RISC-V Hypervisors

NOTE: Xvisor run "fails" due to timeout since Xvisor is never shutdown after Linux successfully exits. This issue probably won't be solved due to time constraints. Nevertheless, the job is left enabled since manual inspection of the logs still provides relevant information about the simulation.

The main reason this repository exist is to build binaries for testing hypervisor extension support in the RISC-V Sail model. There are two different targets:

• An image with linux directly on top of the openSBI firmware
• An image with linux as guest OS in Xvisor on top of the openSBI firmware

Getting started - Docker

Prebuild images are available with the spike emulator and the Sail extracted C emulator:

	Linux	Xvisor
Spike	linux-spike	xvisor-spike
CSim	linux-csim	xvisor-csim

These images can be used in similar fashion as the following xvisor-csim example.

$ docker run --rm --name wip -it ghcr.io/defermelowie/riscv-hext-xvisor-linux/xvisor-csim:wip

root@1a3a7c7bc7ce:/hyp# echo "autoexec" | ./sim/sail/c_emulator/riscv_sim_RV64 -Vmem -Vplatform -Vreg -Vinstr --enable-dirty-update --enable-pmp --mtval-has-illegal-inst-bits --xtinst-has-transformed-inst --ram-size 1024 --device-tree-blob rv64gch_xvisor.dtb opensbi_xvisor_payload.elf

...

Getting started - Local

Initial setup

Checkout git submodules:

git submodule update --init

Create target directory:

mkdir target

Linux

Create device files (can't be tracked by git)

sudo mknod -m 666 initramfs/dev/null c 1 3

sudo mknod -m 600 initramfs/dev/console c 5 1

Update path of initramfs to embed in linux kernel

First get the new path:

echo $(pwd)/target/initramfs.cpio

Next, update linux-sail-64b_defconfig

 CONFIG_NAMESPACES=y
 CONFIG_USER_NS=y
 CONFIG_CHECKPOINT_RESTORE=y
 CONFIG_BLK_DEV_INITRD=y
-CONFIG_INITRAMFS_SOURCE="old_initramfs.cpio"
+CONFIG_INITRAMFS_SOURCE="new_initramfs.cpio"
 # CONFIG_RD_BZIP2 is not set
 # CONFIG_RD_LZMA is not set
 # CONFIG_RD_XZ is not set

Build openSBI with linux kernel payload

make linux

Run linux on emulator

make linux-qemu
make linux-spike
make linux-csim # WARNING: takes a long time

Xvisor

Create device files (can't be tracked by git)

sudo mknod -m 666 initramfs/dev/null c 1 3

sudo mknod -m 600 initramfs/dev/console c 5 1

Build openSBI with xvisor payload & initrd containing a Linux image

make xvisor

Update location of xvisor's initrd

Find initrd address & update rv64gch_xvisor.dts

riscv64-unknown-linux-gnu-objdump -x target/opensbi_xvisor_payload.elf | grep _initrd_

   chosen {
     stdout-path = &HTIF;
     bootargs = "vmm.bootcmd=\"vfs mount initrd /; vfs run /boot.xscript\"";
-    linux,initrd-start = <0x82000000>;
+    linux,initrd-start = <0x802a9540>;
-    linux,initrd-end   = <0x82800000>;
+    linux,initrd-end   = <0x812eef40>;
   };

Run xvisor on emulator

echo "autoexec" | make xvisor-spike
echo "autoexec" | make xvisor-csim # WARNING: takes a very long time