Introduce
==========

Hyper-gen is a new generation hypervisor with high-efficient architecture design and small codesize.
Based on qemu-kvm and linux kernel, by reshuffling the architecture and leaving only most useful code, hyper-gen is purpose to support the three kinds of VM instance as below:
a. lightweight VM
   exclude emulation of firmware and unnecessary devices.
b. baremetal VM
   with lapic passthrough and other VT optimizations, reduce VM-EXITs to minimal.
c. normal VM
   support all the virtualization features such as firmware, vgpu, migration, hotplug to run any kind of guestOS.

For now, hyper-gen only supports lightweight VM instance and Intel IA CPUs.
The following is the main architecture of hyper-gen.


|---------------------------------------|
|non-root  |                            |
|----------                             |
|                                       |
|      VM0  VM1  VM2  ...  VMn          |
|                                       |
|---------------------------------------|
|root&ring0 |                           |
|-----------                            |
|      a. reshuffled tiny-kernel        |
|      b. qemu-mini                     |
|      c. customized KVM module         |
|      d. hyper-gen shell               |
|---------------------------------------|
|         Hardware                      |
|---------------------------------------|




Getting Started
================

1. First of all, you should have a linux host such as ubuntu, centos or any other linux distribution.

2. Building hyper-gen is the same as kernel, except the config file as follows:
     git clone  https://github.com/zgen0623/hyper-gen.git
     cd hyper-gen
     mkdir out
     cp config_tiny_kernel out/.config
     make bzImage O=./out

3. Install hyper-gen as follows:
     copy bzImage file to /boot/ directory
     edit the menuentry in /boot/grub/grub.cfg and replace the kernel image with the new bzImage as below
        linux   /boot/vmlinuz-5.4.0-48-generic root=/dev/mapper/ubuntu--vg-root
          to
        linux   /boot/bzImage root=/dev/mapper/ubuntu--vg-root

4. Create a directory for saving decompressed kernel images(vmlinux) and update the kernel cmdline as follows:
     mkdir /path/to/guest_kernel
     edit the menuentry in /boot/grub/grub.cfg as below
        linux   /boot/bzImage root=/dev/mapper/ubuntu--vg-root guest_kernel=/path/to/guest_kernel

5. Prepare a normal kernel codebase, build a decompressed kernel image file vmlinux and save it in /path/to/guest_kernel.

6. Create a directory for saving raw format qemu rootfs images and update the kernel cmdline as follows:
     mkdir /path/to/guest_image
     edit the menuentry in /boot/grub/grub.cfg as below
        linux   /boot/bzImage root=/dev/mapper/ubuntu--vg-root guest_kernel=/path/to/guest_kernel guest_image=/path/to/guest_image

7. Make a raw format rootfs image, and save it in /path/to/guest_image

8. Reboot and select the menuentry for hyper-gen in grub bootmenu 

9. Press ALT+F3 into hyper-gen shell

10. Shell commands for hyper-gen
   image_list: list all the rootfs images
   kernel_list: list all the kernel images
   vm_list: list all the running VMs
   vm_create <kernel id> <image id>: create a VM
   vm_destroy <vm id>:  detroy a VM
   vm_console <vm id>:  attach to a VM console    // press CTRL+d to deattach




Planned features
================
Host:
    reshuffle kernel mm to apply hugepage
    dynamic lapic passthrough

Virtualization:
    pt dev
    9p
    uefi virtualization
    vgpu
    migration
    hotplug

Management:
    manager VM
    hyper-gen proxy module in manager VM
    libvirt for hyper-gen