tests/cpu-policy: Confirm that CPUID serialisation is sorted

The existing x86_cpuid_copy_to_buffer() does produce sorted results, and we're
about to start relying on this.  Extend the unit tests.

As test_cpuid_serialise_success() is a fairly limited set of synthetic
examples right now, introduce test_cpuid_current() to operate on the full
policy for the current CPU.

Tweak the fail() macro to allow for simplified control flow.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
Release-acked-by: Paul Durrant <paul@xen.org>

tools/tests/cpu-policy/test-cpu-policy.c

@@ -16,7 +16,7 @@ static unsigned int nr_failures;
 #define fail(fmt, ...)                          \
 ({                                              \
     nr_failures++;                              \
-    printf(fmt, ##__VA_ARGS__);                 \
+    (void)printf(fmt, ##__VA_ARGS__);           \
 })
 
 #define memdup(ptr)                             \
@@ -66,6 +66,45 @@ static void test_vendor_identification(void)
     }
 }
 
+static bool leaves_are_sorted(const xen_cpuid_leaf_t *leaves, unsigned int nr)
+{
+    for ( unsigned int i = 1; i < nr; ++i )
+    {
+        /* leaf index went backwards => not sorted. */
+        if ( leaves[i - 1].leaf > leaves[i].leaf )
+            return false;
+
+        /* leaf index went forwards => ok */
+        if ( leaves[i - 1].leaf < leaves[i].leaf )
+            continue;
+
+        /* leave index the same, subleaf didn't increase => not sorted. */
+        if ( leaves[i - 1].subleaf >= leaves[i].subleaf )
+            return false;
+    }
+
+    return true;
+}
+
+static void test_cpuid_current(void)
+{
+    struct cpuid_policy p;
+    xen_cpuid_leaf_t leaves[CPUID_MAX_SERIALISED_LEAVES];
+    unsigned int nr = ARRAY_SIZE(leaves);
+    int rc;
+
+    printf("Testing CPUID on current CPU\n");
+
+    x86_cpuid_policy_fill_native(&p);
+
+    rc = x86_cpuid_copy_to_buffer(&p, leaves, &nr);
+    if ( rc != 0 )
+        return fail("  Serialise, expected rc 0, got %d\n", rc);
+
+    if ( !leaves_are_sorted(leaves, nr) )
+        return fail("  Leaves not sorted\n");
+}
+
 static void test_cpuid_serialise_success(void)
 {
     static const struct test {
@@ -178,6 +217,13 @@ static void test_cpuid_serialise_success(void)
             goto test_done;
         }
 
+        if ( !leaves_are_sorted(leaves, nr) )
+        {
+            fail("  Test %s, leaves not sorted\n",
+                 t->name);
+            goto test_done;
+        }
+
     test_done:
         free(leaves);
     }
@@ -613,6 +659,7 @@ int main(int argc, char **argv)
 
     test_vendor_identification();
 
+    test_cpuid_current();
     test_cpuid_serialise_success();
     test_cpuid_deserialise_failure();
     test_cpuid_out_of_range_clearing();