4d43cbb0c6
microdroid_vendor implements the vendor.img of microdroid. In theory, microdroid doesn't need a vendor partition as it by definition isn't specific to any SoC. However, init demands some files from the vendor partition during the boot process. Until we find a way to make the dependencies optional, let's have the vendor partition. Fortunately, it is very small. It currently has a few number of sepolicy files only. Bug: 180986662 Test: run microdroid following README.md init enters into the second stage, sepolicy files are compiled, init tries to start the servicemanager (which fails) Change-Id: I82a66a00a8680ef1070ae7313d8e326f3ebc3112 |
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|---|---|---|
| .. | ||
| Android.bp | ||
| README.md | ||
| dummy_dtb.img | ||
| fstab | ||
| init.rc | ||
| microdroid.pem | ||
| microdroid_file_contexts | ||
| microdroid_vendor_file_contexts | ||
| plat_sepolicy_vers.txt | ||
| uboot-env.txt | ||
README.md
Microdroid
Microdroid is a (very) lightweight version of Android that is intended to run on on-device virtual machines. It is built from the same source code as the regular Android, but it is much smaller; no system server, no HALs, no GUI, etc. It is intended to host headless & native workloads only.
Building
You need a VIM3L board. Instructions for building Android for the target, and flashing the image can be found here.
Then you build microdroid. Note that the instruction below is very likely to
change in the future, because this is in active development. For example, the
microdroid_* modules will eventually be included in the com.android.virt
APEX, which is already in the yukawa (VIM3L) target.
$ source build/envsetup.sh
$ choosecombo 1 aosp_arm64 userdebug // actually, any arm64-based target is ok
$ m microdroid_super
$ m microdroid_boot-5.10
$ m microdroid_vendor_boot-5.10
$ m microdroid_uboot_env
Installing
Push the built files to the device. In addition to that, some other files have to be manually created, for now. In the future, you won't need these.
$ adb push device/google/cuttlefish_prebuilts/bootloader/crosvm_aarch64/u-boot.bin /data/local/tmp/bootloader
$ adb push $ANDROID_PRODUCT_OUT/system/etc/microdroid_super.img /data/local/tmp/super.img
$ adb push $ANDROID_PRODUCT_OUT/system/etc/microdroid_boot-5.10.img /data/local/tmp/boot.img
$ adb push $ANDROID_PRODUCT_OUT/system/etc/microdroid_vendor_boot-5.10.img /data/local/tmp/vendor_boot.img
$ adb shell mkdir /data/local/tmp/cuttlefish_runtime.1/
$ adb push $ANDROID_PRODUCT_OUT/system/etc/uboot_env.img /data/local/tmp/cuttlefish_runtime.1/
$ adb shell mkdir -p /data/local/tmp/etc/cvd_config
$ adb shell 'echo "{}" > /data/local/tmp/etc/cvd_config/cvd_config_phone.json'
$ dd if=/dev/zero of=empty.img bs=4k count=600
$ mkfs.ext4 -F empty.img
$ adb push empty.img /data/local/tmp/userdata.img
$ adb push empty.img /data/local/tmp/vbmeta.img
$ adb push empty.img /data/local/tmp/vbmeta_system.img
$ adb push empty.img /data/local/tmp/cache.img
Running
Create the composite image using assemble_cvd and run it via crosvm. In the
future, this shall be done via virtmanager.
$ adb shell 'HOME=/data/local/tmp; /apex/com.android.virt/bin/assemble_cvd < /dev/null'
$ adb shell 'cd /data/local/tmp; /apex/com.android.virt/bin/crosvm run --disable-sandbox --bios=bootloader --serial=type=stdout --disk=cuttlefish_runtime/composite.img'
At this moment, this doesn't boot to the shell, but to the second-stage init.