我在2015年编写博文《从零使用qemu模拟器搭建arm运行环境》介绍在 Ubuntu 14.04系统如何一步步构造arm+qemu的运行环境。该文的主要问题是读者有运行环境不一定是Ubuntu 14.04，会遇到不少的软件包安装和编译错误问题，我也没有办法构造复现。另一方面，当前再次构造这个环境时，也会遇到类似的问题需要处理，特别是换成Centos发行版之后，处理起来更复杂。
既然每位朋友的发行版都不一样，那可以使用Docker统一构建环境，这是本项目的主要动机，使用Docker基于Ubuntu14.04镜像，再安装相应的软件包，一步步构建整个Linux kernel, busybox软件包，这样可以屏蔽构建环境的差异，同时也可以使用Dockerfile将整个过程自动化。
所以本项目利用容器技术，标准化构造环境，自动化构建整个过程，最后在容器内运行qemu+arm kernel。
完整的github目项：qemu-arm-linux.git
请参考Docker官方文档安装Docker软件：https://docs.docker.com/engine/install/
可以直接使用 yongting/arm-kernel-3.16-qemu:v1 这个镜像而跳过本步骤，直接从下个步骤开始操作。
git clone https://github.com/ivanalgo/qemu-arm-linux.git
直接运行下面命令:
# cd qemu-arm-linux # ./build-docker-image.sh构建成功后，请使用docker images来检查是否生成 arm-kernel-3.16-qemu 镜像
比如：
# docker images REPOSITORY TAG IMAGE ID CREATED SIZE arm-kernel-3.16-qemu latest db5c6750bbe4 About an hour ago 2.29GB ubuntu 14.04 df043b4f0cf1 2 weeks ago 197MB直接运行下面命令:
docker run -it --privileged arm-kernel-3.16-qemu /bin/bash 或者 docker run -it --privileged yongting/arm-kernel-3.16-qemu:v1 /bin/bash 从docker hub上直接利用我已发布的镜像。
# docker run -it --privileged arm-kernel-3.16-qemu /bin/bash root@bf121ecd02bd:/#在上面的容器里运行：/opt/create_image.sh 直创建给qemu使用磁盘，里面包含qemu+arm系统需要的rootfs，过程如下所示：
root@bf121ecd02bd:/# /opt/create_image.sh 32+0 records in 32+0 records out 33554432 bytes (34 MB) copied, 0.0122017 s, 2.7 GB/s mke2fs 1.42.9 (4-Feb-2014) /opt/a9rootfs.ext3 is not a block special device. Proceed anyway? (y,n) Discarding device blocks: done Filesystem label= OS type: Linux Block size=1024 (log=0) Fragment size=1024 (log=0) Stride=0 blocks, Stripe width=0 blocks 8192 inodes, 32768 blocks 1638 blocks (5.00%) reserved for the super user First data block=1 Maximum filesystem blocks=33554432 4 block groups 8192 blocks per group, 8192 fragments per group 2048 inodes per group Superblock backups stored on blocks: 8193, 24577 Allocating group tables: done Writing inode tables: done Creating journal (4096 blocks): done Writing superblocks and filesystem accounting information: done在上面的容器里运行：/opt/start_qemu.sh 运行启动一个qemu+arm系统，直接进入命令对arm linux进行命令操作，过程如下：
root@bf121ecd02bd:/# /opt/start_qemu.sh Booting Linux on physical CPU 0x0 Initializing cgroup subsys cpuset Linux version 3.16.0 (root@65f68ac08fad) (gcc version 4.7.3 (Ubuntu/Linaro 4.7.3-12ubuntu1) ) #1 SMP Wed Oct 7 10:26:41 UTC 2020 CPU: ARMv7 Processor [410fc090] revision 0 (ARMv7), cr=10c53c7d CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache Machine model: V2P-CA9 Memory policy: Data cache writeback CPU: All CPU(s) started in SVC mode. PERCPU: Embedded 7 pages/cpu @9fbcf000 s7552 r8192 d12928 u32768 Built 1 zonelists in Zone order, mobility grouping on. Total pages: 130048 Kernel command line: root=/dev/mmcblk0 console=ttyAMA0 PID hash table entries: 2048 (order: 1, 8192 bytes) Dentry cache hash table entries: 65536 (order: 6, 262144 bytes) Inode-cache hash table entries: 32768 (order: 5, 131072 bytes) Memory: 513116K/524288K available (4563K kernel code, 190K rwdata, 1288K rodata, 247K init, 150K bss, 11172K reserved) Virtual kernel memory layout: vector : 0xffff0000 - 0xffff1000 ( 4 kB) fixmap : 0xffc00000 - 0xffe00000 (2048 kB) vmalloc : 0xa0800000 - 0xff000000 (1512 MB) lowmem : 0x80000000 - 0xa0000000 ( 512 MB) modules : 0x7f000000 - 0x80000000 ( 16 MB) .text : 0x80008000 - 0x805bf0a0 (5853 kB) .init : 0x805c0000 - 0x805fdd80 ( 248 kB) .data : 0x805fe000 - 0x8062dac0 ( 191 kB) .bss : 0x8062dac8 - 