cutils: Add test for buffer_is_zero

Signed-off-by: Richard Henderson <rth@twiddle.net>
Message-Id: <1472496380-19706-6-git-send-email-rth@twiddle.net>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

include/qemu/cutils.h

@@ -169,6 +169,7 @@ int64_t qemu_strtosz_suffix_unit(const char *nptr, char **end,
 #define STR_OR_NULL(str) ((str) ? (str) : "null")
 
 bool buffer_is_zero(const void *buf, size_t len);
+bool test_buffer_is_zero_next_accel(void);
 
 /*
  * Implementation of ULEB128 (http://en.wikipedia.org/wiki/LEB128)

tests/Makefile.include

@@ -112,6 +112,8 @@ check-unit-y += tests/test-crypto-xts$(EXESUF)
 check-unit-y += tests/test-crypto-block$(EXESUF)
 gcov-files-test-logging-y = tests/test-logging.c
 check-unit-y += tests/test-logging$(EXESUF)
+check-unit-y += tests/test-bufferiszero$(EXESUF)
+gcov-files-check-bufferiszero-y = util/bufferiszero.c
 
 check-block-$(CONFIG_POSIX) += tests/qemu-iotests-quick.sh
 
@@ -484,6 +486,7 @@ tests/test-qdist$(EXESUF): tests/test-qdist.o $(test-util-obj-y)
 tests/test-qht$(EXESUF): tests/test-qht.o $(test-util-obj-y)
 tests/test-qht-par$(EXESUF): tests/test-qht-par.o tests/qht-bench$(EXESUF) $(test-util-obj-y)
 tests/qht-bench$(EXESUF): tests/qht-bench.o $(test-util-obj-y)
+tests/test-bufferiszero$(EXESUF): tests/test-bufferiszero.o $(test-util-obj-y)
 
 tests/test-qdev-global-props$(EXESUF): tests/test-qdev-global-props.o \
 	hw/core/qdev.o hw/core/qdev-properties.o hw/core/hotplug.o\

tests/test-bufferiszero.c

@@ -0,0 +1,78 @@
+/*
+ * QEMU buffer_is_zero test
+ *
+ * Copyright (c) 2016 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/cutils.h"
+
+static char buffer[8 * 1024 * 1024];
+
+static void test_1(void)
+{
+    size_t s, a, o;
+
+    /* Basic positive test.  */
+    g_assert(buffer_is_zero(buffer, sizeof(buffer)));
+
+    /* Basic negative test.  */
+    buffer[sizeof(buffer) - 1] = 1;
+    g_assert(!buffer_is_zero(buffer, sizeof(buffer)));
+    buffer[sizeof(buffer) - 1] = 0;
+
+    /* Positive tests for size and alignment.  */
+    for (a = 1; a <= 64; a++) {
+        for (s = 1; s < 1024; s++) {
+            buffer[a - 1] = 1;
+            buffer[a + s] = 1;
+            g_assert(buffer_is_zero(buffer + a, s));
+            buffer[a - 1] = 0;
+            buffer[a + s] = 0;
+        }
+    }
+
+    /* Negative tests for size, alignment, and the offset of the marker.  */
+    for (a = 1; a <= 64; a++) {
+        for (s = 1; s < 1024; s++) {
+            for (o = 0; o < s; ++o) {
+                buffer[a + o] = 1;
+                g_assert(!buffer_is_zero(buffer + a, s));
+                buffer[a + o] = 0;
+            }
+        }
+    }
+}
+
+static void test_2(void)
+{
+    if (g_test_perf()) {
+        test_1();
+    } else {
+        do {
+            test_1();
+        } while (test_buffer_is_zero_next_accel());
+    }
+}
+
+int main(int argc, char **argv)
+{
+    g_test_init(&argc, &argv, NULL);
+    g_test_add_func("/cutils/bufferiszero", test_2);
+
+    return g_test_run();
+}

util/bufferiszero.c

@@ -162,6 +162,19 @@ static void __attribute__((constructor)) init_cpuid_cache(void)
     cpuid_cache = cache;
 }
 
+#define HAVE_NEXT_ACCEL
+bool test_buffer_is_zero_next_accel(void)
+{
+    /* If no bits set, we just tested buffer_zero_int, and there
+       are no more acceleration options to test.  */
+    if (cpuid_cache == 0) {
+        return false;
+    }
+    /* Disable the accelerator we used before and select a new one.  */
+    cpuid_cache &= cpuid_cache - 1;
+    return true;
+}
+
 static bool select_accel_fn(const void *buf, size_t len)
 {
     uintptr_t ibuf = (uintptr_t)buf;
@@ -180,6 +193,13 @@ static bool select_accel_fn(const void *buf, size_t len)
 #define select_accel_fn  buffer_zero_int
 #endif
 
+#ifndef HAVE_NEXT_ACCEL
+bool test_buffer_is_zero_next_accel(void)
+{
+    return false;
+}
+#endif
+
 /*
  * Checks if a buffer is all zeroes
  */