README: Update to reflect current functionality and usage

Signed-off-by: Rob Bradford <[email protected]>

Author: rbradford

README.md

@@ -1,21 +1,25 @@
-# Simple KVM firmware
+# Rust Hypervisor Firmware
 
-**This project is an experiment and should not be used production workloads.**
+This repository contains a simple firmware that is designed to be launched from
+anything that supports loading ELF binaries and running them with the
+PVH booting standard
 
-This repository contains a simple KVM firmware that is designed to be launched
-from anything that supports loading ELF binaries and running them with the
-Linux kernel loading standard.
-
-The ultimate goal is to be able to use this "firmware" to be able to load a
-bootloader from within a disk image.
+The purpose is to be able to use this firmware to be able to load a
+bootloader from within a disk image without requiring the use of a complex
+firmware such as TianoCore/edk2 and without requiring the VMM to reuse
+functionality used for booting the Linux kernel.
 
 Currently it will directly load a kernel from a disk image that follows the
 [Boot Loader Specification](https://systemd.io/BOOT_LOADER_SPECIFICATION)
 
+There is also minimal EFI compatibility support allowing the boot of some
+images that use EFI (shim + GRUB2 as used by Ubuntu).
+
 The firmware is primarily developed against [Cloud
-Hypervisor](https://github.com/intel/cloud-hypervisor).
+Hypervisor](https://github.com/cloud-hypervisor/cloud-hypervisor) but there is
+also support for using QEMU's PVH loader.
 
-This project was orginally developed using
+This project was originally developed using
 [Firecracker](https://github.com/firecracker-microvm) however as it does not
 currently support resetting the virtio block device it is not possible to boot
 all the way into the OS.
@@ -32,7 +36,7 @@ target/target/release/hypervisor-fw
 
 ## Features
 
-* virtio (MMIO & PCI) block support
+* virtio (PCI) block support
 * GPT parsing (to find EFI system partition)
 * FAT12/16/32 directory traversal and file reading
 * bzImage loader
@@ -42,17 +46,16 @@ target/target/release/hypervisor-fw
 
 ## Running
 
-Works with Cloud Hypervisor and Firecracker as a drop in replacement for the
-Linux kernel. It does not work with crosvm as crosvm has a hardcoded kernel
-function start address.
+Works with Cloud Hypervisor and QEMU via their PVH loaders as an alternative to
+the Linux kernel.
 
-Cloud Hypervisor is currently the primary development target for the firmware
-although support for other VMMs will be considered.
+Cloud Hypervisor and QEMU are currently the primary development targets for the
+firmware although support for other VMMs will be considered.
 
 ### Cloud Hypervisor
 
 As per [getting
-started](https://github.com/intel/cloud-hypervisor/blob/master/README.md#2-getting-started)
+started](https://github.com/cloud-hypervisor/cloud-hypervisor/blob/master/README.md#2-getting-started)
 
 However instead of using the binary firmware for the parameter to `--kernel`
 instead use the binary you build above.
@@ -62,57 +65,29 @@ $ pushd $CLOUDH
 $ sudo setcap cap_net_admin+ep ./cloud-hypervisor/target/release/cloud-hypervisor
 $ ./cloud-hypervisor/target/release/cloud-hypervisor \
 	--kernel ./target/target/release/hypervisor-fw \
-	--disk path=./clear-29160-kvm.img \
+	--disk path=focal-server-cloudimg-amd64.raw \
 	--cpus boot=4 \
 	--memory size=512M \
 	--net "tap=,mac=,ip=,mask=" \
 	--rng
 $ popd
 ```
 
-### Firecracker
+### QEMU
 
-As per [quick
-start](https://github.com/firecracker-microvm/firecracker/blob/master/docs/getting-started.md)
+Use the QEMU `-kernel` parameter to specify the path to the firmware.
 
-Replacing the kernel and rootfs to point at the firmware and the full disk
-image instead.
+e.g.
 
 ```
-curl --unix-socket /tmp/firecracker.socket -i \
-    -X PUT 'http://localhost/boot-source'   \
-    -H 'Accept: application/json'           \
-    -H 'Content-Type: application/json'     \
-    -d '{
-        "kernel_image_path": "target/target/release/hypervisor-fw",
-        "boot_args": ""
-    }'
-
-curl --unix-socket /tmp/firecracker.socket -i \
-    -X PUT 'http://localhost/drives/rootfs' \
-    -H 'Accept: application/json'           \
-    -H 'Content-Type: application/json'     \
-    -d '{
-        "drive_id": "rootfs",
-        "path_on_host": "clear-28660-kvm.img",
-        "is_root_device": true,
-        "is_read_only": false
-    }'
-
-curl --unix-socket /tmp/firecracker.socket -i \
-    -X PUT 'http://localhost/actions'       \
-    -H  'Accept: application/json'          \
-    -H  'Content-Type: application/json'    \
-    -d '{
-        "action_type": "InstanceStart"
-     }'
-
+$ qemu-system-x86_64 -machine q35,accel=kvm -cpu host,-vmx -m 1G\
+    -kernel ./target/target/release/hypervisor-fw \
+    -display none -nodefaults \
+    -serial stdio \
+    -drive id=os,file=focal-server-cloudimg-amd64.raw,if=none \
+    -device virtio-blk-pci,drive=os,disable-legacy=on
 ```
 
-**Currently Firecracker's virtio block device does not support resetting the
-device and as such it is not possible for the booted Linux kernel to take over
-the device from the firmware.**
-
 ## Testing
 
 "cargo test" needs disk images from make-test-disks.sh
@@ -122,28 +97,3 @@ And clear-28660-kvm.img:
 https://download.clearlinux.org/releases/28660/clear/clear-28660-kvm.img.xz
 
 sha1sum: 5fc086643dea4b20c59a795a262e0d2400fab15f
-
-## Security
-
-**Reporting a Potential Security Vulnerability**: If you have discovered
-potential security vulnerability in this project, please send an e-mail to
-[email protected]. For issues related to Intel Products, please visit
-https://security-center.intel.com.
-
-It is important to include the following details:
-  - The projects and versions affected
-  - Detailed description of the vulnerability
-  - Information on known exploits
-
-Vulnerability information is extremely sensitive. Please encrypt all security
-vulnerability reports using our *PGP key*
-
-A member of the Intel Product Security Team will review your e-mail and
-contact you to to collaborate on resolving the issue. For more information on
-how Intel works to resolve security issues, see: *Vulnerability Handling
-Guidelines*
-
-PGP Key: https://www.intel.com/content/www/us/en/security-center/pgp-public-key.html
-
-Vulnerability Handling Guidelines: https://www.intel.com/content/www/us/en/security-center/vulnerability-handling-guidelines.html
-