tests/qtest: arm: fix operation in a build without any boards or devices

ARM/aarch64 are easy to fix because they already have to pass a machine
type by hand.  Just guard the tests with a check that the machine actually
exists.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20240509170044.190795-14-pbonzini@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tests/qtest/arm-cpu-features.c

@@ -632,6 +632,10 @@ int main(int argc, char **argv)
 {
     g_test_init(&argc, &argv, NULL);
 
+    if (!qtest_has_machine("virt")) {
+        goto out;
+    }
+
     if (qtest_has_accel("tcg")) {
         qtest_add_data_func("/arm/query-cpu-model-expansion",
                             NULL, test_query_cpu_model_expansion);

tests/qtest/migration-test.c

@@ -781,6 +781,12 @@ static int test_migrate_start(QTestState **from, QTestState **to,
         kvm_opts = ",dirty-ring-size=4096";
     }
 
+    if (!qtest_has_machine(machine_alias)) {
+        g_autofree char *msg = g_strdup_printf("machine %s not supported", machine_alias);
+        g_test_skip(msg);
+        return -1;
+    }
+
     machine = resolve_machine_version(machine_alias, QEMU_ENV_SRC,
                                       QEMU_ENV_DST);
 

tests/qtest/numa-test.c

@@ -558,6 +558,9 @@ int main(int argc, char **argv)
     }
 
     if (g_str_equal(arch, "aarch64")) {
+        if (!qtest_has_machine("virt")) {
+            goto out;
+        }
         g_string_append(args, " -machine virt");
     }
 
@@ -590,5 +593,6 @@ int main(int argc, char **argv)
                             aarch64_numa_cpu);
     }
 
+out:
     return g_test_run();
 }