0x806532e8 ( 151 kB) SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1 Hierarchical RCU implementation. RCU restricting CPUs from NR_CPUS=8 to nr_cpu_ids=4. RCU: Adjusting geometry for rcu_fanout_leaf=16, nr_cpu_ids=4 NR_IRQS:16 nr_irqs:16 16 GIC CPU mask not found - kernel will fail to boot. GIC CPU mask not found - kernel will fail to boot. L2C: platform modifies aux control register: 0x02020000 -> 0x02420000 L2C: device tree omits to specify unified cache L2C: DT/platform modifies aux control register: 0x02020000 -> 0x02420000 L2C-310 enabling early BRESP for Cortex-A9 L2C-310 full line of zeros enabled for Cortex-A9 L2C-310 dynamic clock gating disabled, standby mode disabled L2C-310 cache controller enabled, 8 ways, 128 kB L2C-310: CACHE_ID 0x410000c8, AUX_CTRL 0x46420001 sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 178956969942ns Console: colour dummy device 80x30 Calibrating delay loop... 895.79 BogoMIPS (lpj=4478976) pid_max: default: 32768 minimum: 301 Mount-cache hash table entries: 1024 (order: 0, 4096 bytes) Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes) CPU: Testing write buffer coherency: ok CPU0: thread -1, cpu 0, socket 0, mpidr 80000000 Setting up static identity map for 0x60454520 - 0x60454578 CPU1: failed to boot: -38 CPU2: failed to boot: -38 CPU3: failed to boot: -38 Brought up 1 CPUs SMP: Total of 1 processors activated. CPU: All CPU(s) started in SVC mode. devtmpfs: initialized VFP support v0.3: implementor 41 architecture 3 part 30 variant 9 rev 0 regulator-dummy: no parameters NET: Registered protocol family 16 DMA: preallocated 256 KiB pool for atomic coherent allocations cpuidle: using governor ladder cpuidle: using governor menu of_amba_device_create(): amba_device_add() failed (-19) for /memory-controller@100e0000 of_amba_device_create(): amba_device_add() failed (-19) for /memory-controller@100e1000 of_amba_device_create(): amba_device_add() failed (-19) for /watchdog@100e5000 of_amba_device_create(): amba_device_add() failed (-19) for /smb/motherboard/iofpga@7,00000000/sysctl@01000 of_amba_device_create(): amba_device_add() failed (-19) for /smb/motherboard/iofpga@7,00000000/wdt@0f000 hw-breakpoint: debug architecture 0x0 unsupported. Serial: AMBA PL011 UART driver 10009000.uart: ttyAMA0 at MMIO 0x10009000 (irq = 37, base_baud = 0) is a PL011 rev1 console [ttyAMA0] enabled 1000a000.uart: ttyAMA1 at MMIO 0x1000a000 (irq = 38, base_baud = 0) is a PL011 rev1 1000b000.uart: ttyAMA2 at MMIO 0x1000b000 (irq = 39, base_baud = 0) is a PL011 rev1 1000c000.uart: ttyAMA3 at MMIO 0x1000c000 (irq = 40, base_baud = 0) is a PL011 rev1 3V3: 3300 mV SCSI subsystem initialized usbcore: registered new interface driver usbfs usbcore: registered new interface driver hub usbcore: registered new device driver usb Advanced Linux Sound Architecture Driver Initialized. Switched to clocksource arm,sp804 NET: Registered protocol family 2 TCP established hash table entries: 4096 (order: 2, 16384 bytes) TCP bind hash table entries: 4096 (order: 3, 32768 bytes) TCP: Hash tables configured (established 4096 bind 4096) TCP: reno registered UDP hash table entries: 256 (order: 1, 8192 bytes) UDP-Lite hash table entries: 256 (order: 1, 8192 bytes) NET: Registered protocol family 1 RPC: Registered named UNIX socket transport module. RPC: Registered udp transport module. RPC: Registered tcp transport module. RPC: Registered tcp NFSv4.1 backchannel