README

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This repository contains command-line tools and kernel modules associated with hvisor. The command-line tools also include the Virtio daemon, which provides Virtio devices. The command-line tools and kernel modules need to be compiled separately and used in the root Linux zone0 of the virtual machine manager. The structure of the repository is as follows:

hvisor-tool
	-tools: Contains command-line tools and the Virtio daemon
	-driver: Kernel module corresponding to hvisor

Compilation Steps

The following operations are performed under the hvisor-tool directory on an x86 host for cross-compilation.

• Compile command-line tools and kernel modules

make all ARCH=<arch> LOG=<log> KDIR=/path/to/your-linux 

Where <arch> should be one of arm64 or riscv.

<log> can be one of LOG_TRACE, LOG_DEBUG, LOG_INFO, LOG_WARN, LOG_ERROR, or LOG_FATAL, which controls the log level of the Virtio daemon.

/path/to/your-linux is the kernel source directory for root Linux. For specific compilation options, refer to the Makefile, tools/Makefile, and driver/Makefile.

For example, to compile command-line tools for arm64, you can run:

make all ARCH=arm64 LOG=LOG_WARN KDIR=~/linux

This will generate the tools/hvisor binary and driver/hvisor.ko module, which can be copied to the root Linux file system for use.

Usage Steps

Kernel Module

Before using the command-line tools and Virtio daemon, you need to load the kernel module on zone0 to enable interaction between user-space programs and the hypervisor:

insmod hvisor.ko

To unload the kernel module, use the following command:

rmmod hvisor.ko

Command-Line Tools

In root Linux-zone0, the command-line tool can be used to create and shut down other virtual machines.

• Start a new virtual machine

  hvisor-tool can start a new virtual machine using a configuration file:

  ./hvisor zone start <vm_config.json>
  

  <vm_config.json> is a file that describes the configuration of a virtual machine. For example:

  • Start zone1 on QEMU-aarch64: When using this file to directly start zone1, you must first start the Virtio daemon, with the corresponding configuration file being virtio_cfg.json.

  • Start zone1 on NXP-aarch64: Similar to the QEMU example, first start the Virtio daemon with virtio_cfg.json.

• To shut down a virtual machine with ID 1:

./hvisor zone shutdown -id 1

• To list all currently running virtual machines:

./hvisor zone list

Virtio Daemon

The Virtio daemon provides Virtio MMIO devices for virtual machines. Currently, it supports three types of devices: Virtio-blk, Virtio-net, and Virtio-console.

Prerequisites

To use the Virtio daemon, a node named hvisor_device must be added to the device tree of Root Linux, for example:

hvisor_device {
    compatible = "hvisor";
    interrupt-parent = <0x01>;
    interrupts = <0x00 0x20 0x01>;
};

This ensures that when the hypervisor injects interrupt number 32+0x20 into Root Linux, the interrupt handler registered in hvisor.ko will be invoked, waking up the Virtio daemon.

Starting and Creating Virtio Devices

On Root Linux, execute the following example commands:

// Ensure the daemon is started before launching the zones
nohup ./hvisor virtio start virtio_cfg.json &
./hvisor zone start <vm_config.json>

The command nohup ... & starts a daemon process, with its log output saved to the nohup.out file in the current directory.

virtio_cfg.json is a JSON file that describes Virtio devices, such as virtio_cfg.json. This example file performs the following steps:

1. Address space mapping

Maps the RAM region of virtual machine zone1 (ID 1) (starting at address 0x50000000, size 0x30000000) into the Virtio daemon's address space using mmap.

2. Create Virtio-blk device

Creates a Virtio-blk device, with zone1 communicating with this device through an MMIO region starting at 0xa003c00 and a length of 0x200. The device interrupt number is set to 78, and the disk image used is rootfs2.ext4.

3. Create Virtio-console device

Creates a Virtio-console device for zone1's primary serial output. Root Linux can access this virtual console using the screen /dev/pts/x command, where x can be found in the nohup.out log file.

To return to the main console, press the shortcut ctrl+a+d. To re-enter the virtual console, run screen -r [SID], where SID is the screen session ID.

4. Create Virtio-net device

Since the status attribute of the net device is set to disable, a Virtio-net device is not created. If the status attribute is set to enable, a Virtio-net device would be created with an MMIO region starting at 0xa003600, length 0x200, interrupt number 75, and MAC address 00:16:3e:10:10:10, which would be used by the virtual machine with ID 1 and connected to the tap0 Tap device.

Shutting Down Virtio Devices

To shut down the Virtio daemon and all created devices, run the following command:

pkill hvisor-virtio

For more information, such as configuring the root Linux environment, refer to: Using Virtio Devices on hvisor.