RustyLoader

RustyLoader is a loader to run RustyHermit within QEMU.

Requirements

rustup
NASM (only for x86_64)

Building

$ cargo xtask build --target <TARGET> --release

With <TARGET> being either x86_64, x86_64-uefi, or aarch64.

Afterward, the loader is located at target/<TARGET>/release/rusty-loader.

Running

Boot a hermit application:

$ qemu-system-x86_64 \
    -cpu qemu64,apic,fsgsbase,fxsr,rdrand,rdtscp,xsave,xsaveopt \
    -smp 1 -m 64M \
    -device isa-debug-exit,iobase=0xf4,iosize=0x04 \
    -display none -serial stdio \
    -kernel <LOADER> \
    -initrd <APP>

Arguments can be provided like this:

$ qemu-system-x86_64 ... \
    -append "[KERNEL_ARGS] [--] [APP_ARGS]"

On AArch64, the base command is as follows:

$ qemu-system-aarch64 \
                  -machine virt,gic-version=3 \
                  -cpu cortex-a76 -smp 1 -m 512M  \
                  -semihosting \
                  -display none -serial stdio \
                  -kernel <LOADER> \
                  -device guest-loader,addr=0x48000000,initrd=<APP>

Using QEMU as microvm

QEMU provides the microvm virtual platform, which is a minimalist machine type without PCI nor ACPI support. Microvms have a smaller memory footprint and a faster boot time.

To use this VM type, PCI and ACPI support have to be disabled for your app (using no-default-features).

$ qemu-system-x86_64 ... \
    -M microvm,x-option-roms=off,pit=off,pic=off,rtc=on,auto-kernel-cmdline=off \
    -nodefaults -no-user-config \
    -append "-freq 2800"

Depending on the virtualized processor, the processor frequency has to be passed as kernel argument (-freq, in MHz).

Network support

To enable an Ethernet device, we have to set up a tap device on the host system. The following commands establish the tap device tap10 on Linux:

# ip tuntap add tap10 mode tap
# ip addr add 10.0.5.1/24 broadcast 10.0.5.255 dev tap10
# ip link set dev tap10 up
# echo 1 > /proc/sys/net/ipv4/conf/tap10/proxy_arp

If you want Hermit to be accessible from outside the host, you have to enable IP forwarding:

# sysctl -w net.ipv4.ip_forward=1

You need to enable the tcp feature of the kernel.

The network configuration can be set via environment variables during compile time. By default, it is:

HERMIT_IP="10.0.5.3"
HERMIT_GATEWAY="10.0.5.1"
HERMIT_MASK="255.255.255.0"

Currently, Hermit only supports Virtio:

$ qemu-system-x86_64 ... \
    -netdev tap,id=net0,ifname=tap10,script=no,downscript=no,vhost=on \
    -device virtio-net-pci,netdev=net0,disable-legacy=on

You can now access the files in SHARED_DIRECTORY under the virtiofs tag like /myfs/testfile.

License

Licensed under either of

Apache License, Version 2.0, (LICENSE-APACHE or http://www.apache.org/licenses/LICENSE-2.0)
MIT license (LICENSE-MIT or http://opensource.org/licenses/MIT)

at your option.

hermitcore / rusty-loader