transport module. hw perfevents: enabled with ARMv7 Cortex-A9 PMU driver, 1 counters available futex hash table entries: 1024 (order: 4, 65536 bytes) squashfs: version 4.0 (2009/01/31) Phillip Lougher jffs2: version 2.2. (NAND) © 2001-2006 Red Hat, Inc. 9p: Installing v9fs 9p2000 file system support msgmni has been set to 1002 io scheduler noop registered (default) clcd-pl11x: probe of 10020000.clcd failed with error -22 clcd-pl11x: probe of 1001f000.clcd failed with error -22 VD10: at 1000 mV VD10_S2: at 1000 mV VD10_S3: at 1000 mV VCC1V8: at 1800 mV DDR2VTT: at 900 mV VCC3V3: at 3300 mV VIO: at 3300 mV 40000000.flash: Found 2 x16 devices at 0x0 in 32-bit bank. Manufacturer ID 0x000000 Chip ID 0x000000 NOR chip too large to fit in mapping. Attempting to cope... Intel/Sharp Extended Query Table at 0x0031 Using buffer write method Reducing visibility of 131072KiB chip to 65536KiB 40000000.flash: Found 2 x16 devices at 0x0 in 32-bit bank. Manufacturer ID 0x000000 Chip ID 0x000000 NOR chip too large to fit in mapping. Attempting to cope... Intel/Sharp Extended Query Table at 0x0031 Using buffer write method Reducing visibility of 131072KiB chip to 65536KiB Concatenating MTD devices: (0): "40000000.flash" (1): "40000000.flash" into device "40000000.flash" libphy: smsc911x-mdio: probed smsc911x 4e000000.ethernet eth0: attached PHY driver [Generic PHY] (mii_bus:phy_addr=4e000000.etherne:01, irq=-1) smsc911x 4e000000.ethernet eth0: MAC Address: 52:54:00:12:34:56 nxp-isp1760 4f000000.usb: NXP ISP1760 USB Host Controller nxp-isp1760 4f000000.usb: new USB bus registered, assigned bus number 1 nxp-isp1760 4f000000.usb: Scratch test failed. nxp-isp1760 4f000000.usb: can't setup: -19 nxp-isp1760 4f000000.usb: USB bus 1 deregistered usbcore: registered new interface driver usb-storage mousedev: PS/2 mouse device common for all mice rtc-pl031 10017000.rtc: rtc core: registered pl031 as rtc0 mmci-pl18x 10005000.mmci: Got CD GPIO #244. mmci-pl18x 10005000.mmci: Got WP GPIO #245. mmci-pl18x 10005000.mmci: No vqmmc regulator found mmci-pl18x 10005000.mmci: mmc0: PL181 manf 41 rev0 at 0x10005000 irq 41,42 (pio) ledtrig-cpu: registered to indicate activity on CPUs usbcore: registered new interface driver usbhid usbhid: USB HID core driver mmc0: new SD card at address 4567 mmcblk0: mmc0:4567 QEMU! 32.0 MiB mmcblk0: unknown partition table aaci-pl041 10004000.aaci: ARM AC'97 Interface PL041 rev0 at 0x10004000, irq 43 aaci-pl041 10004000.aaci: FIFO 512 entries oprofile: using arm/armv7-ca9 TCP: cubic registered NET: Registered protocol family 17 9pnet: Installing 9P2000 support rtc-pl031 10017000.rtc: setting system clock to 2020-10-07 11:47:19 UTC (1602071239) ALSA device list: #0: ARM AC'97 Interface PL041 rev0 at 0x10004000, irq 43 input: AT Raw Set 2 keyboard as /devices/smb/smb:motherboard/smb:motherboard:iofpga@7,00000000/10006000.kmi/serio0/input/input0 input: ImExPS/2 Generic Explorer Mouse as /devices/smb/smb:motherboard/smb:motherboard:iofpga@7,00000000/10007000.kmi/serio1/input/input2 kjournald starting. Commit interval 5 seconds EXT3-fs (mmcblk0): mounted filesystem with writeback data mode VFS: Mounted root (ext3 filesystem) readonly on device 179:0. Freeing unused kernel memory: 244K (805c0000 - 805fd000) random: nonblocking pool is initialized Please press Enter to activate this console. / # ls bin etc linuxrc proc usr dev lib lost+found sbin欢迎到github上提issue，也可以发起request，RP也一样欢迎。
