---
tags: Linux Kernel
---
# Linux on Virtual Machine (QEMU)
contributed by < Dung-Ru Tsai >
# Ubuntu Image on [QEMU](https://www.qemu.org/download/)
**1. Build and Install QEMU**
```bash
git clone https://gitlab.com/qemu-project/qemu.git
cd qemu
git submodule init
git submodule update --recursive
git checkout v6.1.0
mkdir build
cd build
../configure --prefix=/usr/local/bin \
--enable-debug \
--enable-virtfs
make -j8
sudo make install
```
:::success
[Dependency](https://wiki.qemu.org/Hosts/Linux#Simple_build_and_test):
```
sudo apt-get install git libglib2.0-dev libfdt-dev libpixman-1-dev zlib1g-dev
```
:::
**2. Bridge host network with TAP interface**
> [Setting up Qemu with a tap interface](https://gist.github.com/extremecoders-re/e8fd8a67a515fee0c873dcafc81d811c)
- Create a bridge interface on Host (by netplan)
```bash
vim /etc/netplan/01-network-manager-all.yaml
===== copy start =====
network:
version: 2
renderer: networkd
ethernets:
eno1:
dhcp4: false
dhcp6: false
bridges:
br0:
interfaces: [eno1]
addresses: [192.168.100.4/24]
gateway4: 192.168.100.254
mtu: 1500
nameservers:
addresses: [8.8.8.8]
parameters:
stp: false
forward-delay: 4
dhcp4: false
dhcp6: true
===== copy end =====
sudo netplan apply
```
- Create tap0 interface
[bridge network with tap](https://blog.elastocloud.org/2015/07/qemukvm-bridged-network-with-tap.html)
```bash=
sudo ip tuntap add dev tap0 mode tap
sudo ip link set dev tap0 master br0
sudo ip link set dev tap0 up
```
**3. Create Disk image**
```shell
qemu-img create -f qcow2 kvm-generic.qcow2 30G
```
**4. Install Ubuntu ISO**
> [qemu ubuntu20.04](https://www.arthurkoziel.com/qemu-ubuntu-20-04/)
> [qemu quick reference](https://www.notion.so/QEMU-11408fae00c74630914c044f815d8549)
```bash=
#!/bin/bash
PREFIX=/home/jake/mount_1TB/gns3server
ISO=${PREFIX}/ubuntu-20.04.3-live-server-amd64.iso # Installation media
NET=br0 # bridge name
OS=linux # os type
VM_DISK=${PREFIX}/kvm-generic.qcow2 # VM image on disk
sudo qemu-system-x86_64 \
-machine type=q35,accel=hvf \
-smp 2 \
-hda ${VM_DISK}\
-cdrom ${ISO} \
-m 4096 \
-vga virtio \
-usb \
-device usb-tablet \
-enable-kvm \
-cpu host \
-display default \
-boot d \
-netdev tap,id=mynet0,ifname=tap0,script=no,downscript=no \
-device e1000,netdev=mynet0,mac=52:55:00:d1:55:01
```
:::success
QEMU Parameter help
`qemu-system-x86_64 -accel ?`
`qemu-system-x86_64 -netdev ?`
:::
- Connect to VNC: `127.0.0.1:5900`
**5. Running the system**
```bash
#!/bin/bash
PREFIX=/home/jake/mount_1TB/gns3server
NET=br0 # bridge name
OS=linux # os type
VM_DISK=${PREFIX}/kvm-generic.qcow2 # VM image on disk
sudo ip tuntap add dev tap0 mode tap
sudo ip link set dev tap0 master br0
sudo ip link set dev tap0 up
sudo qemu-system-x86_64 \
-machine type=q35,accel=hvf \
-smp 4 \
-hda ${VM_DISK}\
-m 4096 \
-vga virtio \
-usb \
-device usb-tablet \
-enable-kvm \
-cpu host \
-netdev tap,id=mynet0,ifname=tap0,script=no,downscript=no \
-device e1000,netdev=mynet0,mac=52:55:00:d1:55:01 \
-serial telnet:127.0.0.1:4322,server,nowait \
-display default
-nographic
```
[Another example](https://gist.github.com/dungru/bf11265caf466d5a82672f3e984c8be9)
**6. Redirect GRUB output to serial console (optional)**
> [SerialConsoleHowto](https://help.ubuntu.com/community/SerialConsoleHowto)
