Index: lldb/docs/lldb-qemu-aarch64-sve-howto.txt
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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
+AArch64 features like SVE, MTE, Pointer Authentication etc. This write can be
+used as reference to setup similar testing environment for other architectures
+supported by QEMU emulator.
+
+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
+################################################################################
+#!/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
+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
+#
+# 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
+
+# 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-
+
+
+################################################################################
+# 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 $QEMU_MEMORY \
+-drive file=$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
+# 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