configure, meson: move membarrier test to meson

The test is a bit different from the others, in that it does not run
if $membarrier is empty.  For meson, the default can simply be disabled;
if one day we will toggle the default, no change is needed in meson.build.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

configure

@@ -290,7 +290,6 @@ EXTRA_CXXFLAGS=""
 EXTRA_LDFLAGS=""
 
 xen_ctrl_version="$default_feature"
-membarrier="$default_feature"
 vhost_kernel="$default_feature"
 vhost_net="$default_feature"
 vhost_crypto="$default_feature"
@@ -967,10 +966,6 @@ for opt do
   ;;
   --enable-fdt=*) fdt="$optarg"
   ;;
-  --disable-membarrier) membarrier="no"
-  ;;
-  --enable-membarrier) membarrier="yes"
-  ;;
   --with-pkgversion=*) pkgversion="$optarg"
   ;;
   --with-coroutine=*) coroutine="$optarg"
@@ -1382,7 +1377,6 @@ cat << EOF
   lto             Enable Link-Time Optimization.
   safe-stack      SafeStack Stack Smash Protection. Depends on
                   clang/llvm >= 3.7 and requires coroutine backend ucontext.
-  membarrier      membarrier system call (for Linux 4.14+ or Windows)
   rdma            Enable RDMA-based migration
   pvrdma          Enable PVRDMA support
   vhost-net       vhost-net kernel acceleration support
@@ -2823,37 +2817,6 @@ if test "$fortify_source" != "no"; then
   fi
 fi
 
-##########################################
-# check for usable membarrier system call
-if test "$membarrier" = "yes"; then
-    have_membarrier=no
-    if test "$mingw32" = "yes" ; then
-        have_membarrier=yes
-    elif test "$linux" = "yes" ; then
-        cat > $TMPC << EOF
-    #include <linux/membarrier.h>
-    #include <sys/syscall.h>
-    #include <unistd.h>
-    #include <stdlib.h>
-    int main(void) {
-        syscall(__NR_membarrier, MEMBARRIER_CMD_QUERY, 0);
-        syscall(__NR_membarrier, MEMBARRIER_CMD_SHARED, 0);
-	exit(0);
-    }
-EOF
-        if compile_prog "" "" ; then
-            have_membarrier=yes
-        fi
-    fi
-    if test "$have_membarrier" = "no"; then
-      feature_not_found "membarrier" "membarrier system call not available"
-    fi
-else
-    # Do not enable it by default even for Mingw32, because it doesn't
-    # work on Wine.
-    membarrier=no
-fi
-
 ##########################################
 # check for usable AF_ALG environment
 have_afalg=no
@@ -3315,9 +3278,6 @@ fi
 if test "$vhost_user_fs" = "yes" ; then
   echo "CONFIG_VHOST_USER_FS=y" >> $config_host_mak
 fi
-if test "$membarrier" = "yes" ; then
-  echo "CONFIG_MEMBARRIER=y" >> $config_host_mak
-fi
 if test "$tcg" = "enabled" -a "$tcg_interpreter" = "true" ; then
   echo "CONFIG_TCG_INTERPRETER=y" >> $config_host_mak
 fi

meson.build

@@ -1808,6 +1808,26 @@ config_host_data.set('CONFIG_AVX512F_OPT', get_option('avx512f') \
     int main(int argc, char *argv[]) { return bar(argv[0]); }
   '''), error_message: 'AVX512F not available').allowed())
 
