From 217ea254876e84fead5624780b4ecde40fe690df Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andrius=20=C5=A0tikonas?= <andrius@stikonas.eu>
Date: Sun, 7 Aug 2022 12:23:00 +0100
Subject: [PATCH] Add a short README.

---
 Makefile  |  5 ++++-
 README.md | 22 ++++++++++++++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 README.md

diff --git a/Makefile b/Makefile
index 65fc360..9e8aff8 100644
--- a/Makefile
+++ b/Makefile
@@ -2,7 +2,6 @@
 #
 # SPDX-License-Identifier: GPL-3.0-or-later
 
-targets = kaem-minimal hex0
 ESP_SIZE_MIB = 50
 QEMU = qemu-system-x86_64
 QEMU_KVM = -enable-kvm
@@ -47,7 +46,11 @@ rootfs:
 
 	mkdir -p $(rootfs_dir)/bootstrap-seeds/UEFI/
 	rsync -av bootstrap-seeds/UEFI/ $(rootfs_dir)/bootstrap-seeds/UEFI/
+ifndef MINIMAL
 	mv $(rootfs_dir)/bootstrap-seeds/UEFI/amd64/kaem-optional-seed.efi $(boot_dir)/BOOTX64.efi
+else
+	rm $(rootfs_dir)/bootstrap-seeds/UEFI/amd64/kaem-optional-seed.efi
+endif
 
 clean:
 	rm -rf $(build_dir)
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..f17cc1e
--- /dev/null
+++ b/README.md
@@ -0,0 +1,22 @@
+# stage0-uefi
+
+This is a port of stage0-posix (https://github.com/oriansj/stage0-posix) to UEFI.
+
+## Usage
+
+`make build/disk.img` will create bootable images with stage0-uefi. You can use `dd` to write them on bootable media.
+
+`make qemu` will create disk image and launch it in QEMU. To test this in QEMU, you need to provide some QEMU compatible UEFI implementation. In particular, you can use Tianocore's OVMF. `make qemu` is looking for it in a few paths where distros tend to install it. If not you can specify it via `make qemu OVMF_IMG=/path/to/OVMF_CODE.fd`
+
+## Minimal images
+
+It is possible to create images without `kaem-optional-seed.efi` that contain only `hex0-seed.efi`. Those are a bit less automated but if your UEFI implementation lets you to pass command line arguments, you can recreate kaem using just hex0.
+
+- `make MINIMAL=1 qemu`.
+- Open UEFI settings (often F2 but it varies from system to system).
+- Go to `Add Boot option` and pick appropriate boot volume that contains `hex0-seed.efi`.
+- Pick `\bootstrap-seeds\UEFI\amd64\hex0-seed.efi`.
+- Description can be anything, say `kaem-seed`.
+- Optional Data has to be `hex0 amd64\kaem-minimal.hex0 EFI\BOOT\BOOTX64.efi`.
+- Save boot entry and boot it. This will build kaem-minimal and exit.
+- Now boot normally from bootable media.