Android Emulator M1 Preview

Note: There is an official repo now which is preferred: (https://github.com/google/android-emulator-m1-preview). We will still watch this repo for issues and comments, but please redirect your activity to the official repo.

This is a preview of some basic Android emulation functionality on the M1. There are still many issues, but apps work at a basic level. To be updated soon with more fixes. The release tag corresponds to this commit: https://android.googlesource.com/platform/external/qemu/+/aca144a9e9264b11c2d729096af90d695d01455d

Known issues

• Webview doesn't work
• No device skins
• Video codecs not working
• 32 bit ARM apps won't work
• Graphical glitches in some Vulkan apps
• Popup on startup about not being able to find the ADB path (ADB will still notice the emulator if you have it installed though)
• When building, it may be faster to start then cancel the Python triggered build and then reissue ninja -C objs install/strip versus letting the Python triggered build finish.

How to use

This only works on M1 Apple Silicon Macs. M1 (or equivalently capable) SoCs are required; note that this does not work on DTKs as they do not support ARM64 on ARM64 hardwre virtualization via Hypevisor.framework.

Go to the Github releases page, download a .dmg, drag to the Applications folder, and run. You'll first need to right click the app icon and select Open and then skip past the developer identity verification step (we are working on providing official identity info). The first few times it starts up it will take a while to show up, but subsequent launches will be faster.

If you've installed Android Studio and Android SDK and adb is available, the emulator should be visible from Studio and work (deploy built apps, debug apps, etc).

How to configure

Edit /Applications/Android\ Emulator.app/Contents/MacOS/aosp-master-arm64-v8a/config.ini. Some notable options:

• disk.dataPartition.size: size of userdata. When reconfiguring, you'll also need to delete all userdata*.img files in that directory.
• fastboot.forceColdBoot,fastboot.forceFastBoot: whether to enable snapshots. Current default is snapshots disabled. Set fastboot.forceColdBoot=no,fastboot.forceFastBoot=yes to enable snapshots.
• hw.lcd.density: Virtual display DPI.
• hw.lcd.width,hw.lcd.height: Virtual display dimensions.
• hw.ramSize: RAM limit for the guest. (2GB minimum)

How to wipe data

Remove all userdata*.img files in /Applications/Android\ Emulator.app/Contents/MacOS/aosp-master-arm64-v8a/.

How to build your own emulator

Building the engine

The emulator source code lives (here), but there are a bunch of other dependencies to download, so we use repo.

To build, first make sure you have Xcode and Xcode command line tools installed, and that you have Chromium depot_tools in your PATH (link). Then:

mkdir emu
cd emu
repo init -u https://android.googlesource.com/platform/external/qemu --depth=1
repo sync -qcj 4
cd external/qemu
python android/build/python/cmake.py --target=darwin_aarch64

Note that canceling the python based build after it gets going and issuing just ninja -C objs install/strip may be faster.

The built artifacts are in /path/to/external/qemu/objs/distribution/emulator. They should be automatically signed. However, the binaries in objs/ are not; to sign them, issue ./sign-objs-binaries.sh. Note that this can only be done after ninja -C objs install/strip is successful.

Building the system image

The system image is built from AOSP master sdk_phone_arm64 with a few modifications. Ideally, let's be on a Linux host when building the system image---the build is relatively untested on M1 systems, and at least, we need to create a separate case sensitive partition for the AOSP repo. Assuming you're on Linux:

mkdir aosp-master
cd aosp-master
repo init -u https://android.googlesource.com/platform/manifest -b master --depth=1
repo sync -qcj 4

We first need to make an edit to remove all 32 bit support. Patch this change: link to build/make/target/board/emulator_arm64/BoardConfig.mk. Then:

source build/envsetup.sh
lunch sdk_phone_arm64-userdebug
make -j12

After that's done, we can use this script to package up the system image for use in /Applications/Android\ Emulator.app/Contents/MacOS/aosp-master-arm64-v8a/. Assuming you're still in the Android build environment:

echo $ANDROID_PRODUCT_OUT
export ZIPPED_NAME=$1
mkdir -p $ZIPPED_NAME/files
cd $ZIPPED_NAME/files
cp $ANDROID_PRODUCT_OUT/system-qemu.img system.img
cp $ANDROID_PRODUCT_OUT/vendor.img vendor.img
cp $ANDROID_PRODUCT_OUT/ramdisk.img ramdisk.img
cp $ANDROID_PRODUCT_OUT/ramdisk.img ramdisk.img
if [ -f $ANDROID_PRODUCT_OUT/kernel-ranchu-64 ]; then
    cp $ANDROID_PRODUCT_OUT/kernel-ranchu-64 kernel-ranchu-64
else
    cp $ANDROID_PRODUCT_OUT/kernel-ranchu kernel-ranchu
fi;
cp -r $ANDROID_PRODUCT_OUT/data .
cp -r $ANDROID_PRODUCT_OUT/advancedFeatures.ini advancedFeatures.ini
cp -r $ANDROID_PRODUCT_OUT/userdata.img .
cp -r $ANDROID_PRODUCT_OUT/encryptionkey.img .
cp -r $ANDROID_PRODUCT_OUT/build.prop .
mkdir system
cp -r $ANDROID_PRODUCT_OUT/build.prop system/build.prop
cp -r $ANDROID_PRODUCT_OUT/VerifiedBootParams.textproto .
cp -r $ANDROID_PRODUCT_OUT/source.properties .

cd ..
zip -1rq $ZIPPED_NAME.zip files
ls -l $ZIPPED_NAME.zip

Then, $ZIPPED_NAME.zip can be sent over to the M1 and the contents of its files/ can be coped over into /Applications/Android\ Emulator.app/Contents/MacOS/aosp-master-arm64-v8a/.