- Connect to VNC
- Edit the `/etc/default/grub`, redirect serial message to ttyS0
```bash=
# If you change this file, run 'update-grub' afterwards to update
# /boot/grub/grub.cfg.
GRUB_DEFAULT=0
GRUB_TIMEOUT=1
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX="console=tty0 console=ttyS0,115200n8"
# Uncomment to disable graphical terminal (grub-pc only)
GRUB_TERMINAL=serial
GRUB_SERIAL_COMMAND="serial --speed=115200 --unit=0 --word=8 --parity=no --stop=1"
...
```
- Update the GRUB
```bash
sudo update-grub
reboot
# Open another terminal
telnet 127.0.0.1 4322
```
**7. Connect with ssh**
```
ssh dutsai@your-vm-ip
```
- [Install/running scripts](https://gist.github.com/dungru/96f4dd9f7a69c6baae1c77425f5a25af)
# Enlarge the disk on VM
https://www.linuxtechi.com/extend-lvm-partitions/
https://www.tecmint.com/extend-and-reduce-lvms-in-linux/
- Add new the partition
```shell=
qemu-img resize kvm-generic.qcow2 +60G
sudo fdisk -l
sudo fdisk -cu /dev/sda
To Create new partition Press n.
Change the type using t.
Type 8e to change the partition type to Linux LVM.
Press w to write the changes.
sudo sudo fdisk -l #check
```
- Add new physical volume and add to volume group
```shell=
# Add physical volume
sudo pvcreate /dev/sda4
$ sudo pvs
PV VG Fmt Attr PSize PFree
/dev/sda3 ubuntu-vg lvm2 a-- <29.00g 0
/dev/sda4 ubuntu-vg lvm2 a-- 29.26g 0
# Extend Volume Group
sudo vgextend ubuntu-vg /dev/sda4
$ sudo vgs # check volume
VG #PV #LV #SN Attr VSize VFree
ubuntu-vg 1 1 0 wz--n- <29.00g <9.00g
```
- Resize Logical Volume
```shell=
# Get LV Path
sudo lvdisplay
# Do it
$ sudo lvextend /dev/ubuntu-vg/ubuntu-lv -l+100%FREE
$ sudo resize2fs -p /dev/ubuntu-vg/ubuntu-lv
$ df -h /
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/ubuntu--vg-ubuntu--lv 28G 19G 8.1G 70% /
```
-------
< obsoleted >
# ARM64 QEMU Environment Setting
## Method01: buildroot
### 1. Set up the QEMU for aarch64
```shell=
wget https://download.qemu.org/qemu-2.12.1.tar.xz
tar xvJf qemu-2.12.1.tar.xz
cd qemu-2.12.1
./configure --target-list=aarch64-softmmu
# Work with VirtIO + 9P
sudo apt-get install libcap-dev libattr1-dev
./configure --enable-virtfs --target-list=aarch64-softmmu
make
```
`--enable-virtfs` : 使得 VirtIO + 9P 可以運作，
`--target-list` : 只產生可以運行 aarch64 架構的 qemu
耐心等待一段時間之後，在 `aarch64-softmmu` 目錄下可以找到
`qemu-system-aarch64`
- Install the binary qemu-system-aarch64 to /usr/bin/
```shell
#$ sudo cp qemu-2.12.1/aarch64-softmmu/qemu-system-aarch64 /usr/bin
sudo make install
```
:::info
Buildroot Guide
- 第3章 行程(process)環境:https://hackmd.io/s/rJf1ONuye
