	Xvisor on Allwinner A10 board (or Sun4i) using SD Booting 

This section of readme explains how to build & run Xvisor on actual Allwinner
A10 boards (Hackberry or pcduino for example) using SD booting feature of
Sun4i SOC.

By default, Xvisor for Sun4i supports Realview-PB-A8 guest so we will show
how to run Basic Firmware (and/or Linux) on Realview-PB-A8 guest.

As first step of SD booting on Sun4i SOC, we need to re-partition and program
a SD card (> 4GB card) with Uboot. For detailed info on preparing SD card for
booting refer: http://rhombus-tech.net/allwinner_a10/a10_mmc_boot

Once we have SD card prepared for SD booting, we add 3 images to the data
partition of SD card:
 1) U-Boot compatible Xvisor binary (uvmm.bin)
 2) DTB for Xvisor (sun4i-a10-hackberry.dtb)
 3) Disk image containing guest binaries (disk.img)

Following are steps to create these images and then boot Xvisor on Allwinner
A10:

  [1. Build environment]
  # export CROSS_COMPILE=arm-linux-gnueabi-

  [2. GoTo Xvisor source directory]
  # cd <xvisor_source_directory>

  [3. Initialize Xvisor submodules]
  # git submodule init
  # git submodule update
  (Note: This is required to be done only once in freshly cloned xvisor source)

  [4. Configure Xvisor with Generic-v7 default settings]
  # make ARCH=arm generic-v7-defconfig

  [5. Build Xvisor and DTBs]
  # make

  [6. Make U-Boot compatible uvmm.bin for use with bootm command]
  # mkimage -A arm -O linux -T kernel -C none -a 0x40008000 -e 0x40008000 -n Xvisor -d build/vmm.bin build/uvmm.bin

  [7. Build Basic Firmware]
  # make -C tests/arm32/realview-pb-a8/basic

  [8. Copy defconfig to Linux build directory]
  # cp tests/arm32/realview-pb-a8/linux/linux-<linux_version>_defconfig <linux_build_directory>/.config

  [9. GoTo Linux source directory]
  # cd <linux_source_directory>

  [10. Configure Linux in build directory]
  # sed -i 's/0xff800000UL/0xff000000UL/' arch/arm/include/asm/pgtable.h
  # make O=<linux_build_directory> ARCH=arm oldconfig

  [11. Build Linux in build directory]
  # make O=<linux_build_directory> ARCH=arm Image dtbs

  [12. Patch Linux kernel to replace sensitive non-priviledged instructions]
  # <xvisor_source_directory>/arch/arm/cpu/arm32/elf2cpatch.py -f <linux_build_directory>/vmlinux | <xvisor_source_directory>/build/tools/cpatch/cpatch32 <linux_build_directory>/vmlinux 0

  [13. Extract patched Linux kernel image]
  # ${CROSS_COMPILE}objcopy -O binary <linux_build_directory>/vmlinux <linux_build_directory>/arch/arm/boot/Image

  [14. Create BusyBox RAMDISK to be used as RootFS for Linux kernel]
  (Note: For subsequent steps, we will assume that your RAMDISK is located at <busybox_rootfs_directory>/rootfs.img)
  (Note: Please refer tests/common/busybox/README.md for creating rootfs.img using BusyBox)

