[Qemu-devel] [PATCH v2 2/5] backdoor: Add build infrastructure

[Lluís Vilanova]

Signed-off-by: Lluís Vilanova <address@hidden>
---
 Makefile                      |    4 +++-
 Makefile.objs                 |   18 ++++++++++++++++++
 Makefile.target               |    4 +++-
 backdoor/qemu/qemu-backdoor.h |   31 +++++++++++++++++++++++++++++++
 configure                     |   32 ++++++++++++++++++++++++++++++++
 5 files changed, 87 insertions(+), 2 deletions(-)
 create mode 100644 backdoor/qemu/qemu-backdoor.h

diff --git a/Makefile b/Makefile
index 301c75e..5f89058 100644
--- a/Makefile
+++ b/Makefile
@@ -42,7 +42,9 @@ else
 DOCS=
 endif
 
-SUBDIR_MAKEFLAGS=$(if $(V),,--no-print-directory) BUILD_DIR=$(BUILD_DIR)
+SUBDIR_MAKEFLAGS_=$(if $(V),,--no-print-directory) BUILD_DIR=$(BUILD_DIR)
+# make sure the variable is available to makes in sub-directories
+SUBDIR_MAKEFLAGS=$(SUBDIR_MAKEFLAGS_) SUBDIR_MAKEFLAGS="$(SUBDIR_MAKEFLAGS_)"
 SUBDIR_DEVICES_MAK=$(patsubst %, %/config-devices.mak, $(TARGET_DIRS))
 SUBDIR_DEVICES_MAK_DEP=$(patsubst %, %/config-devices.mak.d, $(TARGET_DIRS))
 
diff --git a/Makefile.objs b/Makefile.objs
index d7a6539..df943e9 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -398,6 +398,24 @@ trace-obj-y += $(addprefix trace/, $(trace-nested-y))
 $(trace-obj-y): $(GENERATED_HEADERS)
 
 ######################################################################
+# backdoor
+
+backdoor-obj-y += $(addprefix backdoor/qemu/, $(backdoor-nested-y))
+
+ifdef CONFIG_BACKDOOR
+LIBBACKDOOR = libbackdoor/libbackdoor.a
+
+.PHONY: force
+force:
+
+$(LIBBACKDOOR): $(dir $(LIBBACKDOOR))/Makefile force
+       $(call quiet-command,$(MAKE) $(SUBDIR_MAKEFLAGS) -C $(dir $@)   \
+               QEMU_CFLAGS="$(QEMU_CFLAGS) -I$(BUILD_DIR)"             \
+               TARGET_DIR="$(TARGET_DIR)$(dir $@)/" VPATH="$(VPATH)"   \
+               SRC_PATH="$(SRC_PATH)" V="$(V)" "$(notdir $@)")
+endif
+
+######################################################################
 # smartcard
 
 libcacard-y = cac.o event.o vcard.o vreader.o vcard_emul_nss.o 
vcard_emul_type.o card_7816.o
diff --git a/Makefile.target b/Makefile.target
index e244040..9533469 100644
--- a/Makefile.target
+++ b/Makefile.target
@@ -90,6 +90,8 @@ libobj-$(CONFIG_TCI_DIS) += tci-dis.o
 
 tci-dis.o: QEMU_CFLAGS += -I$(SRC_PATH)/tcg -I$(SRC_PATH)/tcg/tci
 
+libobj-$(CONFIG_BACKDOOR) += $(backdoor-obj-y)
+
 $(libobj-y): $(GENERATED_HEADERS)
 
 # libqemu
@@ -413,7 +415,7 @@ endif # CONFIG_LINUX_USER
 
 obj-$(CONFIG_GDBSTUB_XML) += gdbstub-xml.o
 
-$(QEMU_PROG): $(obj-y) $(obj-$(TARGET_BASE_ARCH)-y)
+$(QEMU_PROG): $(obj-y) $(obj-$(TARGET_BASE_ARCH)-y) $(LIBBACKDOOR)
        $(call LINK,$^)
 