- from link: [Taiwan linux study group](https://hackmd.io/KYRgLADAZgJgzFAtAQwBxwKyLHYrEBGAbBmIsBARGAQJxgDGUlQA)
:::
### 2. Build AArch64 image with buildroot
```shell=
$ sudo apt-get install libncurses-dev
$ git clone https://github.com/buildroot/buildroot
$ make list-defconfigs
# Generate the .config
$ make qemu_aarch64_virt_defconfig
$ make menuconfig
# 使用Kernel 5.0 header
$ make linux-menuconfig
# 開啟 9P File System
$ make
```
- [設定Kernel 5.0 教學](https://hackmd.io/s/ryQIj1MKV#%E8%AA%BF%E6%95%B4%E8%87%B3-Linux-50x)
- 9P File System9P File System [設定教學](https://wiki.qemu.org/Documentation/9psetup)
### 3. Run the emulation Qemu
```shell=
$ qemu-system-aarch64 -M virt \
-cpu cortex-a53 \
-nographic -smp 1 \
-kernel output/images/Image \
-append "root=/dev/vda console=ttyAMA0" \
-netdev user,id=eth0 -device virtio-net-device,netdev=eth0 \
-drive file=output/images/rootfs.ext4,if=none,format=raw,id=hd0 \
-device virtio-blk-device,drive=hd0 \
-fsdev local,security_model=passthrough,id=fsdev0,path=/tmp \
-device virtio-9p-pci,id=fs0,fsdev=fsdev0,mount_tag=host_mount
```
注意最後兩行 `-fsdev` and `-device`, 是為了掛載 host 的目錄才有的
### 4. 掛載 host 的目錄
```shell=
mkdir share
mount -t 9p -o trans=virtio host_mount share -oversion=9p2000.L
```
Reference:
[0xff07](https://hackmd.io/s/ryQIj1MKV#2019q1-Homework4-smallsys)
[9psetup](https://wiki.qemu.org/Documentation/9psetup)
## Method-02: Kernel source
### 1. Set up the QEMU for aarch64
```shell=
wget https://download.qemu.org/qemu-2.12.1.tar.xz
tar xvJf qemu-2.12.1.tar.xz
cd qemu-2.12.1
./configure --target-list=aarch64-softmmu
# Work with VirtIO + 9P
sudo apt-get install libcap-dev libattr1-dev
./configure --enable-virtfs --target-list=aarch64-softmmu
make
```
`--enable-virtfs` : 使得 VirtIO + 9P 可以運作，
`--target-list` : 只產生可以運行 aarch64 架構的 qemu
耐心等待一段時間之後，在 `aarch64-softmmu` 目錄下可以找到
`qemu-system-aarch64`
- Install the binary qemu-system-aarch64 to /usr/bin/
```shell
$ sudo cp qemu-2.12.1/aarch64-softmmu/qemu-system-aarch64 /usr/bin
sudo make install
```
### 2. Create initramfs cpio (Create the file system)
```shell
$ git clone https://github.com/buildroot/buildroot
$ make list-defconfigs
$ make qemu_aarch64_virt_defconfig
$ make menuconfig
```
- Target options —> Target Architecture: 選擇 AArch64 little-endian
- Toolcahin —> Toolchain type: 選擇 External toolchain
Toolchain: 選擇 Linaro AArch64 2018.05
- System configuration —> Run a getty (login prompt) after boot
TTY port 改為 ttyAMA0
- Filesystem images —> cpio the root filesystem (for use as an initial RAM filesystem)
儲存之後，進行 make。若無異常，可以在 output/images 目錄底下找到 **rootfs.cpio**
