1# Prebuilts
2
3## How to update
4
5From your AOSP repo:
6
7```
8./device/google/cuttlefish_vmm/rebuild.sh \
9  --docker \
10  --docker_arch aarch64
11```
12
13If you need to make edits and iterate afterward:
14
15./device/google/cuttlefish_vmm/rebuild.sh \
16  --docker \
17  --docker_arch aarch64 \
18  --reuse
19```
20
21## Why do we need these?
22
23The Android toolchain builds the Cuttlefish host tools for ARM using musl
24which is not compatible with most userspace GPU drivers which are built
25using glibc (see b/200592498).
26
27The vhost-user protocol allows VMMs to run individual virtual devices in
28separate host processes. By using vhost-user-gpu, the Cuttlefish host tools
29can run just the Virtio GPU device in a separate subprocess using a Crosvm
30binary and Gfxstream library built for the host architecture. This directory
31contains prebuilts for Crosvm and Gfxstream for this purpose.
32