 
diff --git a/backdoor/qemu/qemu-backdoor.h b/backdoor/qemu/qemu-backdoor.h
new file mode 100644
index 0000000..05e960d
--- /dev/null
+++ b/backdoor/qemu/qemu-backdoor.h
@@ -0,0 +1,31 @@
+/*
+ * QEMU-side user-provided callbacks for the backdoor communication channel.
+ *
+ * Copyright (C) 2011 Lluís Vilanova <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include <stdint.h>
+#include <sys/types.h>
+
+
+/**
+ * Initialize the backdoor channel.
+ *
+ * @param data_size Size of the data channel.
+ */
+void qemu_backdoor_init(uint64_t data_size);
+
+/**
+ * Handle an invocation of the backdoor channel.
+ *
+ * The command argument can be used to achieve concurrency among different
+ * clients (e.g., threads in the guest system) of the backdoor channel (e.g.,
+ * different clients write to different parts of the data channel).
+ *
+ * @param cmd  Command to invoke.
+ * @param data Pointer to the beginning of the data channel.
+ */
+void qemu_backdoor(uint64_t cmd, void *data);
diff --git a/configure b/configure
index ac4840d..f362ef6 100755
--- a/configure
+++ b/configure
@@ -176,6 +176,7 @@ pie=""
 zero_malloc=""
 trace_backend="nop"
 trace_file="trace"
+backdoor=""
 spice=""
 rbd=""
 smartcard=""
@@ -549,6 +550,8 @@ for opt do
   ;;
   --with-trace-file=*) trace_file="$optarg"
   ;;
+  --with-backdoor=*) backdoor="$optarg"
+  ;;
   --enable-gprof) gprof="yes"
   ;;
   --static)
@@ -1062,6 +1065,7 @@ echo "  --enable-trace-backend=B Set trace backend"
 echo "                           Available backends:" 
$("$source_path"/scripts/tracetool --list-backends)
 echo "  --with-trace-file=NAME   Full PATH,NAME of file to store traces"
 echo "                           Default:trace-<pid>"
+echo "  --with-backdoor=PATH     Directory to build user-provided backdoor 
library"
 echo "  --disable-spice          disable spice"
 echo "  --enable-spice           enable spice"
 echo "  --enable-rbd             enable building the rados block device (rbd)"
@@ -2619,6 +2623,20 @@ if test "$trace_backend" = "dtrace"; then
 fi
 
 ##########################################
+# check for a valid directory for backdoor
+if test -n "$backdoor"; then
+    if test ! -f "$backdoor/Makefile"; then
+        echo
+        echo "Error: cannot make into '$backdoor'"
+        echo "Please choose a directory where I can run 'make'"
+        echo
+        exit 1
+    fi
+    backdoor=`readlink -f "$backdoor"`
+fi
+
+
+##########################################
 # __sync_fetch_and_and requires at least -march=i486. Many toolchains
 # use i686 as default anyway, but for those that don't, an explicit
 # specification is necessary
@@ -2838,6 +2856,9 @@ echo "uuid support      $uuid"
 echo "vhost-net support $vhost_net"
 echo "Trace backend     $trace_backend"
 echo "Trace output file $trace_file-<pid>"
+if test -n "$backdoor"; then
+    echo "Backdoor lib dir  $backdoor"
+fi
 echo "spice support     $spice"
 echo "rbd support       $rbd"
 echo "xfsctl support    $xfs"
@@ -3231,6 +3252,13 @@ if test "$trace_default" = "yes"; then
   echo "CONFIG_TRACE_DEFAULT=y" >> $config_host_mak
 fi
 
+# backdoor channel
+if test -n "$backdoor"; then
+  echo "CONFIG_BACKDOOR=y" >> $config_host_mak
+  echo "BACKDOOR_PATH=\"$backdoor\"" >> $config_host_mak
+  QEMU_CFLAGS="-I\"$backdoor\" $QEMU_CFLAGS"
+fi
+
 echo "TOOLS=$tools" >> $config_host_mak
 echo "CHECKS=$checks" >> $config_host_mak
 echo "ROMS=$roms" >> $config_host_mak
@@ -3342,6 +3370,10 @@ if test "$target" = "arm-linux-user" -o "$target" = 
"armeb-linux-user" -o "$targ
   mkdir -p $target_dir/nwfpe
 fi
 symlink $source_path/Makefile.target $target_dir/Makefile
+if test -n "$backdoor"; then
+    mkdir -p $target_dir/libbackdoor
+    symlink $backdoor/Makefile $target_dir/libbackdoor/Makefile
+fi
 
 
 echo "# Automatically generated by configure - do not modify" > 
$config_target_mak