### 3. Build aarch64 Kernel from source
:::info
Kernel Source code
- [Linux Kernel]( https://www.kernel.org/pub/linux/kernel/ )
- [Preempty Kernel patch]( https://www.kernel.org/pub/linux/kernel/projects/rt/)
- [Building the preeempty kernel on ubuntu](https://ubuntuforums.org/showthread.php?t=2273355)
:::
```shell=
git clone https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git linux-stable
cd linux-stable
sudo apt-get install gcc-aarch64-linux-gnu
make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- defconfig
make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- menuconfig
```
Edit the .config for 9P
```shell=
CONFIG_CMDLINE="console-ttyAMA0"
# points at your buildrootimage
CONFIG_INITRAMFS_SOURCE="/home/jake/QEMU/rootfs.cpio"
# needed for virtfs mount
CONFIG_NET_9P=y
CONFIG_NET_9P_VIRTIO=y
```
一切就緒就開始編譯核心
```shell=
## Build the Kernel
make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu-
```
The image path will show at `arch/arm64/boot/Image` or linux/vmlinux
### 4. Run the emulation QEMU
```shell=
#!/bin/bash
qemu-system-aarch64 \
-machine virt \
-machine type=virt \
-cpu cortex-a57 \
-nographic -smp 1 \
-m 8192 \
-kernel /home/jake/QEMU/linux-stable/arch/arm64/boot/Image \
--append "console=ttyAMA0" \
-fsdev local,security_model=passthrough,id=test_dev,path=/home/jake/Workspace/ -device virtio-9p-pci,id=fsdev0,fsdev=test_dev,mount_tag=host_mount
```
- `-kernel` : 指定第二步驟編譯好的 image path
- `-fsdev, path` : 指定共享目錄的路徑
- path 是在 host 這邊要目錄分享的路徑，這邊是用 `/home/jake/Workspace/`
- 而最後面那個 `mount_tag=host_mount` 是到時候在 guest 裡面 mount 時會用到.
### 5. 掛載 host 的目錄
透過 VirtIO + 9P 使得 guest 與 host 共享目錄:
`mount -t 9p -o trans=virtio host_mount /mnt`
- Exit the QEMU:
Ctrl+a X
#### Reference
- Video: [Starting Linux kernel exploration with Eukabuka](https://www.youtube.com/watch?v=zK2Agg3U2cU)
- QEMU Source :https://www.qemu.org/download/#source
- [Running Linux in QEMU’s aarch64 system emulation mode](https://www.bennee.com/~alex/blog/2014/05/09/running-linux-in-qemus-aarch64-system-emulation-mode/)
- [atlantis0914](https://hackmd.io/s/HJb80Rdt4#2019q1-Homework4-smallsys)
# X86_64 QEMU Environment Setting
[PASS]
## Method-01 buildroot source
### 1. Build the QEMU
```shell
wget https://download.qemu.org/qemu-4.2.0.tar.xz
tar xvJf qemu-4.2.0.tar.xz
cd qemu-4.2.0
# Work with VirtIO + 9P
sudo apt-get install libcap-dev libattr1-dev
sudo apt install build-essential kernel-package fakeroot libncurses5-dev libssl-dev ccache flex bison libelf-dev
sudo apt-get install libglib2.0-dev libfdt-dev libpixman-1-dev zlib1g-dev install libnfs-dev libiscsi-dev