+if get_option('membarrier').disabled()
+  have_membarrier = false
+elif targetos == 'windows'
+  have_membarrier = true
+elif targetos == 'linux'
+  have_membarrier = cc.compiles('''
+    #include <linux/membarrier.h>
+    #include <sys/syscall.h>
+    #include <unistd.h>
+    #include <stdlib.h>
+    int main(void) {
+        syscall(__NR_membarrier, MEMBARRIER_CMD_QUERY, 0);
+        syscall(__NR_membarrier, MEMBARRIER_CMD_SHARED, 0);
+        exit(0);
+    }''')
+endif
+config_host_data.set('CONFIG_MEMBARRIER', get_option('membarrier') \
+  .require(have_membarrier, error_message: 'membarrier system call not available') \
+  .allowed())
+
 config_host_data.set('CONFIG_AF_VSOCK', cc.compiles(gnu_source_prefix + '''
   #include <errno.h>
   #include <sys/types.h>
@@ -3331,7 +3351,7 @@ summary_info += {'link-time optimization (LTO)': get_option('b_lto')}
 summary_info += {'PIE':               get_option('b_pie')}
 summary_info += {'static build':      config_host.has_key('CONFIG_STATIC')}
 summary_info += {'malloc trim support': has_malloc_trim}
-summary_info += {'membarrier':        config_host.has_key('CONFIG_MEMBARRIER')}
+summary_info += {'membarrier':        have_membarrier}
 summary_info += {'debug stack usage': config_host.has_key('CONFIG_DEBUG_STACK_USAGE')}
 summary_info += {'mutex debugging':   config_host.has_key('CONFIG_DEBUG_MUTEX')}
 summary_info += {'memory allocator':  get_option('malloc')}

meson_options.txt

@@ -68,6 +68,12 @@ option('multiprocess', type: 'feature', value: 'auto',
        description: 'Out of process device emulation support')
 option('dbus_display', type: 'feature', value: 'auto',
        description: '-display dbus support')
+
+# Do not enable it by default even for Mingw32, because it doesn't
+# work on Wine.
+option('membarrier', type: 'feature', value: 'disabled',
+       description: 'membarrier system call (for Linux 4.14+ or Windows')
+
 option('avx2', type: 'feature', value: 'auto',
        description: 'AVX2 optimizations')
 option('avx512f', type: 'feature', value: 'disabled',

scripts/meson-buildoptions.sh

@@ -65,6 +65,7 @@ meson_options_help() {
   printf "%s\n" '  lzfse           lzfse support for DMG images'
   printf "%s\n" '  lzo             lzo compression support'
   printf "%s\n" '  malloc-trim     enable libc malloc_trim() for memory optimization'
+  printf "%s\n" '  membarrier      membarrier system call (for Linux 4.14+ or Windows'
   printf "%s\n" '  mpath           Multipath persistent reservation passthrough'
   printf "%s\n" '  multiprocess    Out of process device emulation support'
   printf "%s\n" '  netmap          netmap network backend support'
@@ -204,6 +205,8 @@ _meson_option_parse() {
     --enable-malloc=*) quote_sh "-Dmalloc=$2" ;;
     --enable-malloc-trim) printf "%s" -Dmalloc_trim=enabled ;;
     --disable-malloc-trim) printf "%s" -Dmalloc_trim=disabled ;;
+    --enable-membarrier) printf "%s" -Dmembarrier=enabled ;;
+    --disable-membarrier) printf "%s" -Dmembarrier=disabled ;;
     --enable-mpath) printf "%s" -Dmpath=enabled ;;
     --disable-mpath) printf "%s" -Dmpath=disabled ;;
     --enable-multiprocess) printf "%s" -Dmultiprocess=enabled ;;

util/meson.build

@@ -35,7 +35,9 @@ util_ss.add(files('crc32c.c'))
 util_ss.add(files('uuid.c'))
 util_ss.add(files('getauxval.c'))
 util_ss.add(files('rcu.c'))
-util_ss.add(when: 'CONFIG_MEMBARRIER', if_true: files('sys_membarrier.c'))
+if have_membarrier
+  util_ss.add(files('sys_membarrier.c'))
+endif
 util_ss.add(files('log.c'))
 util_ss.add(files('pagesize.c'))
 util_ss.add(files('qdist.c'))