 100644 --- a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c +++ b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c @@ -1062,6 +1062,90 @@ 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 ret; + uint64_t placeholder = 0; + + /* 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, + TDG_VP_VMCALL_INSTRUCTION_IO_WRITE, &placeholder); + if (ret) + tdx_test_fatal(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) +{ + struct kvm_vm *vm; + struct kvm_vcpu *vcpu; + + vm_vaddr_t test_page; + uint64_t *host_virt; + uint64_t first_host_read; + uint64_t second_host_read; + + 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"); + + host_virt = addr_gva2hva(vm, test_page); + TEST_ASSERT(host_virt != NULL, + "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"); + + td_vcpu_run(vcpu); + TDX_TEST_CHECK_GUEST_FAILURE(vcpu); + TDX_TEST_ASSERT_IO(vcpu, TDX_HOST_READ_PRIVATE_MEM_PORT_TEST, + 4, TDG_VP_VMCALL_INSTRUCTION_IO_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. */ + td_vcpu_run(vcpu); + TDX_TEST_CHECK_GUEST_FAILURE(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) { setbuf(stdout, NULL); @@ -1084,6 +1168,7 @@ int main(int argc, char **argv) run_in_new_process(&verify_mmio_reads); run_in_new_process(&verify_mmio_writes); run_in_new_process(&verify_td_cpuid_tdcall); + run_in_new_process(&verify_host_reading_private_mem);
return 0; }