./configure --enable-virtfs --target-list=x86_64-softmmu --enable-debug
make -j8
... wait for a while
sudo make install
```
`--enable-virtfs`: Enable the virtual file IO system
### 2. Build the Linux from buildroot
Check the basic build guide in`cat README`
```shell
make list-defconfigs
make qemu_x86_64_defconfig
make
# find the kernel, bootloader, root filesystem, etc. in output/images
```
### 3. Run the qemu with Linux
Check the qemu startup guide
`cat board/qemu/x86_64/readme.txt`
```shell
qemu-system-x86_64 -M pc \
-kernel output/images/bzImage \
-drive file=output/images/rootfs.ext2,if=virtio,format=raw \
-append "rootwait root=/dev/vda console=tty1 console=ttyS0" \
-serial stdio \
-net nic,model=virtio \
-net user
# Optionally add -smp N to emulate a SMP system with N CPUs.
```
:::success
```shell
udhcpc: sending select for 10.0.2.15
udhcpc: lease of 10.0.2.15 obtained, lease time 86400
deleting routers
random: mktemp: uninitialized urandom read (6 bytes read)
adding dns 10.0.2.3
OK
Welcome to Buildroot
buildroot login: root
```
:::
## Method-02 Kernel Source
### 1. Build the QEMU
```shell
sudo apt update -y
sudo apt install libcap-ng-dev libattr1-dev build-essential kernel-package fakeroot libncurses5-dev libssl-dev ccache flex bison libelf-dev libglib2.0-dev libfdt-dev libpixman-1-dev zlib1g-dev libnfs-dev libiscsi-dev ninja-build
wget https://download.qemu.org/qemu-6.2.0.tar.xz
tar xvJf qemu-6.2.0.tar.xz
cd qemu-6.2.0
./configure --enable-virtfs --target-list=x86_64-softmmu --enable-debug
make -j8
... wait for a while
sudo make install
```
`--enable-virtfs`: Enable the virtual file IO system
### 2.1 Create the root file system
```shell
$ git clone https://github.com/buildroot/buildroot
$ make list-defconfigs
$ make qemu_x86_64_defconfig
$ make menuconfig
```
- Target options —> Target Architecture: 選擇 x86_64
- Filesystem images —> ext2/3/4 root file system
:::info
cpio the root filesystem (for use as an initial RAM filesystem)
:::
儲存之後，進行 make。若無異常，可以在 output/images 目錄底下找到 **rootfs.cpio**
### 2.2 Build Kernel from linux source
- [Prepare the environment for developing Linux kernel with qemu](https://medium.com/@daeseok.youn/prepare-the-environment-for-developing-linux-kernel-with-qemu-c55e37ba8ade)
- https://mirrors.edge.kernel.org/pub/linux/kernel/
```bash=
make ARCH=x86_64 x86_64_defconfig
make ARCH=x86_64 menuconfig
make -j8
```
- Kernel hacking -> Compile the kernel with debug info -> Provide GDB scripts for kernel debugging
- `Reduce debugging information` option off
- Force unload the kernel module: `MODULE_FORCE_UNLOAD`
- KGDB
```shell
CONFIG_DEBUG_INFO=y
CONFIG_FRAME_POINTER=y
CONFIG_HAVE_ARCH_KGDB=y
CONFIG_KGDB=y
CONFIG_KGDB_SERIAL_CONSOLE=y
```
- Ensure the following 9P options are enabled in the kernel configuration.
```shell
CONFIG_NET_9P=y
CONFIG_NET_9P_VIRTIO=y
CONFIG_NET_9P_DEBUG=y (Optional)
CONFIG_9P_FS=y
CONFIG_9P_FS_POSIX_ACL=y
CONFIG_PCI=y
CONFIG_VIRTIO_PCI=y
CONFIG_PCI_HOST_GENERIC=y (only needed for the QEMU Arm 'virt' board)
```
The final image will show in `arch/x86/boot/bzImage`.
- ramfile system only
```
# Only for ramfile system when you choose in builtroot Filesystem images is cpio:
CONFIG_INITRAMFS_SOURCE="/home/jake/QEMU/rootfs.cpio"
```
### 3.1 Run qemu with own Linux Kernel (No File system)
```shell
qemu-system-x86_64 -s -S\
-kernel arch/x86/boot/bzImage \
-hda /dev/zero \
-append "root=/dev/zero console=ttyS0" \
-serial stdio -display none
```
Try the KGDB
```shell
cd linux
gdb ./vmlinux
(gdb) target remote localhost:1234
(gdb) break start_kernel
(gdb) c
Continuing.
Breakpoint 1, start_kernel () at init/main.c:786
786 {
```
### 3.2 Run qemu with own Linux Kernel with Files system
```bash
qemu-system-x86_64 -kernel arch/x86/boot/bzImage \
-boot c -m 2049M \
-append "root=/dev/sda rw console=ttyS0,115200 acpi=off nokaslr" \
-hda output/images/rootfs.ext4 \
-fsdev local,security_model=passthrough,id=fsdev0,path=/home/dutsai/Workspace_vm \
-device virtio-9p-pci,id=fs0,fsdev=fsdev0,mount_tag=host_mount \
-nographic \
-monitor telnet::45454,server,nowait \
-serial mon:stdio
```
- `-kernel` : 指定第二步驟編譯好的 image path
- `-fsdev, path` : 指定共享目錄的路徑
- path 是在 host 這邊要目錄分享的路徑，這邊用 `/home/dutsai/Workspace_vm`
- `mount_tag=host_mount` 在 guest 裡面 mount 時會用.
