Commit 7c2acc70 authored by Peter Maydell's avatar Peter Maydell Committed by Anthony Liguori
Browse files

configure: Don't fall back to gthread coroutine backend 



The gthread coroutine backend is broken and does not produce a working
QEMU; it is only useful for some very limited debugging situations.
Clean up the backend selection logic in configure so that it now runs
"if on windows use windows; else prefer ucontext; else sigaltstack".

To do this we refactor the configure code to separate out "test
whether we have a working ucontext", "pick a default if user didn't
specify" and "validate that user didn't specify something invalid",
rather than having all three of these run together. We also simplify
the Makefile logic so it just links in the backend the configure
script selects.

Signed-off-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Message-id: 1365419487-19867-3-git-send-email-peter.maydell@linaro.org
Signed-off-by: default avatarAnthony Liguori <aliguori@us.ibm.com>
parent 76ad07a4

Makefile.objs

+1 −10
Original line number Diff line number Diff line
@@ -16,16 +16,7 @@ block-obj-y += qapi-types.o qapi-visit.o 


block-obj-y += qemu-coroutine.o qemu-coroutine-lock.o qemu-coroutine-io.o

block-obj-y += qemu-coroutine-sleep.o

ifeq ($(CONFIG_UCONTEXT_COROUTINE),y)

block-obj-$(CONFIG_POSIX) += coroutine-ucontext.o

else

ifeq ($(CONFIG_SIGALTSTACK_COROUTINE),y)

block-obj-$(CONFIG_POSIX) += coroutine-sigaltstack.o

else

block-obj-$(CONFIG_POSIX) += coroutine-gthread.o

endif

endif

block-obj-$(CONFIG_WIN32) += coroutine-win32.o

block-obj-y += coroutine-$(CONFIG_COROUTINE_BACKEND).o



ifeq ($(CONFIG_VIRTIO)$(CONFIG_VIRTFS)$(CONFIG_PCI),yyy)

# Lots of the fsdev/9pcode is pulled in by vl.c via qemu_fsdev_add.

configure

+46 −23
Original line number Diff line number Diff line
@@ -3071,9 +3071,13 @@ fi 
##########################################

# check and set a backend for coroutine



# default is ucontext, but always fallback to gthread

# windows autodetected by make

if test "$coroutine" = "" -o "$coroutine" = "ucontext"; then

# We prefer ucontext, but it's not always possible. The fallback

# is sigcontext. gthread is not selectable except explicitly, because

# it is not functional enough to run QEMU proper. (It is occasionally

# useful for debugging purposes.)  On Windows the only valid backend

# is the Windows-specific one.



ucontext_works=no

if test "$darwin" != "yes"; then

  cat > $TMPC << EOF

#include <ucontext.h>
@@ -3083,19 +3087,42 @@ if test "$coroutine" = "" -o "$coroutine" = "ucontext"; then 
int main(void) { makecontext(0, 0, 0); return 0; }

EOF

  if compile_prog "" "" ; then

        coroutine_backend=ucontext

    else

	coroutine_backend=gthread

    ucontext_works=yes

  fi

fi

elif test "$coroutine" = "gthread" ; then

  coroutine_backend=gthread

elif test "$coroutine" = "windows" ; then

  coroutine_backend=windows

elif test "$coroutine" = "sigaltstack" ; then

  coroutine_backend=sigaltstack



if test "$coroutine" = ""; then

  if test "$mingw32" = "yes"; then

    coroutine=win32

  elif test "$ucontext_works" = "yes"; then

    coroutine=ucontext

  else

    coroutine=sigaltstack

  fi

else

  case $coroutine in

  windows)

    if test "$mingw32" != "yes"; then

      error_exit "'windows' coroutine backend only valid for Windows"

    fi

    # Unfortunately the user visible backend name doesn't match the

    # coroutine-*.c filename for this case, so we have to adjust it here.

    coroutine=win32

    ;;

  ucontext)

    if test "$ucontext_works" != "yes"; then

      feature_not_found "ucontext"

    fi

    ;;

  gthread|sigaltstack)

    if test "$mingw32" = "yes"; then

      error_exit "only the 'windows' coroutine backend is valid for Windows"

    fi

    ;;

  *)

    error_exit "unknown coroutine backend $coroutine"

    ;;

  esac

fi



##########################################
@@ -3402,7 +3429,7 @@ echo "GLX support $glx" 
echo "libiscsi support  $libiscsi"

echo "build guest agent $guest_agent"

echo "seccomp support   $seccomp"

echo "coroutine backend $coroutine_backend"

echo "coroutine backend $coroutine"

echo "GlusterFS support $glusterfs"

echo "virtio-blk-data-plane $virtio_blk_data_plane"

echo "gcov              $gcov_tool"
@@ -3735,11 +3762,7 @@ if test "$rbd" = "yes" ; then 
  echo "CONFIG_RBD=y" >> $config_host_mak

fi



if test "$coroutine_backend" = "ucontext" ; then

  echo "CONFIG_UCONTEXT_COROUTINE=y" >> $config_host_mak

elif test "$coroutine_backend" = "sigaltstack" ; then

  echo "CONFIG_SIGALTSTACK_COROUTINE=y" >> $config_host_mak

fi

echo "CONFIG_COROUTINE_BACKEND=$coroutine" >> $config_host_mak



if test "$open_by_handle_at" = "yes" ; then

  echo "CONFIG_OPEN_BY_HANDLE=y" >> $config_host_mak

tests/Makefile

+1 −13
Original line number Diff line number Diff line
@@ -24,19 +24,7 @@ gcov-files-test-string-input-visitor-y = qapi/string-input-visitor.c 
check-unit-y += tests/test-string-output-visitor$(EXESUF)

gcov-files-test-string-output-visitor-y = qapi/string-output-visitor.c

check-unit-y += tests/test-coroutine$(EXESUF)

ifeq ($(CONFIG_WIN32),y)

gcov-files-test-coroutine-y = coroutine-win32.c

else

ifeq ($(CONFIG_UCONTEXT_COROUTINE),y)

gcov-files-test-coroutine-y = coroutine-ucontext.c

else

ifeq ($(CONFIG_SIGALTSTACK_COROUTINE),y)

gcov-files-test-coroutine-y = coroutine-sigaltstack.c

else

gcov-files-test-coroutine-y = coroutine-gthread.c

endif

endif

endif

gcov-files-test-coroutine-y = coroutine-$(CONFIG_COROUTINE_BACKEND).c

check-unit-y += tests/test-visitor-serialization$(EXESUF)

check-unit-y += tests/test-iov$(EXESUF)

gcov-files-test-iov-y = util/iov.c