qtest: ask endianness of the target in qtest_init()

The target endianness is not deduced anymore from
the architecture name but asked directly to the guest,
using a new qtest command: "endianness". As it can't
change (this is the value of TARGET_WORDS_BIGENDIAN),
we store it to not have to ask every time we want to
know if we have to byte-swap a value.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
CC: Greg Kurz <groug@kaod.org>
CC: David Gibson <david@gibson.dropbear.id.au>
CC: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>

qtest.c

@@ -537,6 +537,13 @@ static void qtest_process_command(CharDriverState *chr, gchar **words)
 
         qtest_send_prefix(chr);
         qtest_send(chr, "OK\n");
+    } else if (strcmp(words[0], "endianness") == 0) {
+        qtest_send_prefix(chr);
+#if defined(TARGET_WORDS_BIGENDIAN)
+        qtest_sendf(chr, "OK big\n");
+#else
+        qtest_sendf(chr, "OK little\n");
+#endif
 #ifdef TARGET_PPC64
     } else if (strcmp(words[0], "rtas") == 0) {
         uint64_t res, args, ret;

tests/libqos/virtio-pci.c

@@ -86,7 +86,7 @@ static uint64_t qvirtio_pci_config_readq(QVirtioDevice *d, uint64_t addr)
     int i;
     uint64_t u64 = 0;
 
-    if (qtest_big_endian()) {
+    if (target_big_endian()) {
         for (i = 0; i < 8; ++i) {
             u64 |= (uint64_t)qpci_io_readb(dev->pdev,
                                 (void *)(uintptr_t)addr + i) << (7 - i) * 8;

tests/libqtest.c

@@ -37,6 +37,7 @@ struct QTestState
     bool irq_level[MAX_IRQ];
     GString *rx;
     pid_t qemu_pid;  /* our child QEMU process */
+    bool big_endian;
 };
 
 static GHookList abrt_hooks;
@@ -47,6 +48,8 @@ static struct sigaction sigact_old;
     g_assert_cmpint(ret, !=, -1); \
 } while (0)
 
+static int qtest_query_target_endianness(QTestState *s);
+
 static int init_socket(const char *socket_path)
 {
     struct sockaddr_un addr;
@@ -209,6 +212,10 @@ QTestState *qtest_init(const char *extra_args)
         kill(s->qemu_pid, SIGSTOP);
     }
 
+    /* ask endianness of the target */
+
+    s->big_endian = qtest_query_target_endianness(s);
+
     return s;
 }
 
@@ -342,6 +349,20 @@ redo:
     return words;
 }
 
+static int qtest_query_target_endianness(QTestState *s)
+{
+    gchar **args;
+    int big_endian;
+
+    qtest_sendf(s, "endianness\n");
+    args = qtest_rsp(s, 1);
+    g_assert(strcmp(args[1], "big") == 0 || strcmp(args[1], "little") == 0);
+    big_endian = strcmp(args[1], "big") == 0;
+    g_strfreev(args);
+
+    return big_endian;
+}
+
 typedef struct {
     JSONMessageParser parser;
     QDict *response;
@@ -886,50 +907,7 @@ char *hmp(const char *fmt, ...)
     return ret;
 }
 
-bool qtest_big_endian(void)
+bool qtest_big_endian(QTestState *s)
 {
-    const char *arch = qtest_get_arch();
-    int i;
-
-    static const struct {
-        const char *arch;
-        bool big_endian;
-    } endianness[] = {
-        { "aarch64", false },
-        { "alpha", false },
-        { "arm", false },
-        { "cris", false },
-        { "i386", false },
-        { "lm32", true },
-        { "m68k", true },
-        { "microblaze", true },
-        { "microblazeel", false },
-        { "mips", true },
-        { "mips64", true },
-        { "mips64el", false },
-        { "mipsel", false },
-        { "moxie", true },
-        { "or32", true },
-        { "ppc", true },
-        { "ppc64", true },
-        { "ppcemb", true },
-        { "s390x", true },
-        { "sh4", false },
-        { "sh4eb", true },
-        { "sparc", true },
-        { "sparc64", true },
-        { "unicore32", false },
-        { "x86_64", false },
-        { "xtensa", false },
-        { "xtensaeb", true },
-        {},
-    };
-
-    for (i = 0; endianness[i].arch; i++) {
-        if (strcmp(endianness[i].arch, arch) == 0) {
-            return endianness[i].big_endian;
-        }
-    }
-
-    return false;
+    return s->big_endian;
 }

tests/libqtest.h

@@ -409,6 +409,14 @@ int64_t qtest_clock_step(QTestState *s, int64_t step);
  */
 int64_t qtest_clock_set(QTestState *s, int64_t val);
 
+/**
+ * qtest_big_endian:
+ * @s: QTestState instance to operate on.
+ *
+ * Returns: True if the architecture under test has a big endian configuration.
+ */
+bool qtest_big_endian(QTestState *s);
+
 /**
  * qtest_get_arch:
  *
@@ -874,12 +882,14 @@ static inline int64_t clock_set(int64_t val)
 }
 
 /**
- * qtest_big_endian:
+ * target_big_endian:
  *
  * Returns: True if the architecture under test has a big endian configuration.
  */
-bool qtest_big_endian(void);
-
+static inline bool target_big_endian(void)
+{
+    return qtest_big_endian(global_qtest);
+}
 
 QDict *qmp_fd_receive(int fd);
 void qmp_fd_sendv(int fd, const char *fmt, va_list ap);

tests/virtio-blk-test.c

@@ -125,7 +125,7 @@ static inline void virtio_blk_fix_request(QVirtioBlkReq *req)
     bool host_endian = false;
 #endif
 
-    if (qtest_big_endian() != host_endian) {
+    if (target_big_endian() != host_endian) {
         req->type = bswap32(req->type);
         req->ioprio = bswap32(req->ioprio);
         req->sector = bswap64(req->sector);