configure, meson: replace VSS SDK checks and options with --enable-vss-sdk

The VSS headers are part of standard MS VS SDK, at least since version
15, and probably before that.

They are also included with MinGW, although currently broken.

Let's streamline a bit the options, by not making it so special, and
instead rely on proper system headers configuration or user
--extra-cxxflags. This still requires some extra step to cross-build
with MinGW as described in the meson.build file now.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
[Use a "feature"-type option. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

configure

@@ -317,7 +317,6 @@ pie=""
 trace_backends="log"
 trace_file="trace"
 opengl="$default_feature"
-vss_win32_sdk="$default_feature"
 coroutine=""
 tls_priority="NORMAL"
 plugins="$default_feature"
@@ -957,12 +956,6 @@ for opt do
   ;;
   --disable-zlib-test)
   ;;
-  --with-vss-sdk) vss_win32_sdk=""
-  ;;
-  --with-vss-sdk=*) vss_win32_sdk="$optarg"
-  ;;
-  --without-vss-sdk) vss_win32_sdk="no"
-  ;;
   --disable-virtio-blk-data-plane|--enable-virtio-blk-data-plane)
       echo "$0: $opt is obsolete, virtio-blk data-plane is always on" >&2
   ;;
@@ -1225,8 +1218,6 @@ Advanced options (experts only):
   --with-coroutine=BACKEND coroutine backend. Supported options:
                            ucontext, sigaltstack, windows
   --enable-gcov            enable test coverage analysis with gcov
-  --with-vss-sdk=SDK-path  enable Windows VSS support in QEMU Guest Agent
-  --with-win-sdk=SDK-path  path to Windows Platform SDK (to build VSS .tlb)
   --tls-priority           default TLS protocol/cipher priority string
   --enable-plugins
                            enable plugins via shared library loading
@@ -2311,41 +2302,6 @@ EOF
   fi
 fi
 
-##########################################
-# check if we have VSS SDK headers for win
-
-guest_agent_with_vss="no"
-if test "$mingw32" = "yes" && \
-        test "$vss_win32_sdk" != "no" ; then
-  case "$vss_win32_sdk" in
-    "")   vss_win32_include="-isystem $source_path" ;;
-    *\ *) # The SDK is installed in "Program Files" by default, but we cannot
-          # handle path with spaces. So we symlink the headers into ".sdk/vss".
-          vss_win32_include="-isystem $source_path/.sdk/vss"
-	  symlink "$vss_win32_sdk/inc" "$source_path/.sdk/vss/inc"
-	  ;;
-    *)    vss_win32_include="-isystem $vss_win32_sdk"
-  esac
-  cat > $TMPC << EOF
-#define __MIDL_user_allocate_free_DEFINED__
-#include <inc/win2003/vss.h>
-int main(void) { return VSS_CTX_BACKUP; }
-EOF
-  if compile_prog "$vss_win32_include" "" ; then
-    guest_agent_with_vss="yes"
-    QEMU_CFLAGS="$QEMU_CFLAGS $vss_win32_include"
-  else
-    if test "$vss_win32_sdk" != "" ; then
-      echo "ERROR: Please download and install Microsoft VSS SDK:"
-      echo "ERROR:   http://www.microsoft.com/en-us/download/details.aspx?id=23490"
-      echo "ERROR: On POSIX-systems, you can extract the SDK headers by:"
-      echo "ERROR:   scripts/extract-vsssdk-headers setup.exe"
-      echo "ERROR: The headers are extracted in the directory \`inc'."
-      feature_not_found "VSS support"
-    fi
-  fi
-fi
-
 ##########################################
 # check if mingw environment provides a recent ntddscsi.h
 guest_agent_ntddscsi="no"
@@ -2875,9 +2831,6 @@ if test "$debug_tcg" = "yes" ; then
 fi
 if test "$mingw32" = "yes" ; then
   echo "CONFIG_WIN32=y" >> $config_host_mak
-  if test "$guest_agent_with_vss" = "yes" ; then
-    echo "CONFIG_QGA_VSS=y" >> $config_host_mak
-  fi
   if test "$guest_agent_ntddscsi" = "yes" ; then
     echo "CONFIG_QGA_NTDDSCSI=y" >> $config_host_mak
   fi

meson.build

@@ -1926,6 +1926,14 @@ config_host_data.set('CONFIG_AF_VSOCK', cc.compiles(gnu_source_prefix + '''
     return -1;
   }'''))
 
