alpine-qemu-arm.sh

wget http://dl-cdn.alpinelinux.org/alpine/v3.7/releases/armhf/alpine-uboot-3.7.0-armhf.tar.gz
wget http://dl-cdn.alpinelinux.org/alpine/v3.7/releases/armhf/alpine-minirootfs-3.7.0-armhf.tar.gz

qemu-img create -f raw sd.img 512M

sudo losetup /dev/loop0 sd.img 
sudo kpartx -av /dev/loop0
lsblk
sudo mkfs.ext4 /dev/mapper/loop0p1
mount -t ext4 /dev/mapper/loop0p1 /mnt

sudo cp alpine-minirootfs-3.7.0-armhf.tar.gz /mnt/
sudo cp alpine-uboot-3.7.0-armhf.tar.gz /mnt
sudo cd /mnt/
sudo tar xzvf alpine-minirootfs-3.7.0-armhf.tar.gz 
sudo tar xzvf alpine-uboot-3.7.0-armhf.tar.gz
sudo rm alpine-minirootfs-3.7.0-armhf.tar.gz
sudo rm alpine-uboot-3.7.0-armhf.tar.gz
sudo umount /mnt
sudo kpartx -dv /dev/loop0
sudo losetup -d /dev/loop0

file sd.img 
  #sd.img: DOS/MBR boot sector; partition 1 : ID=0x83, start-CHS (0x10,0,1), end-CHS (0x3ff,3,32), startsector 2048, 1046528 sectors
rm alpine-*
ls
  #alpine.apkovl.tar.gz  apks  boot  extlinux  sd.img  u-boot

qemu-system-arm -sd sd.img -m 256 -M vexpress-a9 -dtb boot/dtbs/vexpress-v2p-ca9.dtb -kernel boot/vmlinuz-hardened -initrd boot/initramfs-hardened -append "modules=loop,squashfs,sd-mod,usb-storage,ext4 modloop=/boot/modloop-hardened root=/dev/mmcblk0 console=ttyAMA0" -nographic