- `-serial mon:stdio` Send Ctrl+C to guest
- `Ctrl+a X` to exit qemu.
### 4. Mount host folder
https://wiki.qemu.org/Documentation/9psetup
```bash=
# In qemu
mount -t 9p -o trans=virtio host_mount /root -oversion=9p2000.L
```
### 5. KGDB
```shell
qemu-system-x86_64 \
-kernel linux-5.16.14/arch/x86/boot/bzImage \
-boot c -m 4096M \
-append "root=/dev/sda rw console=ttyS0,115200 acpi=off nokaslr" \
-hda buildroot/output/images/rootfs.ext4 \
-fsdev local,security_model=passthrough,id=fsdev0,path=/home/dutsai/Workspace_vm \
-device virtio-9p-pci,id=fs0,fsdev=fsdev0,mount_tag=host_mount \
-nographic \
-monitor telnet::45454,server,nowait \
-serial mon:stdio \
-S -gdb tcp::33004
```
Try to open another terminal to run gdb.
```shell
cd linux
gdb ./vmlinux
(gdb) target remote localhost:33004
(gdb) break start_kernel
(gdb) c
Continuing.
Breakpoint 1, start_kernel () at init/main.c:786
786 {
```
## Method-03 Ycoto
[RISC-V Embedded Linux - Get started with Buildroot/Yocto](https://hackmd.io/@coscup/SJLHICJTc/%2F%40coscup%2FSkfNICy69)
# Update Linux Kernel
:::info
Kernel Source code
- [Linux Kernel]( https://www.kernel.org/pub/linux/kernel/ )
- [Preempty Kernel patch]( https://www.kernel.org/pub/linux/kernel/projects/rt/)
- [Building the preeempty kernel on ubuntu](https://ubuntuforums.org/showthread.php?t=2273355)
:::
- Get from Newest [release](https://github.com/torvalds/linux/tags)
- [Ubuntu 22.04 is Jammy Jellyfish](https://code.launchpad.net/~ubuntu-kernel/ubuntu/+source/linux/+git/jammy)
- [將 memchr() 放入核心並重新 compile](https://hackmd.io/@arthur-chang/linux2022-quiz8?fbclid=IwAR3TsBYPmvISIC7xcYQ8s2uPZo9aWk7vm8DZqHwMdggfH5PVUKcUgnAJfCs#%E5%B0%87-memchr-%E6%94%BE%E5%85%A5%E6%A0%B8%E5%BF%83%E4%B8%A6%E9%87%8D%E6%96%B0-compile)
Source code: https://www.kernel.org/
```shell=
$ sudo apt-get install liblz4-tool libc6-dev libncurses5-dev openssl wget ca-certificates bc libzstd-dev zstd
$ sudo apt-get install git fakeroot build-essential ncurses-dev xz-utils libssl-dev bc flex libelf-dev bison dwarves
$ wget https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.17.9.tar.xz
$ cp /boot/config-`uname -r` .config
$ make menuconfig
選擇 load 再選擇 save
# make ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- menuconfig
$ scripts/config --disable SYSTEM_TRUSTED_KEYS
$ scripts/config --disable SYSTEM_REVOCATION_KEYS
CONFIG_DEBUG_INFO_BTF=n
# Build
$ make -j12
$ make modules -j12
# Install
$ sudo make INSTALL_MOD_STRIP=1 modules_install -j 4
$ sudo make install
$ sudo mkinitramfs /lib/modules/5.17.9/ -o /boot/initrd.img-5.17.9
$ sudo update-grub2
# Install Method2
$ su -c "make modules_install install"
```
### Update the GRUB
vim /etc/default/grub
```
GRUB_DEFAULT="Advanced options for Ubuntu>Ubuntu, with Linux 5.10.130-0510130-generic"
# GRUB_TIMEOUT_STYLE=hidden
GRUB_TIMEOUT=8
$ sudo update-grub
```
# Patch RT (Linux)
- Install the ubuntu 16.04
- [Building and Install the preeempt kernel on Ubuntu](https://ubuntuforums.org/showthread.php?t=2273355)