+have_vss = false
+if targetos == 'windows' and link_language == 'cpp'
+  have_vss = cxx.compiles('''
+    #define __MIDL_user_allocate_free_DEFINED__
+    #include <inc/win2003/vss.h>
+    int main(void) { return VSS_CTX_BACKUP; }''')
+endif
+
 ignored = ['CONFIG_QEMU_INTERP_PREFIX', # actually per-target
     'HAVE_GDB_BIN']
 arrays = ['CONFIG_BDRV_RW_WHITELIST', 'CONFIG_BDRV_RO_WHITELIST']
@@ -3592,7 +3600,7 @@ summary_info += {'libiscsi support':  libiscsi}
 summary_info += {'libnfs support':    libnfs}
 if targetos == 'windows'
   if have_ga
-    summary_info += {'QGA VSS support':   config_host.has_key('CONFIG_QGA_VSS')}
+    summary_info += {'QGA VSS support':   have_qga_vss}
     summary_info += {'QGA w32 disk info': config_host.has_key('CONFIG_QGA_NTDDSCSI')}
   endif
 endif

meson_options.txt

@@ -42,6 +42,8 @@ option('guest_agent_msi', type : 'feature', value : 'auto',
        description: 'Build MSI package for the QEMU Guest Agent')
 option('tools', type : 'feature', value : 'auto',
        description: 'build support utilities that come with QEMU')
+option('qga_vss', type : 'feature', value: 'auto',
+       description: 'build QGA VSS support (broken with MinGW)')
 
 option('malloc_trim', type : 'feature', value : 'auto',
        description: 'enable libc malloc_trim() for memory optimization')

qga/meson.build

@@ -2,9 +2,26 @@ if not have_ga
   if get_option('guest_agent_msi').enabled()
     error('Guest agent MSI requested, but the guest agent is not being built')
   endif
+  have_qga_vss = false
   subdir_done()
 endif
 
+have_qga_vss = get_option('qga_vss') \
+  .require(targetos == 'windows',
+           error_message: 'VSS support requires Windows') \
+  .require(link_language == 'cpp',
+           error_message: 'VSS support requires a C++ compiler') \
+  .require(have_vss, error_message: '''VSS support requires VSS headers.
+    If your Visual Studio installation doesn't have the VSS headers,
+    Please download and install Microsoft VSS SDK:
+    http://www.microsoft.com/en-us/download/details.aspx?id=23490
+    On POSIX-systems, MinGW doesn't yet provide working headers.
+    you can extract the SDK headers by:
+    $ scripts/extract-vsssdk-headers setup.exe
+    The headers are extracted in the directory 'inc/win2003'.
+    Then run configure with: --extra-cxxflags="-isystem /path/to/vss/inc/win2003"''') \
+  .allowed()
+
 all_qga = []
 
 qga_qapi_outputs = [
@@ -63,7 +80,7 @@ gen_tlb = []
 qga_libs = []
 if targetos == 'windows'
   qga_libs += ['-lws2_32', '-lwinmm', '-lpowrprof', '-lwtsapi32', '-lwininet', '-liphlpapi', '-lnetapi32']
-  if 'CONFIG_QGA_VSS' in config_host
+  if have_qga_vss
     qga_libs += ['-lole32', '-loleaut32', '-lshlwapi', '-lstdc++', '-Wl,--enable-stdcall-fixup']
     subdir('vss-win32')
   endif
@@ -93,7 +110,7 @@ if targetos == 'windows'
   if wixl.found()
     deps = [gen_tlb, qga]
     qemu_ga_msi_vss = []
-    if 'CONFIG_QGA_VSS' in config_host
+    if have_qga_vss
       qemu_ga_msi_vss = ['-D', 'InstallVss']
       deps += qga_vss
     endif

scripts/meson-buildoptions.sh

@@ -20,6 +20,7 @@ meson_options_help() {
   printf "%s\n" '  --enable-malloc=CHOICE   choose memory allocator to use [system] (choices:'
   printf "%s\n" '                           jemalloc/system/tcmalloc)'
   printf "%s\n" '  --enable-profiler        profiler support'
+  printf "%s\n" '  --enable-qga-vss         build QGA VSS support'
   printf "%s\n" '  --enable-qom-cast-debug  cast debugging support'
   printf "%s\n" '  --enable-rng-none        dummy RNG, avoid using /dev/(u)random and'
   printf "%s\n" '                           getrandom()'
@@ -282,6 +283,8 @@ _meson_option_parse() {
     --disable-qcow1) printf "%s" -Dqcow1=disabled ;;
     --enable-qed) printf "%s" -Dqed=enabled ;;
     --disable-qed) printf "%s" -Dqed=disabled ;;
+    --enable-qga-vss) printf "%s" -Dqga_vss=enabled ;;
+    --disable-qga-vss) printf "%s" -Dqga_vss=disabled ;;
     --enable-qom-cast-debug) printf "%s" -Dqom_cast_debug=true ;;
     --disable-qom-cast-debug) printf "%s" -Dqom_cast_debug=false ;;
     --enable-rbd) printf "%s" -Drbd=enabled ;;