qapi: add 'query-target' command to return target arch

Add a 'query-target' QAPI command to allow management applications
to determine what target architecture a QEMU binary is emulating
without having to parse the binary name or -help output

  $ qmp-shell -p /tmp/qemu
  (QEMU) query-target
  {   u'return': {   u'arch': u'x86_64' }}

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

arch_init.c

@@ -44,6 +44,7 @@
 #include "exec-memory.h"
 #include "hw/pcspk.h"
 #include "qemu/page_cache.h"
+#include "qmp-commands.h"
 
 #ifdef DEBUG_ARCH_INIT
 #define DPRINTF(fmt, ...) \
@@ -1080,3 +1081,13 @@ int xen_available(void)
     return 0;
 #endif
 }
+
+
+TargetInfo *qmp_query_target(Error **errp)
+{
+    TargetInfo *info = g_malloc0(sizeof(*info));
+
+    info->arch = TARGET_TYPE;
+
+    return info;
+}

configure

@@ -3834,14 +3834,19 @@ case "$target_arch2" in
   ;;
 esac
 
+upper() {
+    echo "$@"| LC_ALL=C tr '[a-z]' '[A-Z]'
+}
+
 echo "TARGET_SHORT_ALIGNMENT=$target_short_alignment" >> $config_target_mak
 echo "TARGET_INT_ALIGNMENT=$target_int_alignment" >> $config_target_mak
 echo "TARGET_LONG_ALIGNMENT=$target_long_alignment" >> $config_target_mak
 echo "TARGET_LLONG_ALIGNMENT=$target_llong_alignment" >> $config_target_mak
 echo "TARGET_ARCH=$TARGET_ARCH" >> $config_target_mak
-target_arch_name="`echo $TARGET_ARCH | LC_ALL=C tr '[a-z]' '[A-Z]'`"
+target_arch_name="`upper $TARGET_ARCH`"
 echo "TARGET_$target_arch_name=y" >> $config_target_mak
 echo "TARGET_ARCH2=$target_arch2" >> $config_target_mak
+echo "TARGET_TYPE=TARGET_TYPE_`upper $target_arch2`" >> $config_target_mak
 echo "TARGET_BASE_ARCH=$TARGET_BASE_ARCH" >> $config_target_mak
 if [ "$TARGET_ABI_DIR" = "" ]; then
   TARGET_ABI_DIR=$TARGET_ARCH

qapi-schema.json

@@ -2454,3 +2454,42 @@
 #
 ##
 { 'command': 'query-fdsets', 'returns': ['FdsetInfo'] }
+
+##
+# @TargetType
+#
+# Target CPU emulation type
+#
+# These parameters correspond to the softmmu binary CPU name that is currently
+# running.
+#
+# Since: 1.2.0
+##
+{ 'enum': 'TargetType',
+  'data': [ 'alpha', 'arm', 'cris', 'i386', 'lm32', 'm68k', 'microblazeel',
+            'microblaze', 'mips64el', 'mips64', 'mipsel', 'mips', 'or32',
+            'ppc64', 'ppcemb', 'ppc', 's390x', 'sh4eb', 'sh4', 'sparc64',
+            'sparc', 'unicore32', 'x86_64', 'xtensaeb', 'xtensa' ] }
+
+##
+# @TargetInfo:
+#
+# Information describing the QEMU target.
+#
+# @arch: the target architecture (eg "x86_64", "i386", etc)
+#
+# Since: 1.2.0
+##
+{ 'type': 'TargetInfo',
+  'data': { 'arch': 'TargetType' } }
+
+##
+# @query-target:
+#
+# Return information about the target for this QEMU
+#
+# Returns: TargetInfo
+#
+# Since: 1.2.0
+##
+{ 'command': 'query-target', 'returns': 'TargetInfo' }

qmp-commands.hx

@@ -2509,3 +2509,8 @@ EQMP
         .mhandler.cmd_new = qmp_marshal_input_query_cpu_definitions,
     },
 
+    {
+        .name       = "query-target",
+        .args_type  = "",
+        .mhandler.cmd_new = qmp_marshal_input_query_target,
+    },