microsoft/openvmm

# guest_test_uefi

`guest_test_uefi` is a minimal `no_std` + `alloc` EFI application which hosts
a variety of OpenVMM-specific "bare metal" unit tests.

Want to write to an arbitrary MMIO/PIO address? Go for it! It's just you, the
VM, and the (very unobtrusive) UEFI runtime!

## Building + Running

`guest_test_uefi` must be built for `*-unknown-uefi` targets. These are not
installed by default, so you'll need to install the correct target via `rustup`.
For example:

```bash
rustup target add x86_64-unknown-uefi
```

Since this code runs in the guest, the built `.efi` binary needs to get packaged
into a disk image that UEFI can read.

To streamline the process of obtaining such a disk image, `cargo xtask` includes
a helper to generate properly formatted `.img` files containing a given `.efi`
image. e.g:

```bash
# build the UEFI test application
cargo build -p guest_test_uefi --target x86_64-unknown-uefi
# create the disk image
cargo xtask guest-test uefi --bootx64 ./target/x86_64-unknown-uefi/debug/guest_test_uefi.efi
# test in OpenVMM
cargo run -- --uefi --gfx --hv --processors 1 --disk memdiff:./target/x86_64-unknown-uefi/debug/guest_test_uefi.img
```

Protip: this is a generic UEFI binary, and can be run outside of the OpenVMM
repo as well (e.g: in QEMU, Hyper-V, etc...)!

To convert the raw `.img` into other formats, `qemu-img` is very helpful:

```bash
# Adjust for the target architecture and type of the build
OVMM_UEFI_TEST_IMG_DIR=./target/x86_64-unknown-uefi/debug
# VmWare
qemu-img convert -f raw -O vmdk ${OVMM_UEFI_TEST_IMG_DIR}/guest_test_uefi.img ${OVMM_UEFI_TEST_IMG_DIR}/guest_test_uefi.vmdk
# Hyper-V
qemu-img convert -f raw -O vhdx  ${OVMM_UEFI_TEST_IMG_DIR}/guest_test_uefi.img ${OVMM_UEFI_TEST_IMG_DIR}/guest_test_uefi.vhdx
# The files:
ls -la $OVMM_UEFI_TEST_IMG_DIR/{*.img,*.vhdx,*.vmdk}
```