[RFC PATCH v3 31/31] KVM: selftests: TDX: Add TDX UPM selftests for implicit conversion

[Ackerley Tng]

This tests the use of restricted memory without explicit MapGPA calls.

Signed-off-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>
---
 .../selftests/kvm/x86_64/tdx_upm_test.c       | 88 ++++++++++++++++---
 1 file changed, 78 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86_64/tdx_upm_test.c b/tools/testing/selftests/kvm/x86_64/tdx_upm_test.c
index 13914aebd7da7..56ba3d4fb15a5 100644
--- a/tools/testing/selftests/kvm/x86_64/tdx_upm_test.c
+++ b/tools/testing/selftests/kvm/x86_64/tdx_upm_test.c
@@ -149,11 +149,18 @@ enum {
  * Does vcpu_run, and also manages memory conversions if requested by the TD.
  */
 void vcpu_run_and_manage_memory_conversions(struct kvm_vm *vm,
-					    struct kvm_vcpu *vcpu)
+					    struct kvm_vcpu *vcpu, bool handle_conversions)
 {
 	for (;;) {
 		vcpu_run(vcpu);
-		if (
+		if (handle_conversions &&
+			vcpu->run->exit_reason == KVM_EXIT_MEMORY_FAULT) {
+			handle_memory_conversion(
+				vm, vcpu->run->memory.gpa,
+				vcpu->run->memory.size,
+				vcpu->run->memory.flags == KVM_MEMORY_EXIT_FLAG_PRIVATE);
+			continue;
+		} else if (
 			vcpu->run->exit_reason == KVM_EXIT_IO &&
 			vcpu->run->io.port == TDX_UPM_TEST_ACCEPT_PRINT_PORT) {
 			uint64_t gpa = tdx_test_read_64bit(
@@ -233,8 +240,53 @@ static void guest_upm_explicit(void)
 	tdx_test_success();
 }
 
+static void guest_upm_implicit(void)
+{
+	struct tdx_upm_test_area *test_area_gva_private =
+		(struct tdx_upm_test_area *)TDX_UPM_TEST_AREA_GVA_PRIVATE;
+	struct tdx_upm_test_area *test_area_gva_shared =
+		(struct tdx_upm_test_area *)TDX_UPM_TEST_AREA_GVA_SHARED;
+
+	/* Check: host reading private memory does not modify guest's view */
+	fill_test_area(test_area_gva_private, PATTERN_GUEST_GENERAL);
+
+	tdx_test_report_to_user_space(SYNC_CHECK_READ_PRIVATE_MEMORY_FROM_HOST);
+
+	TDX_UPM_TEST_ASSERT(
+		check_test_area(test_area_gva_private, PATTERN_GUEST_GENERAL));
+
+	/* Use focus area as shared */
+	fill_focus_area(test_area_gva_shared, PATTERN_GUEST_FOCUS);
+
+	/* General areas should not be affected */
+	TDX_UPM_TEST_ASSERT(
+		check_general_areas(test_area_gva_private, PATTERN_GUEST_GENERAL));
+
+	tdx_test_report_to_user_space(SYNC_CHECK_READ_SHARED_MEMORY_FROM_HOST);
+
+	/* Check that guest has the same view of shared memory */
+	TDX_UPM_TEST_ASSERT(
+		check_focus_area(test_area_gva_shared, PATTERN_HOST_FOCUS));
+
+	/* Use focus area as private */
+	fill_focus_area(test_area_gva_private, PATTERN_GUEST_FOCUS);
+
+	/* General areas should be unaffected by remapping */
+	TDX_UPM_TEST_ASSERT(
+		check_general_areas(test_area_gva_private, PATTERN_GUEST_GENERAL));
+
+	tdx_test_report_to_user_space(SYNC_CHECK_READ_PRIVATE_MEMORY_FROM_HOST_AGAIN);
+
+	/* Check that guest can use private memory after focus area is remapped as private */
+	TDX_UPM_TEST_ASSERT(
+		fill_and_check(test_area_gva_private, PATTERN_GUEST_GENERAL));
+
+	tdx_test_success();
+}
+
 static void run_selftest(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
-			 struct tdx_upm_test_area *test_area_base_hva)
+			 struct tdx_upm_test_area *test_area_base_hva,
+			 bool implicit)
 {
 	vcpu_run(vcpu);
 	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
@@ -253,7 +305,7 @@ static void run_selftest(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
 	TEST_ASSERT(check_test_area(test_area_base_hva, PATTERN_CONFIDENCE_CHECK),
 		"Host should read PATTERN_CONFIDENCE_CHECK from guest's private memory.");
 
