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android / platform / packages / modules / Virtualization / 92199ced / . / microdroid
tree: b534c33f480c9658d803e2835a776a9407fe5f52 [path history] [tgz]
  1. signature/
  2. Android.bp
  3. build.prop
  4. dummy_dtb.img
  5. empty_kernel
  6. fstab
  7. init.rc
  8. linker.config.json
  9. microdroid_cdisk.json
  10. microdroid_cdisk_env.json
  11. microdroid_file_contexts
  12. microdroid_vendor_file_contexts
  13. plat_sepolicy_vers.txt
  14. README.md
  15. uboot-env-x86_64.txt
  16. uboot-env.txt
microdroid/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 install com.android.virt APEX. All files needed to run microdroid are included in the APEX, which is already in the yukawa (VIM3L) target. You can of course build and install the APEX manually.

$ source build/envsetup.sh
$ choosecombo 1 aosp_arm64 userdebug // actually, any arm64-based target is ok
$ m com.android.virt
$ adb install $ANDROID_PRODUCT_OUT/system/apex/com.android.virt.apex
$ adb reboot

Running

Copy the artifacts to the temp directory, create the composite image using mk_cdisk, and run it via crosvm. For now, some other files have to be manually created. In the future, you won't need these, and this shall be done via virtmanager.

$ adb shell 'cp /apex/com.android.virt/etc/microdroid_bootloader /data/local/tmp/bootloader'
$ adb shell 'cp /apex/com.android.virt/etc/fs/*.img /data/local/tmp'
$ adb shell 'cp /apex/com.android.virt/etc/uboot_env.img /data/local/tmp'
$ adb shell 'dd if=/dev/zero of=/data/local/tmp/misc.img bs=4k count=256'
$ adb shell 'cd /data/local/tmp; /apex/com.android.virt/bin/mk_cdisk /apex/com.android.virt/etc/microdroid_cdisk.json os_composite.img'
$ adb shell 'cd /data/local/tmp; /apex/com.android.virt/bin/mk_cdisk /apex/com.android.virt/etc/microdroid_cdisk_env.json env_composite.img'
$ adb shell 'cd /data/local/tmp; /apex/com.android.virt/bin/crosvm run --cid=5 --disable-sandbox --bios=bootloader --serial=type=stdout --disk=os_composite.img --disk=env_composite.img'

The CID in --cid parameter can be anything greater than 2 (VMADDR_CID_HOST).

ADB

$ adb forward tcp:8000 vsock:5:5555
$ adb connect localhost:8000

5 in vsock:5 should match with the CID number that was given to crosvm. 5555 must be the value. 8000 however can be any port in the development machine.

Done. Now you can log into microdroid. Have fun!

$ adb -s localhost:8000 shell