On 12/13/2023 4:46 AM, Sagi Shahar wrote:
From: Erdem Aktas <erdemak...@google.com>

Verifies TDVMCALL<INSTRUCTION.IO> READ and WRITE operations.

Signed-off-by: Erdem Aktas <erdemak...@google.com>
Signed-off-by: Sagi Shahar <sa...@google.com>
Signed-off-by: Ackerley Tng <ackerley...@google.com>
Signed-off-by: Ryan Afranji <afra...@google.com>
---
  .../kvm/include/x86_64/tdx/test_util.h        | 34 ++++++++
  .../selftests/kvm/x86_64/tdx_vm_tests.c       | 82 +++++++++++++++++++
  2 files changed, 116 insertions(+)

One nit comment below.

Reviewed-by: Binbin Wu <binbin...@linux.intel.com>


diff --git a/tools/testing/selftests/kvm/include/x86_64/tdx/test_util.h 
b/tools/testing/selftests/kvm/include/x86_64/tdx/test_util.h
index 6d69921136bd..95a5d5be7f0b 100644
--- a/tools/testing/selftests/kvm/include/x86_64/tdx/test_util.h
+++ b/tools/testing/selftests/kvm/include/x86_64/tdx/test_util.h
@@ -9,6 +9,40 @@
  #define TDX_TEST_SUCCESS_PORT 0x30
  #define TDX_TEST_SUCCESS_SIZE 4
+/**
+ * Assert that some IO operation involving tdg_vp_vmcall_instruction_io() was
+ * called in the guest.
+ */
+#define TDX_TEST_ASSERT_IO(VCPU, PORT, SIZE, DIR)                      \
+       do {                                                            \
+               TEST_ASSERT((VCPU)->run->exit_reason == KVM_EXIT_IO,      \
+                       "Got exit_reason other than KVM_EXIT_IO: %u (%s)\n", \
+                       (VCPU)->run->exit_reason,                 \
+                       exit_reason_str((VCPU)->run->exit_reason));       \
+                                                                       \
+               TEST_ASSERT(((VCPU)->run->exit_reason == KVM_EXIT_IO) && \
+                       ((VCPU)->run->io.port == (PORT)) &&               \
+                       ((VCPU)->run->io.size == (SIZE)) &&               \
+                       ((VCPU)->run->io.direction == (DIR)),             \
+                       "Got unexpected IO exit values: %u (%s) %d %d %d\n", \
+                       (VCPU)->run->exit_reason,                 \
+                       exit_reason_str((VCPU)->run->exit_reason),        \
+                       (VCPU)->run->io.port, (VCPU)->run->io.size, \
+                       (VCPU)->run->io.direction);                       \
+       } while (0)
+
+/**
+ * Check and report if there was some failure in the guest, either an exception
+ * like a triple fault, or if a tdx_test_fatal() was hit.
+ */
+#define TDX_TEST_CHECK_GUEST_FAILURE(VCPU)                             \
+       do {                                                            \
+               if ((VCPU)->run->exit_reason == KVM_EXIT_SYSTEM_EVENT)    \
+                       TEST_FAIL("Guest reported error. error code: %lld 
(0x%llx)\n", \
+                               (VCPU)->run->system_event.data[1],        \
+                               (VCPU)->run->system_event.data[1]);       \
+       } while (0)
+
  /**
   * Assert that tdx_test_success() was called in the guest.
   */
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 8638c7bbedaa..75467c407ca7 100644
--- a/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
+++ b/tools/testing/selftests/kvm/x86_64/tdx_vm_tests.c
@@ -2,6 +2,7 @@
#include <signal.h>
  #include "kvm_util_base.h"
+#include "tdx/tdcall.h"
  #include "tdx/tdx.h"
  #include "tdx/tdx_util.h"
  #include "tdx/test_util.h"
@@ -74,6 +75,86 @@ void verify_report_fatal_error(void)
        printf("\t ... PASSED\n");
  }
+#define TDX_IOEXIT_TEST_PORT 0x50
+
+/*
+ * Verifies IO functionality by writing a |value| to a predefined port.
+ * Verifies that the read value is |value| + 1 from the same port.
+ * If all the tests are passed then write a value to port TDX_TEST_PORT
+ */
+void guest_ioexit(void)
+{
+       uint64_t data_out, data_in, delta;
+       uint64_t ret;
+
+       data_out = 0xAB;
+       ret = tdg_vp_vmcall_instruction_io(TDX_IOEXIT_TEST_PORT, 1,
+                                       TDG_VP_VMCALL_INSTRUCTION_IO_WRITE,
+                                       &data_out);
+       if (ret)
+               tdx_test_fatal(ret);
+
+       ret = tdg_vp_vmcall_instruction_io(TDX_IOEXIT_TEST_PORT, 1,
+                                       TDG_VP_VMCALL_INSTRUCTION_IO_READ,
+                                       &data_in);
+       if (ret)
+               tdx_test_fatal(ret);
+
+       delta = data_in - data_out;
+       if (delta != 1)

Nit: Is it more direct to compare data_in with 0xAC?

+               tdx_test_fatal(ret);
+
+       tdx_test_success();
+}
+
+void verify_td_ioexit(void)
+{
+       struct kvm_vm *vm;
+       struct kvm_vcpu *vcpu;
+
+       uint32_t port_data;
+
+       vm = td_create();
+       td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
+       vcpu = td_vcpu_add(vm, 0, guest_ioexit);
+       td_finalize(vm);
+
+       printf("Verifying TD IO Exit:\n");
+
+       /* Wait for guest to do a IO write */
+       td_vcpu_run(vcpu);
+       TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+       TDX_TEST_ASSERT_IO(vcpu, TDX_IOEXIT_TEST_PORT, 1,
+                       TDG_VP_VMCALL_INSTRUCTION_IO_WRITE);
+       port_data = *(uint8_t *)((void *)vcpu->run + vcpu->run->io.data_offset);
+
+       printf("\t ... IO WRITE: OK\n");
+
+       /*
+        * Wait for the guest to do a IO read. Provide the previous written data
+        * + 1 back to the guest
+        */
+       td_vcpu_run(vcpu);
+       TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+       TDX_TEST_ASSERT_IO(vcpu, TDX_IOEXIT_TEST_PORT, 1,
+                       TDG_VP_VMCALL_INSTRUCTION_IO_READ);
+       *(uint8_t *)((void *)vcpu->run + vcpu->run->io.data_offset) = port_data 
+ 1;
+
+       printf("\t ... IO READ: OK\n");
+
+       /*
+        * Wait for the guest to complete execution successfully. The read
+        * value is checked within the guest.
+        */
+       td_vcpu_run(vcpu);
+       TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
+       TDX_TEST_ASSERT_SUCCESS(vcpu);
+
+       printf("\t ... IO verify read/write values: OK\n");
+       kvm_vm_free(vm);
+       printf("\t ... PASSED\n");
+}
+
  int main(int argc, char **argv)
  {
        setbuf(stdout, NULL);
@@ -85,6 +166,7 @@ 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);
return 0;
  }


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