- Kernel Version https://www.kernel.org/pub/linux/kernel/
- linux-4.4.60
- Preempt RT Version https://www.kernel.org/pub/linux/kernel/projects/rt/
- patch-4.4.60-rt73 (Linux preempt RT 4.4.60-rt73+)
- https://mirrors.edge.kernel.org/pub/linux/kernel/projects/rt/4.4/older/patch-4.4.60-rt73.patch.gz
- [Linux RT Kernel config](https://gist.github.com/ldotrg/c69d0ee45ab28884d26c9ba8fc275e70) replace the `.config` file
- Must turn off **Check for stack overflows**
- `sudo apt-get install libssl-dev`
### build kernel command
```shell=
$ sudo apt-get update
$ sudo apt-get install build-essential linux-tools-common linux-tools-generic cmake automake libtool libusb-1.0-0-dev openssh-server samba vim linux-headers-`uname -r` can-utils libpopt-dev
$ mkdir -p kernel
$cd kernel
# Download the kernel linux-4.4.60.tar.gz and patch-4.4.60-rt73.patch.gz
$ wget https://mirrors.edge.kernel.org/pub/linux/kernel/v4.x/linux-4.4.60.tar.gz
$ wget https://mirrors.edge.kernel.org/pub/linux/kernel/projects/rt/4.4/older/patch-4.4.60-rt73.patch.gz
$ tar -xzvf linux-4.4.60.tar.gz
$ cd linux-4.4.60
$ gzip -cd ../patch-4.4.60-rt73.patch.gz | patch -p1 --verbose
$ sudo apt-get install libncurses-dev libssl-dev
# Change .config file
$ make menuconfig
##Graphical Menu##
# Processor type and features ---> [Enter]
# Preemption Model (Voluntary Kernel Preemption (Desktop)) [Enter]
# Fully Preemptible Kernel (RT) [Enter] #Select
# [Esc][Esc]
# <Save> [Enter]
/*
# Kernel hacking --> [Enter]
# Memory Debugging [Enter]
# Check for stack overflows #Already deselected - do not select
# [Esc][Esc]
# [Right Arrow][Right Arrow]
# .config
# <Okay> [Enter]
# <Exit> [Enter]
# [Esc][Esc]
# [Right Arrow]
# <Exit> [Enter]
*/
make
sudo make modules_install -j3
sudo make install -j3
```
:::danger
- [Linux RT Kernel .config simple](https://gist.github.com/ldotrg/c69d0ee45ab28884d26c9ba8fc275e70) replace the `.config` file in Linux-4.4.60
- [EGSE .config full](https://gist.github.com/ldotrg/1ca2213f8c8569f59f4169a5ac4eab71)
:::
**After install the kernel**
- Verify and update. Verify that
`initrd.img-4.4.60-rt73`,
`vmlinuz-4.4.60-rt73`, and
`config-4.4.60-rt73` exist. They should have been created in the previous step.
```shell
$cd /boot
$ ls
```
### Set the default kernel
**1. Go to see the menuentry in**
```shell
vim /boot/grub/grub.cfg
```
search your menuentry version and copy it.
```
menuentry 'Ubuntu, with Linux 4.4.60-rt73'
```
2. **sudo vim /etc/default/grub**
```shell=
$ sudo vim /etc/default/grub
GRUB_DEFAULT='Advanced options for Ubuntu>Ubuntu, with Linux 4.4.60-rt73'
GRUB_CMDLINE_LINUX_DEFAULT="isolcpus=1"
```
:::danger
CPU Isolation
```shell=
sudo vim /etc/default/grub ===> add GRUB_CMDLINE_LINUX_DEFAULT="isolcpus=1"
sudo update-grub
sudo reboot
# Loogin Permission
sudo vim /etc/ssh/sshd_config ===> modify "PermitRootLogin yes"
```
:::
3. **sudo update-grub**
- it will show the error message, please change the GRUB_DEFAULT by use the correct one on error message.
