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				################################################################################
				LLDB Testing on AArch64 SVE Linux using QEMU system mode emulation
				################################################################################

				QEMU can be used to test LLDB in an emulation environment in the absence of
				actual hardware. This write up will help setup a QEMU environment for testing
				rovkaUnsubmitted Not Done Reply Inline Actions Nitpick: "in an emulation environment in the absence of actual [...] rovka: Nitpick: "in an emulation environment in the absence of actual [...]
				AArch64 features like SVE, MTE, Pointer Authentication etc. This write can be
				used as reference to setup similar testing environment for other architectures
				rovkaUnsubmitted Not Done Reply Inline Actions Isn't this guide still useful after the patches are merged? rovka: Isn't this guide still useful after the patches are merged?
				supported by QEMU emulator.

				rovkaUnsubmitted Not Done Reply Inline Actions Typo: all the instructions rovka: Typo: all the instructions
				Ubuntu Bionic/Focal x86_64 host was used to test all the instructions in this
				document. Please update it according to your host distribution/architecture.
				################################################################################
				# STEP 1
				################################################################################
				# Bash script for creating Debian/Ubuntu Linux RootFS for QEMU system emulation
				# Example usage:
				# To create an img file of size 8 GB containing Ubuntu Bionic arm64 rootFS
				# > bash create-qemu-rootfs.sh bionic-arm64 8G bionic arm64
				################################################################################
				rovkaUnsubmitted Not Done Reply Inline Actions Would it be better for this to be an actual script in lldb/utils or somewhere similar? rovka: Would it be better for this to be an actual script in lldb/utils or somewhere similar?
				#!/bin/bash

				# Prerequisites:
				sudo apt-get install debootstrap qemu-user-static schroot qemu-utils

				if [ $# -gt 3 ]; then
				echo "Your command line contains $# arguments"
				else
				echo "Invalid or no arguments"
				echo "Usage example: create-rootfs-qemu.sh focal-arm64 8G focal arm64"
				echo "focal-arm64 is image name"
				echo "8G is image size in Gigabytes"
				echo "focal is distro name"
				echo "arm64 is rootFS architecture"
				exit
				fi

				RFS_IMG_NAME=$1
				shift
				RFS_IMG_SIZE_GB=$1
				labathUnsubmitted Not Done Reply Inline Actions Why not just `RFS_IMG_SIZE_GB=$2`, etc., without all the shifts? labath: Why not just `RFS_IMG_SIZE_GB=$2`, etc., without all the shifts?
				shift
				BOOTSTRAP_DISTRO=$1
				shift
				BOOTSTRAP_ARCH=$1

				echo "Root FS image name ... $RFS_IMG_NAME"
				echo "Root FS size in GB ... $RFS_IMG_SIZE_GB"
				echo "Root FS bootstrap distro name ... $BOOTSTRAP_DISTRO"
				echo "Root FS bootstrap distro architecture... $BOOTSTRAP_ARCH"

				qemu-img create $RFS_IMG_NAME.img $RFS_IMG_SIZE_GB

				mkfs.ext4 $RFS_IMG_NAME.img
				mkdir $RFS_IMG_NAME.dir
				sudo mount -o loop $RFS_IMG_NAME.img $RFS_IMG_NAME.dir

				sudo qemu-debootstrap --arch $BOOTSTRAP_ARCH $BOOTSTRAP_DISTRO $RFS_IMG_NAME.dir

				sudo chroot $RFS_IMG_NAME.dir locale-gen en_US.UTF-8

				sudo chroot $RFS_IMG_NAME.dir sed -i \
				's/main/main restricted multiverse universe/g' /etc/apt/sources.list

				sudo chroot $RFS_IMG_NAME.dir sed -i '$ a\nameserver 8.8.8.8' /etc/resolv.conf

				sudo chroot $RFS_IMG_NAME.dir apt update
				sudo chroot $RFS_IMG_NAME.dir apt -y install ssh bash-completion
				sudo chroot $RFS_IMG_NAME.dir adduser --gecos "" $USER
				sudo chroot $RFS_IMG_NAME.dir adduser $USER sudo
				sudo umount $RFS_IMG_NAME.dir
				rmdir $RFS_IMG_NAME.dir

				################################################################################
				# End of STEP 1
				################################################################################

				################################################################################
				# STEP 2
				#
				rovkaUnsubmitted Not Done Reply Inline Actions Is this difficult to infer from QEMU's own docs? If not, maybe just add a link and mention only what's specific to this guide (I'm guessing the target-list). rovka: Is this difficult to infer from QEMU's own docs? If not, maybe just add a link and mention only…
				# Build QEMU from source for AArch64 system-mode emulation
				#
				# Please visit https://wiki.qemu.org/Hosts/Linux for instructions
				# on how to build QEMU from source.
				#
				# In order to enable AArch64 system by QEMU please run configure QEMU resources
				# with following arguments: ./configure --target-list=aarch64-softmmu
				#
				# Please run ./configure --help inside QEMU source directory for a complete
				# list of supported emulation targets.
				################################################################################

				# Install dependencies
				sudo apt-get build-dep qemu
				sudo apt install libsdl2-dev

				# Checkout source code
				git clone git://git.qemu.org/qemu.git qemu.git
				rovkaUnsubmitted Not Done Reply Inline Actions Same as above, could this be just a link to the official docs? rovka: Same as above, could this be just a link to the official docs?

