HV: make: introduce targets for generating configs

This patch implements the following targets as an includable .mk to the make
system of the hypervisor.

    make defconfig PLATFORM=xx:
        force (re)generating the default configuration for xx

    make oldconfig PLATFORM=xx:
        generate a configuration for platform xx based on .config if available

    make minimalconfig
        save a minimized .config to defconfig

The default target (make all) will generate a default configuration if no
.config is available.

The values defined in .config are available in the toplevel Makefile after
kconfig/kconfig.mk is included.

v4 -> v5:

    * Add minimalconfig for generating default configs.

v3 -> v4:

    * No changes.

v2 -> v3:

    * "make defconfig" now correctly overwrite an existing .config.
    * Add short descriptions on where each target is supposed to be used.

v1 -> v2:

    * Add proper dependency checks in the Makefile of hypervisor.

Signed-off-by: Junjie Mao <junjie.mao@intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Zhao Yakui <yakui.zhao@intel.com>

hypervisor/Makefile

@@ -22,6 +22,13 @@ PLATFORM ?= sbl
 HV_OBJDIR ?= $(CURDIR)/build
 HV_FILE := acrn
 
+.PHONY: default
+default: all
+
+include $(BASEDIR)/../scripts/deps.mk
+
+include scripts/kconfig/kconfig.mk
+
 CFLAGS += -Wall -W
 CFLAGS += -ffunction-sections -fdata-sections
 CFLAGS += -fshort-wchar -ffreestanding
@@ -173,7 +180,7 @@ DISTCLEAN_OBJS := $(shell find $(BASEDIR) -name '*.o')
 VERSION := bsp/$(PLATFORM)/include/bsp/version.h
 
 .PHONY: all
-all: $(VERSION) $(HV_OBJDIR)/$(HV_FILE).32.out $(HV_OBJDIR)/$(HV_FILE).bin
+all: $(BUILD_DEPS) $(VERSION) $(HV_OBJDIR)/$(HV_FILE).32.out $(HV_OBJDIR)/$(HV_FILE).bin
 	rm -f $(VERSION)
 
 ifeq ($(PLATFORM), uefi)

hypervisor/scripts/kconfig/kconfig.mk

@@ -0,0 +1,48 @@
+HV_CONFIG := .config
+HV_DEFCONFIG := defconfig
+HV_CONFIG_H := include/config.h
+HV_CONFIG_MK := include/config.mk
+
+KCONFIG_DIR := $(BASEDIR)/../scripts/kconfig
+
+$(eval $(call check_dep_exec,python))
+$(eval $(call check_dep_exec,pip))
+$(eval $(call check_dep_pylib,kconfiglib))
+
+# This target invoke silentoldconfig to generate a .config only if a .config
+# does not exist. Useful as a dependency for source compilation.
+$(HV_OBJDIR)/$(HV_CONFIG):
+	@mkdir -p $(HV_OBJDIR)
+	@python $(KCONFIG_DIR)/silentoldconfig.py Kconfig $(HV_OBJDIR)/$(HV_CONFIG) PLATFORM_$(shell echo $(PLATFORM) | tr a-z A-Z)=y
+
+$(HV_OBJDIR)/$(HV_CONFIG_MK): $(HV_OBJDIR)/$(HV_CONFIG)
+	@mkdir -p $(dir $@)
+	@cp $< $@
+
+$(HV_OBJDIR)/$(HV_CONFIG_H): $(HV_OBJDIR)/$(HV_CONFIG)
+	@mkdir -p $(dir $@)
+	@python $(KCONFIG_DIR)/generate_header.py Kconfig $< $@
+
+# This target forcefully generate a .config based on a given default
+# one. Overwrite the current .config if it exists.
+.PHONY: defconfig
+defconfig:
+	@mkdir -p $(HV_OBJDIR)
+	@python $(KCONFIG_DIR)/defconfig.py Kconfig arch/x86/configs/$(PLATFORM).config $(HV_OBJDIR)/$(HV_CONFIG)
+
+# Use silentoldconfig to forcefully update the current .config, or generate a
+# new one if no previous .config exists. This target can be used as a
+# prerequisite of all the others to make sure that the .config is consistent
+# even it has been modified manually before.
+.PHONY: oldconfig
+oldconfig:
+	@mkdir -p $(HV_OBJDIR)
+	@python $(KCONFIG_DIR)/silentoldconfig.py Kconfig $(HV_OBJDIR)/$(HV_CONFIG) PLATFORM_$(shell echo $(PLATFORM) | tr a-z A-Z)=y
+
+# Minimize the current .config. This target can be used to generate a defconfig
+# for future use.
+.PHONY: minimalconfig
+minimalconfig: $(HV_OBJDIR)/$(HV_CONFIG)
+	@python $(KCONFIG_DIR)/minimalconfig.py Kconfig $(HV_OBJDIR)/$(HV_CONFIG) $(HV_OBJDIR)/$(HV_DEFCONFIG)
+
+-include $(HV_OBJDIR)/$(HV_CONFIG_MK)