4. In BIOS, Turn off Hyper threading
# Lima macOS
1st Start
```
limactl start --name=default template://ubuntu-lts
limactl shell default
```
https://github.com/lima-vm/lima
```
sudo apt-get install sshfs build-essential linux-tools-common linux-tools-generic automake* linux-headers-`uname -r` net-tools wireless-tools
```
[linux-image-5.4.0-109-generic_5.4.0-109.123_arm64.deb](https://ubuntu.pkgs.org/20.04/ubuntu-proposed-main-arm64/linux-image-5.4.0-109-generic_5.4.0-109.123_arm64.deb.html)
```
sudo apt install linux-modules-extra-`uname -r`
```
- YAML file on mac:
```
vim /Users/dutsai/.lima/default
# Ubuntu 20.04 LTS (Focal Fossa)
# This example requires Lima v0.7.0 or later.
images:
# Try to use release-yyyyMMdd image if available. Note that release-yyyyMMdd will be removed after several months.
- location: "https://cloud-images.ubuntu.com/releases/20.04/release-20220302/ubuntu-20.04-server-cloudimg-amd64.img"
arch: "x86_64"
digest: "sha256:243157ea0390890d6e60ce5e08e0249b16e23b6b313b63aed50f39f92b020afe"
- location: "https://cloud-images.ubuntu.com/releases/20.04/release-20220302/ubuntu-20.04-server-cloudimg-arm64.img"
arch: "aarch64"
digest: "sha256:fb2b4efdbf0011bd2a9fd49e9d31efdd252966c889f07b5d246351ec5734a329"
# Fallback to the latest release image.
# Hint: run `limactl prune` to invalidate the cache
- location: "https://cloud-images.ubuntu.com/releases/20.04/release/ubuntu-20.04-server-cloudimg-amd64.img"
arch: "x86_64"
- location: "https://cloud-images.ubuntu.com/releases/20.04/release/ubuntu-20.04-server-cloudimg-arm64.img"
arch: "aarch64"
mounts:
- location: "~"
- location: "~/Workspace_mac/vwifi"
writable: true
- location: "/tmp/lima"
writable: true
```
# User mode Linux
https://hackmd.io/@sysprog/user-mode-linux-env
```shell
$ sudo apt install build-essential libncurses-dev flex bison
$ sudo apt install xz-utils wget ca-certificates bc fakeroot
$ wget https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.12.tar.xz
$ tar xvf linux-5.12.tar.xz
$ make mrproper
$ make defconfig ARCH=um SUBARCH=x86_64
$ make linux ARCH=um SUBARCH=x86_64 -j `nproc`
```
- Root file system
```shell
$ export REPO=http://dl-cdn.alpinelinux.org/alpine/v3.13/main
$ mkdir -p rootfs
$ curl $REPO/x86_64/APKINDEX.tar.gz | tar -xz -C /tmp/
$ export APK_TOOL=`grep -A1 apk-tools-static /tmp/APKINDEX | cut -c3- | xargs printf "%s-%s.apk"`
$ curl $REPO/x86_64/$APK_TOOL | fakeroot tar -xz -C rootfs
$ fakeroot rootfs/sbin/apk.static \
--repository $REPO --update-cache \
--allow-untrusted \
--root $PWD/rootfs --initdb add alpine-base
$ echo $REPO > rootfs/etc/apk/repositories
$ echo "LABEL=ALPINE_ROOT / auto defaults 1 1" >> rootfs/etc/fstab
```
- UML.sh
```
```
[howto-usermode-linux](
https://xeiaso.net/blog/howto-usermode-linux-2019-07-07)
### Original Assignment info: [F08: smallsys](https://hackmd.io/s/BkhVVlHu4#F08-smallsys)
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