configure: Check for virtio-serial support in qemu.

All other vmchannel methods are obsolete, but we were still trying
to check for them.  This replaces all of them with a simple check
for virtio-serial.

diff --git a/configure.ac b/configure.ac
index 422c269..0b60924 100644 (file)
--- a/configure.ac
+++ b/configure.ac
@@ -236,50 +236,24 @@ AC_PATH_PROGS([QEMU],[$with_qemu],[no],
 test "x$QEMU" = "xno" && AC_MSG_ERROR([qemu must be installed])
 AC_DEFINE_UNQUOTED([QEMU],["$QEMU"],[Location of qemu binary.])
 
-dnl Check that the chosen qemu has vmchannel support or we can
-dnl fallback to null vmchannel (still using SLIRP).  See the
-dnl discussion in the README file.
+dnl Check that the chosen qemu has virtio-serial support.
 if test "x$vmchannel_test" != "xno"; then
-    AC_MSG_CHECKING([for guestfwd support in $QEMU])
-    if $QEMU -nographic --help | grep -sq guestfwd; then
+    AC_MSG_CHECKING([for virtio-serial support in $QEMU])
+    if $QEMU -nographic -device \? 2>&1 | grep -sq virtio-serial; then
         AC_MSG_RESULT([yes])
         vmchannel_guestfwd=guestfwd
     else
         AC_MSG_RESULT([no])
-        # Note that this test must be conditional on the previous
-        # test failing.  This is because recent qemu will throw
-        # up an SDL window and hang if we try to run this test.
-        AC_MSG_CHECKING([for "-net channel" (old guestfwd) support in $QEMU])
-        vmchannelout=`$QEMU -nographic -net channel /dev/zero 2>&1 ||:`
-        echo "vmchannel test command output: $vmchannelout" >&AS_MESSAGE_LOG_FD
-        if echo "$vmchannelout" | grep -sq "vmchannel wrong port number" ; then
-            AC_MSG_RESULT([yes])
-            vmchannel_guestfwd=net_channel
-        else
-            AC_MSG_RESULT([no])
-            vmchannel_guestfwd=no
-        fi
-    fi
-
-    AC_MSG_CHECKING([for "-net user" (user mode network) support in $QEMU])
-    if $QEMU -nographic --help | grep -sq -- "-net user"; then
-        AC_MSG_RESULT([yes])
-        vmchannel_net_user=yes
-    else
-        AC_MSG_RESULT([no])
-        vmchannel_net_user=no
-    fi
-
-    if test "x$vmchannel_net_user" = "xno" && test "x$vmchannel_guestfwd" = "xno"; then
         AC_MSG_FAILURE(
-[I did not find user mode network or vmchannel support in
+[I did not find virtio-serial support in
 $QEMU.
 
-Either user mode networking or vmchannel support is vital for
-libguestfs to operate.
+virtio-serial support in qemu or KVM is essential for libguestfs
+to operate.
 
-Please read the relevant section in the README file for more
-information about this.
+Usually this means that you have to install a newer version of qemu
+and/or KVM.  Please read the relevant section in the README file for
+more information about this.
 
 You can override this test by setting the environment variable
 vmchannel_test=no  However if you don't have the right support