Re: [RFC PATCH v5 23/29] KVM: selftests: TDX: Add shared memory test

+void guest_shared_mem(void) +{

• uint32_t *test_mem_shared_gva =

• (uint32_t *)TDX_SHARED_MEM_TEST_SHARED_GVA;
  

• uint64_t placeholder;
• uint64_t ret;
• /* Map gpa as shared */
• ret = tdg_vp_vmcall_map_gpa(test_mem_shared_gpa, PAGE_SIZE,

• 		    &placeholder);
  

• if (ret)

• tdx_test_fatal_with_data(ret, __LINE__);
  

• *test_mem_shared_gva = TDX_SHARED_MEM_TEST_GUEST_WRITE_VALUE;
• /* Exit so host can read shared value */
• ret = tdg_vp_vmcall_instruction_io(TDX_SHARED_MEM_TEST_INFO_PORT, 4,

• 			   TDG_VP_VMCALL_INSTRUCTION_IO_WRITE,
  

• 			   &placeholder);
  

• if (ret)

• tdx_test_fatal_with_data(ret, __LINE__);
  

• /* Read value written by host and send it back out for verification */
• ret = tdg_vp_vmcall_instruction_io(TDX_SHARED_MEM_TEST_INFO_PORT, 4,

• 			   TDG_VP_VMCALL_INSTRUCTION_IO_WRITE,
  

• 			   (uint64_t *)test_mem_shared_gva);
  

• if (ret)

• tdx_test_fatal_with_data(ret, __LINE__);
  

+}

+int verify_shared_mem(void) +{

• struct kvm_vm *vm;
• struct kvm_vcpu *vcpu;
• vm_vaddr_t test_mem_private_gva;
• uint32_t *test_mem_hva;
• vm = td_create();
• td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
• vcpu = td_vcpu_add(vm, 0, guest_shared_mem);
• /*

• * Set up shared memory page for testing by first allocating as private
  

• * and then mapping the same GPA again as shared. This way, the TD does
  

• * not have to remap its page tables at runtime.
  

• */
  

• test_mem_private_gva = vm_vaddr_alloc(vm, vm->page_size,

• 			      TDX_SHARED_MEM_TEST_PRIVATE_GVA);
  

• TEST_ASSERT_EQ(test_mem_private_gva, TDX_SHARED_MEM_TEST_PRIVATE_GVA);
• test_mem_hva = addr_gva2hva(vm, test_mem_private_gva);
• TEST_ASSERT(test_mem_hva != NULL,

•     "Guest address not found in guest memory regions\n");
  

• test_mem_private_gpa = addr_gva2gpa(vm, test_mem_private_gva);
• virt_pg_map_shared(vm, TDX_SHARED_MEM_TEST_SHARED_GVA,

• 	   test_mem_private_gpa);
  

• test_mem_shared_gpa = test_mem_private_gpa | BIT_ULL(vm->pa_bits - 1);
• sync_global_to_guest(vm, test_mem_private_gpa);
• sync_global_to_guest(vm, test_mem_shared_gpa);
• td_finalize(vm);
• printf("Verifying shared memory accesses for TDX\n");
• /* Begin guest execution; guest writes to shared memory. */
• printf("\t ... Starting guest execution\n");
• /* Handle map gpa as shared */
• td_vcpu_run(vcpu);
• TDX_TEST_CHECK_GUEST_FAILURE(vcpu);

The first VMExit should be caused by tdvmcall map gpa, so it's impossible to be guest failure.

Move this line TDX_TEST_CHECK_GUEST_FAILURE(vcpu) to after the next td_vcpu_run() is better.

• td_vcpu_run(vcpu);
• TDX_TEST_ASSERT_IO(vcpu, TDX_SHARED_MEM_TEST_INFO_PORT, 4,

• 	   TDG_VP_VMCALL_INSTRUCTION_IO_WRITE);
  

• TEST_ASSERT_EQ(*test_mem_hva, TDX_SHARED_MEM_TEST_GUEST_WRITE_VALUE);
• *test_mem_hva = TDX_SHARED_MEM_TEST_HOST_WRITE_VALUE;
• td_vcpu_run(vcpu);
• TDX_TEST_ASSERT_IO(vcpu, TDX_SHARED_MEM_TEST_INFO_PORT, 4,

• 	   TDG_VP_VMCALL_INSTRUCTION_IO_WRITE);
  

• TEST_ASSERT_EQ(

• *(uint32_t *)((void *)vcpu->run + vcpu->run->io.data_offset),
  

• TDX_SHARED_MEM_TEST_HOST_WRITE_VALUE);
  

• printf("\t ... PASSED\n");
• kvm_vm_free(vm);
• return 0;

+}