  [15. GoTo Xvisor source directory]
  # cd <xvisor_source_directory>

  [16. Create disk image for Xvisor with Guest Linux and Guest Basic Firmware]
  # mkdir -p ./build/disk/tmp
  # mkdir -p ./build/disk/system
  # cp -f ./docs/banner/roman.txt ./build/disk/system/banner.txt
  # cp -f ./docs/logo/xvisor_logo_name.ppm ./build/disk/system/logo.ppm
  # mkdir -p ./build/disk/images/arm32/realview-pb-a8
  # ./build/tools/dtc/bin/dtc -I dts -O dtb -o ./build/disk/images/arm32/realview-pb-a8.dtb ./tests/arm32/realview-pb-a8/realview-pb-a8.dts
  # cp -f ./build/tests/arm32/realview-pb-a8/basic/firmware.bin.patched ./build/disk/images/arm32/realview-pb-a8/firmware.bin
  # cp -f ./tests/arm32/realview-pb-a8/linux/nor_flash.list ./build/disk/images/arm32/realview-pb-a8/nor_flash.list
  # cp -f ./tests/arm32/realview-pb-a8/linux/cmdlist ./build/disk/images/arm32/realview-pb-a8/cmdlist
  # cp -f ./tests/arm32/realview-pb-a8/xscript/one_guest_pb-a8.xscript ./build/disk/boot.xscript
  # cp -f <linux_build_directory>/arch/arm/boot/Image ./build/disk/images/arm32/realview-pb-a8/Image
  # cp -f <linux_build_directory>/arch/arm/boot/dts/arm-realview-pba8.dtb ./build/disk/images/arm32/realview-pb-a8/arm-realview-pba8.dtb
  # cp -f <busybox_rootfs_directory>/rootfs.img ./build/disk/images/arm32/rootfs.img
  # genext2fs -B 1024 -b 32768 -d ./build/disk ./build/disk.img
  OR
  [16. Create disk image for Xvisor with only Guest Basic Firmware]
  # mkdir -p ./build/disk/tmp
  # mkdir -p ./build/disk/system
  # cp -f ./docs/banner/roman.txt ./build/disk/system/banner.txt
  # cp -f ./docs/logo/xvisor_logo_name.ppm ./build/disk/system/logo.ppm
  # mkdir -p ./build/disk/images/arm32/realview-pb-a8
  # ./build/tools/dtc/bin/dtc -I dts -O dtb -o ./build/disk/images/arm32/realview-pb-a8.dtb ./tests/arm32/realview-pb-a8/realview-pb-a8.dts
  # cp -f ./build/tests/arm32/realview-pb-a8/basic/firmware.bin.patched ./build/disk/images/arm32/realview-pb-a8/firmware.bin
  # cp -f ./tests/arm32/realview-pb-a8/basic/nor_flash.list ./build/disk/images/arm32/realview-pb-a8/nor_flash.list
  # cp -f ./tests/arm32/realview-pb-a8/xscript/one_guest_pb-a8.xscript ./build/disk/boot.xscript
  # genext2fs -B 1024 -b 32768 -d ./build/disk ./build/disk.img

  [17. Make U-boot compatible initrd for use with bootm command]
  # mkimage -A arm -O linux -T ramdisk -a 0x41000000 -n "Xvisor ramdisk" -d build/disk.img build/udisk.img

  [18. Unplug bootable SD card from the A10 board and plug it on your development machine]

  [19. Mount data partition (or partition 2) of SD card on your development machine]

  [20. Copy uvmm.bin to data partition of SD card]
  # cp -f build/uvmm.bin <path_to_mounted_data_partition_of_sd_card>
  # cp -f build/arch/arm/board/generic/dts/allwinner/sun4i-a10-hackberry.dtb <path_to_mounted_data_partition_of_sd_card>
  # cp -f build/udisk.img <path_to_mounted_data_partition_of_sd_card>

  [21. Unmount data partition (or partition 2) of SD card from your development machine]

  [22. Unplug SD card from your development machine and plug it back on A10 board]

  [23. Connect to serial port of A10 board using Putty or Minicom]

  [24. Power-up or Reset A10 board and press any key when U-Boot shows auto-boot count down]

  [25. Enable MMC interface from U-Boot command line]
  sun4i# mmc dev 0:0

  [26. Copy Xvisor from SD card to SDRAM]
  sun4i# ext4load mmc 0:2 0x40200000 uvmm.bin

  [27. Copy Xvisor DTB from SD card to SDRAM]
  sun4i# ext4load mmc 0:2 0x40800000 sun4i-a10-hackberry.dtb

  [28. Copy disk image from SD card to SDRAM]
  sun4i# ext4load mmc 0:2 0x42000000 udisk.img

  [29. Jump into Xvisor after disabling MMU, interrupts, etc]
  sun4i# bootm 0x40200000 0x42000000 0x40800000

  [30. Kick Guest0 for starting Basic Firmware]
  Xsor# guest kick guest0

  [31. Bind to virtual UART]
  XVisor# vserial bind guest0/uart0

  [32. Try few commands of Basic firmware or goto next step]
  [guest0/uart0] basic# hi
  [guest0/uart0] basic# hello
  [guest0/uart0] basic# help

  [33. Copy linux from NOR flash to RAM and start linux booting from RAM]
  [guest0/uart0] basic# autoexec
  (Note: "autoexec" is a short-cut command)
  (Note: The <xvisor_source_directory>/tests/arm32/realview-pb-a8/linux/cmdlist
   file which we have added to guest NOR flash contains set of commands for booting
   linux from NOR flash)

  [34. Wait for Linux prompt to come-up and then try out some commands]
  [guest0/uart0] / # ls

  [35. Enter character seqence 'ESCAPE+x+q" return to Xvisor prompt]
  [guest0/uart0] / #

  (Note: replace all <> brackets based on your workspace)
  (Note: some of the above steps will need to be adapted for other
   types of ARM host)
  (Note: for more info on your desired ARM host refer docs/arm/)
  (Note: you are free to change the ordering of above steps based
   on your workspace)
