selftests: kvm: split "launch" phase of SEV VM creation

Allow the caller to set the initial state of the VM.  Doing this
before sev_vm_launch() matters for SEV-ES, since that is the
place where the VMSA is updated and after which the guest state
becomes sealed.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20240404121327.3107131-17-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/include/x86_64/sev.h

@@ -31,8 +31,9 @@ void sev_vm_launch(struct kvm_vm *vm, uint32_t policy);
 void sev_vm_launch_measure(struct kvm_vm *vm, uint8_t *measurement);
 void sev_vm_launch_finish(struct kvm_vm *vm);
 
-struct kvm_vm *vm_sev_create_with_one_vcpu(uint32_t policy, void *guest_code,
+struct kvm_vm *vm_sev_create_with_one_vcpu(uint32_t type, void *guest_code,
 					   struct kvm_vcpu **cpu);
+void vm_sev_launch(struct kvm_vm *vm, uint32_t policy, uint8_t *measurement);
 
 kvm_static_assert(SEV_RET_SUCCESS == 0);
 

tools/testing/selftests/kvm/lib/x86_64/sev.c

@@ -113,26 +113,30 @@ void sev_vm_launch_finish(struct kvm_vm *vm)
 	TEST_ASSERT_EQ(status.state, SEV_GUEST_STATE_RUNNING);
 }
 
-struct kvm_vm *vm_sev_create_with_one_vcpu(uint32_t policy, void *guest_code,
+struct kvm_vm *vm_sev_create_with_one_vcpu(uint32_t type, void *guest_code,
 					   struct kvm_vcpu **cpu)
 {
 	struct vm_shape shape = {
 		.mode = VM_MODE_DEFAULT,
-		.type = policy & SEV_POLICY_ES ? KVM_X86_SEV_ES_VM : KVM_X86_SEV_VM,
+		.type = type,
 	};
 	struct kvm_vm *vm;
 	struct kvm_vcpu *cpus[1];
-	uint8_t measurement[512];
 
 	vm = __vm_create_with_vcpus(shape, 1, 0, guest_code, cpus);
 	*cpu = cpus[0];
 
+	return vm;
+}
+
+void vm_sev_launch(struct kvm_vm *vm, uint32_t policy, uint8_t *measurement)
+{
 	sev_vm_launch(vm, policy);
 
-	/* TODO: Validate the measurement is as expected. */
+	if (!measurement)
+		measurement = alloca(256);
+
 	sev_vm_launch_measure(vm, measurement);
 
 	sev_vm_launch_finish(vm);
-
-	return vm;
 }

tools/testing/selftests/kvm/x86_64/sev_smoke_test.c

@@ -41,7 +41,12 @@ static void test_sev(void *guest_code, uint64_t policy)
 	struct kvm_vm *vm;
 	struct ucall uc;
 
-	vm = vm_sev_create_with_one_vcpu(policy, guest_code, &vcpu);
+	uint32_t type = policy & SEV_POLICY_ES ? KVM_X86_SEV_ES_VM : KVM_X86_SEV_VM;
+
+	vm = vm_sev_create_with_one_vcpu(type, guest_code, &vcpu);
+
+	/* TODO: Validate the measurement is as expected. */
+	vm_sev_launch(vm, policy, NULL);
 
 	for (;;) {
 		vcpu_run(vcpu);