-	vcpu_run_and_manage_memory_conversions(vm, vcpu);
+	vcpu_run_and_manage_memory_conversions(vm, vcpu, implicit);
 	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
 	TDX_TEST_ASSERT_IO(vcpu, TDX_TEST_REPORT_PORT, TDX_TEST_REPORT_SIZE,
 		 TDG_VP_VMCALL_INSTRUCTION_IO_WRITE);
@@ -270,7 +322,7 @@ static void run_selftest(struct kvm_vm *vm, struct kvm_vcpu *vcpu,
 	TEST_ASSERT(check_focus_area(test_area_base_hva, PATTERN_HOST_FOCUS),
 		    "Host should be able to use shared memory.");
 
-	vcpu_run_and_manage_memory_conversions(vm, vcpu);
+	vcpu_run_and_manage_memory_conversions(vm, vcpu, implicit);
 	TDX_TEST_CHECK_GUEST_FAILURE(vcpu);
 	TDX_TEST_ASSERT_IO(vcpu, TDX_TEST_REPORT_PORT, TDX_TEST_REPORT_SIZE,
 		 TDG_VP_VMCALL_INSTRUCTION_IO_WRITE);
@@ -319,18 +371,20 @@ static void guest_ve_handler(struct ex_regs *regs)
 	TDX_UPM_TEST_ASSERT(!ret);
 }
 
-static void verify_upm_test(void)
+static void verify_upm_test(bool implicit)
 {
 	struct kvm_vm *vm;
 	struct kvm_vcpu *vcpu;
 
+	void *guest_code;
 	vm_vaddr_t test_area_gva_private;
 	struct tdx_upm_test_area *test_area_base_hva;
 	uint64_t test_area_npages;
 
 	vm = td_create();
 	td_initialize(vm, VM_MEM_SRC_ANONYMOUS, 0);
-	vcpu = td_vcpu_add(vm, 0, guest_upm_explicit);
+	guest_code = implicit ? guest_upm_implicit : guest_upm_explicit;
+	vcpu = td_vcpu_add(vm, 0, guest_code);
 
 	vm_install_exception_handler(vm, VE_VECTOR, guest_ve_handler);
 
@@ -370,13 +424,26 @@ static void verify_upm_test(void)
 
 	td_finalize(vm);
 
-	printf("Verifying UPM functionality: explicit MapGPA\n");
+	if (implicit)
+		printf("Verifying UPM functionality: implicit conversion\n");
+	else
+		printf("Verifying UPM functionality: explicit MapGPA\n");
 
-	run_selftest(vm, vcpu, test_area_base_hva);
+	run_selftest(vm, vcpu, test_area_base_hva, implicit);
 
 	kvm_vm_free(vm);
 }
 
+void verify_upm_test_explicit(void)
+{
+	verify_upm_test(false);
+}
+
+void verify_upm_test_implicit(void)
+{
+	verify_upm_test(true);
+}
+
 int main(int argc, char **argv)
 {
 	/* Disable stdout buffering */
@@ -388,5 +455,6 @@ int main(int argc, char **argv)
 		return 0;
 	}
 
-	run_in_new_process(&verify_upm_test);
+	run_in_new_process(&verify_upm_test_explicit);
+	run_in_new_process(&verify_upm_test_implicit);
 }
-- 
2.39.0.246.g2a6d74b583-goog