Configuration and Management of Zones

The hvisor project, as a lightweight hypervisor, uses a Type-1 architecture that allows multiple virtual machines (zones) to run directly on top of hardware. Below is a detailed explanation of the key points for zone configuration and management:

Resource Allocation

Resources such as CPU, memory, devices, and interrupts are statically allocated to each zone, meaning that once allocated, these resources are not dynamically scheduled between zones.

Root Zone Configuration

The configuration of the root zone is hardcoded within hvisor, written in Rust, and represented as a C-style structure HvZoneConfig. This structure contains key information such as zone ID, number of CPUs, memory regions, interrupt information, physical addresses and sizes of the kernel and device tree binary (DTB).

Non-root Zones Configuration

The configuration of non-root zones is stored in the root Linux file system, usually represented in JSON format. For example:

    {
        "arch": "arm64",
        "zone_id": 1,
        "cpus": [2, 3],
        "memory_regions": [
            {
                "type": "ram",
                "physical_start": "0x50000000",
                "virtual_start":  "0x50000000",
                "size": "0x30000000"
            },
            {
                "type": "io",
                "physical_start": "0x30a60000",
                "virtual_start":  "0x30a60000",
                "size": "0x1000"
            },
            {
                "type": "virtio",
                "physical_start": "0xa003c00",
                "virtual_start":  "0xa003c00",
                "size": "0x200"
            }
        ],
        "interrupts": [61, 75, 76, 78],
        "kernel_filepath": "./Image",
        "dtb_filepath": "./linux2.dtb",
        "kernel_load_paddr": "0x50400000",
        "dtb_load_paddr":   "0x50000000",
        "entry_point":      "0x50400000"
    }

• The arch field specifies the target architecture (e.g., arm64).
• cpus is a list that indicates the CPU core IDs allocated to the zone.
• memory_regions describe different types of memory regions and their physical and virtual start addresses and sizes.
• interrupts list the interrupt numbers allocated to the zone.
• kernel_filepath and dtb_filepath indicate the paths of the kernel and device tree binary files, respectively.
• kernel_load_paddr and dtb_load_paddr are the physical memory load addresses for the kernel and device tree binary.
• entry_point specifies the kernel's entry point address.

The management tool of root Linux is responsible for reading the JSON configuration file and converting it into a C-style structure, which is then passed to hvisor to start the non-root zones.