				# Configure and build
				cd qemu.git
				./configure --target-list=aarch64-softmmu
				make

				################################################################################
				# STEP 3
				#
				# Cross compile Linux kernel
				################################################################################

				# Install dependencies
				sudo apt install gcc-arm-linux-gnueabihf gcc-aarch64-linux-gnu

				# Checkout source code, select branch and clean up source directory
				git clone \
				https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git linux.git

				cd linux.git
				make mrproper

				# kernel_branch=master arch=arm64 config=defconfig
				make O=../linux.build/master/arm64 ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu- \
				defconfig

				make O=../linux.build/master/arm64 ARCH=arm64 CROSS_COMPILE=aarch64-linux-gnu-

				rovkaUnsubmitted Not Done Reply Inline Actions Same as step 1: can this live in utils? rovka: Same as step 1: can this live in utils?

				################################################################################
				# STEP 4
				#
				# AArch64 SVE System Mode Emulation
				#
				# Bash script given below boots our newly built AArch64 Linux kernel using
				# RootFS img file created in step 1.
				################################################################################
				#!/bin/bash

				if [ $# -gt 2 ]; then
				echo "Your command line contains $# arguments"
				else
				echo "Invalid or no arguments"
				echo "Usage example: sudo bash run-qemu-emulation.sh \
				./qemu.git/aarch64-softmmu/qemu-system-aarch64 \
				./linux.build/master/arm64/ ./bionic-arm64.img"
				echo "First argument is .. qemu-system-aarch64"
				echo "Second argument is .. Linux kernel build directory"
				echo "Third argument is .. RootFS image file"
				exit
				fi

				QEMU_AARCH64=$1
				shift
				LINUX_BUILD=$1
				shift
				QEMU_RFS_IMG=$1

				echo "QEMU AArch64 system emulation executable ... $QEMU_AARCH64"
				echo "Root FS image name ... $QEMU_RFS_IMG"
				echo "Linux ARM64 build directory ... $LINUX_BUILD"

				LINUX_DTBS=$LINUX_BUILD/arch/arm64/boot/dts/

				QEMU_MACHINE=virt
				QEMU_CPU=max
				QEMU_CORES=2
				QEMU_MEMORY=2048
				QEMU_GDBSERVER_HOST_PORT=54321
				QEMU_GDBSERVER_VM_PORT=54321
				QEMU_SSH_HOST_PORT=5555


				$QEMU_AARCH64 \
				-kernel $LINUX_BUILD/arch/arm64/boot/Image \
				-M $QEMU_MACHINE \
				-cpu $QEMU_CPU \
				-machine type=$QEMU_MACHINE \
				-smp $QEMU_CORES \
				-m $QEMU_MEMORY \
				rovkaUnsubmitted Not Done Reply Inline Actions Nitpick: For Internet access [...] rovka: Nitpick: For Internet access [...]
				-drive file=$QEMU_RFS_IMG,index=0,media=disk,format=raw \
				-append "root=/dev/vda rw ip=dhcp mem=1024M raid=noautodetect \
				crashkernel=128M rootwait console=ttyAMA0 devtmpfs.mount=0" \
				-nographic \
				-net nic -net user \
				-nic user,hostfwd=tcp::$QEMU_GDBSERVER_HOST_PORT-:$QEMU_GDBSERVER_VM_PORT,hostfwd=tcp::$QEMU_SSH_HOST_PORT-:22

				###############################################################################
				# Your default username will be the one with whom you created RootFS image.
				# For internet access inside your emulation environment run: sudo dhclient enp0s2.
				################################################################################
				# Alternatively setup a tap device on host computer by following this link:
				# https://wiki.qemu.org/Documentation/Networking/NAT
				#
				# Run QEMU emulation using commandline given below:

				$QEMU_AARCH64 \
				-kernel $LINUX_BUILD/arch/arm64/boot/Image \
				-M $QEMU_MACHINE \
				-cpu $QEMU_CPU,sve-max-vq=$QEMU_SVE_MAX_VQ \
				-machine type=$QEMU_MACHINE \
				-smp $QEMU_CORES \
				-m $QEMU_MEMORY \
				-drive file=$QEMU_RFS_IMG,index=0,media=disk,format=raw \
				-append "root=/dev/vda rw ip=dhcp mem=1024M raid=noautodetect crashkernel=128M rootwait console=ttyAMA0 devtmpfs.mount=0" \
				-nographic \
				-net tap -net nic

				################################################################################
				# End of STEP 4
				################################################################################

				################################################################################
				# STEP 5
				# Running lldb-server in QEMU emulation environment
				################################################################################

				# Login emulation environment and install dependencies
				sudo apt install python-dev libedit-dev libncurses5-dev libexpat1-dev

				# Setup ssh access between host machine and emulation environment
				rovkaUnsubmitted Not Done Reply Inline Actions For consistency, maybe there should be some commands here, or a link to the docs for cross-compiling. rovka: For consistency, maybe there should be some commands here, or a link to the docs for cross…
				# Make sure br0 is enabled on host machine by running:
				ip add

				# Find out ip address assigned to eth0 in emulation environment
				ip add

				# Verify ssh access
				ssh username@ip-address-of-emulation-environment

				# Cross compile LLDB server for AArch64 Linux
				# Please visit https://lldb.llvm.org/resources/build.html for instructions
				# on how to cross compile LLDB server.

				# Transfer LLDB server executable to emulation environment
				scp lldb-server username@ip-address-of-emulation-environment:/home/username