Dumping VMs with bugreport

On adb bugreport (or dumpsys android.system.virtualizationservice), virtualizationservice dumps basic information of running VMs.

vsoc_x86_64:/ # dumpsys android.system.virtualizationservice
Running 1 VMs:
VM CID: 2048
    name: VmRunApp
    temporary_directory: /data/misc/virtualizationservice/2048
    requester_uid: 2000
    requester_debug_pid: 26649
    VM dump begin
    (VM dump contents...)
    VM dump end

Implement Detailed VM Dump

In addition to basic information, guest OSes can implement IGuestAgent's startDumpVsockServer method to dump detailed internal state of VMs.

int startDumpVsockServer(in String[] args);

When startDumpVsockServer is called, the guest agent should:

1. Start a vsock server: Open a vsock server and listen for an incoming connection.
2. Dump VM state: Upon a client connection (from virtualizationservice), the guest OS must write dump to the connected vsock stream.
3. Timeout: The entire dumping process (including writing to the vsock) should complete within 5 seconds. virtualizationservice may otherwise consider it a timeout.

virtualizationservice then embeds this detailed dump directly into the adb bugreport output.

Microdroid's VM Dump Implementation

The guest agent in microdroid_manager implements basic dump for Microdroid VMs, focusing on memory and process-related statistics. The dump includes the contents of the following files:

• /proc/meminfo
• /proc/pressure/*
• /sys/fs/cgroup/*/memory.* (excluding memory.reclaim)
• /proc/*/smaps_rollup
• /proc/pagetypeinfo
• /proc/vmstat
• /proc/zoneinfo
• /proc/*/smaps (debuggable VMs only)