gistfile1.txt

martin@martin:~/lede$ qemu-system-arm -sd sd.img -m 256 -M vexpress-a9 -dtb boot/dtbs/vexpress-v2p-ca9.dtb -kernel boot/vmlinuz-hardened -initrd boot/initramfs-hardened -append "modules=loop,squashfs,sd-mod,usb-storage,ext4 modloop=/boot/modloop-hardened root=/dev/mmcblk0 console=ttyAMA0" -nographic
WARNING: Image format was not specified for 'sd.img' and probing guessed raw.
         Automatically detecting the format is dangerous for raw images, write operations on block 0 will be restricted.
         Specify the 'raw' format explicitly to remove the restrictions.
pulseaudio: set_sink_input_volume() failed
pulseaudio: Reason: Invalid argument
pulseaudio: set_sink_input_mute() failed
pulseaudio: Reason: Invalid argument
[    0.000000] Booting Linux on physical CPU 0x0
[    0.000000] Linux version 4.9.65-1-hardened (buildozer@build-3-7-armhf) (gcc version 6.4.0 (Alpine 6.4.0) ) #2-Alpine SMP Mon Nov 27 15:37:20 GMT 2017
[    0.000000] CPU: ARMv7 Processor [410fc090] revision 0 (ARMv7), cr=10c5387d
[    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT nonaliasing instruction cache
[    0.000000] OF: fdt:Machine model: V2P-CA9
[    0.000000] efi: Getting EFI parameters from FDT:
[    0.000000] efi: UEFI not found.
[    0.000000] Memory policy: Data cache writeback
[    0.000000] CPU: All CPU(s) started in SVC mode.
[    0.000000] percpu: Embedded 13 pages/cpu @8fd7a000 s23180 r8192 d21876 u53248
[    0.000000] Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 64960
[    0.000000] Kernel command line: modules=loop,squashfs,sd-mod,usb-storage,ext4 modloop=/boot/modloop-hardened root=/dev/mmcblk0 console=ttyAMA0
[    0.000000] log_buf_len individual max cpu contribution: 4096 bytes
[    0.000000] log_buf_len total cpu_extra contributions: 12288 bytes
[    0.000000] log_buf_len min size: 16384 bytes
[    0.000000] log_buf_len: 32768 bytes
[    0.000000] early log buf free: 14828(90%)
[    0.000000] PID hash table entries: 1024 (order: 0, 4096 bytes)
[    0.000000] Dentry cache hash table entries: 32768 (order: 5, 131072 bytes)
[    0.000000] Inode-cache hash table entries: 16384 (order: 4, 65536 bytes)
[    0.000000] Memory: 246072K/262144K available (4213K kernel code, 484K rwdata, 1828K rodata, 684K init, 349K bss, 16072K reserved, 0K cma-reserved, 0K highmem)
[    0.000000] Virtual kernel memory layout:
[    0.000000]     vector  : 0xffff0000 - 0xffff1000   (   4 kB)
[    0.000000]     fixmap  : 0xffc00000 - 0xfff00000   (3072 kB)
[    0.000000]     vmalloc : 0x90800000 - 0xff800000   (1776 MB)
[    0.000000]     lowmem  : 0x80000000 - 0x90000000   ( 256 MB)
[    0.000000]     pkmap   : 0x7fe00000 - 0x80000000   (   2 MB)
[    0.000000]     modules : 0x7f000000 - 0x7fe00000   (  14 MB)
[    0.000000]       .text : 0x80208000 - 0x80625694   (4214 kB)
[    0.000000]       .init : 0x80819000 - 0x808c4000   ( 684 kB)
[    0.000000]       .data : 0x808c4000 - 0x8093d360   ( 485 kB)
[    0.000000]        .bss : 0x8093d360 - 0x80994b48   ( 350 kB)
[    0.000000] SLUB: HWalign=64, Order=0-3, MinObjects=0, CPUs=4, Nodes=1
[    0.000000] Hierarchical RCU implementation.
[    0.000000] 	Build-time adjustment of leaf fanout to 32.
[    0.000000] NR_IRQS:16 nr_irqs:16 16
[    0.000000] GIC CPU mask not found - kernel will fail to boot.
[    0.000000] GIC CPU mask not found - kernel will fail to boot.
[    0.000000] L2C: platform modifies aux control register: 0x02020000 -> 0x02420000
[    0.000000] L2C: DT/platform modifies aux control register: 0x02020000 -> 0x02420000
[    0.000000] L2C-310 erratum 769419 enabled
[    0.000000] L2C-310 enabling early BRESP for Cortex-A9
[    0.000000] L2C-310 full line of zeros enabled for Cortex-A9
[    0.000000] L2C-310 dynamic clock gating disabled, standby mode disabled
[    0.000000] L2C-310 cache controller enabled, 8 ways, 128 kB
[    0.000000] L2C-310: CACHE_ID 0x410000c8, AUX_CTRL 0x46420001
[    0.000000] smp_twd: clock not found -2
[    0.000230] sched_clock: 32 bits at 24MHz, resolution 41ns, wraps every 89478484971ns
[    0.003377] clocksource: arm,sp804: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 1911260446275 ns
[    0.004027] Failed to initialize '/smb@04000000/motherboard/iofpga@7,00000000/timer@12000': -22
[    0.011244] Console: colour dummy device 80x30
[    0.011773] Calibrating local timer... 100.74MHz.
[    0.039056] Calibrating delay loop... 557.87 BogoMIPS (lpj=1394688)
[    0.074036] pid_max: default: 32768 minimum: 501
[    0.075833] Mount-cache hash table entries: 1024 (order: 0, 4096 bytes)
[    0.075891] Mountpoint-cache hash table entries: 1024 (order: 0, 4096 bytes)
[    0.089781] CPU: Testing write buffer coherency: ok
[    0.101231] CPU0: thread -1, cpu 0, socket 0, mpidr 80000000
[    0.101598] Setting up static identity map for 0x60208280 - 0x602082d8
[    0.114941] EFI services will not be available.
[    0.129741] Brought up 1 CPUs
[    0.129851] SMP: Total of 1 processors activated (557.87 BogoMIPS).
[    0.129924] CPU: All CPU(s) started in SVC mode.
[    0.138952] devtmpfs: initialized
[    0.159007] VFP support v0.3: implementor 41 architecture 3 part 30 variant 9 rev 0
[    0.178134] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 9556302231375000 ns
[    0.179111] futex hash table entries: 1024 (order: 4, 65536 bytes)
[    0.183681] pinctrl core: initialized pinctrl subsystem
[    0.213912] NET: Registered protocol family 16
[    0.216791] DMA: preallocated 256 KiB pool for atomic coherent allocations
[    0.293602] cpuidle: using governor ladder
[    0.293743] cpuidle: using governor menu
[    0.294731] hw-breakpoint: debug architecture 0x4 unsupported.
[    0.297406] Serial: AMBA PL011 UART driver
[    0.305487] OF: amba_device_add() failed (-19) for /memory-controller@100e0000
[    0.306663] OF: amba_device_add() failed (-19) for /memory-controller@100e1000
[    0.307140] OF: amba_device_add() failed (-19) for /watchdog@100e5000
[    0.309168] irq: type mismatch, failed to map hwirq-75 for /interrupt-controller@1e001000!
[    0.322932] 10009000.uart: ttyAMA0 at MMIO 0x10009000 (irq = 38, base_baud = 0) is a PL011 rev1
[    0.340336] console [ttyAMA0] enabled
[    0.345476] 1000a000.uart: ttyAMA1 at MMIO 0x1000a000 (irq = 39, base_baud = 0) is a PL011 rev1
[    0.349335] 1000b000.uart: ttyAMA2 at MMIO 0x1000b000 (irq = 40, base_baud = 0) is a PL011 rev1
[    0.354952] 1000c000.uart: ttyAMA3 at MMIO 0x1000c000 (irq = 41, base_baud = 0) is a PL011 rev1
[    0.358275] OF: amba_device_add() failed (-19) for /smb@04000000/motherboard/iofpga@7,00000000/wdt@0f000
[    0.406155] vgaarb: loaded
[    0.408464] pps_core: LinuxPPS API ver. 1 registered
[    0.408702] pps_core: Software ver. 5.3.6 - Copyright 2005-2007 Rodolfo Giometti <giometti@linux.it>
[    0.409146] PTP clock support registered
[    0.429862] clocksource: Switched to clocksource arm,sp804
[    0.434498] VFS: Disk quotas dquot_6.6.0
[    0.435045] VFS: Dquot-cache hash table entries: 1024 (order 0, 4096 bytes)
[    0.496930] NET: Registered protocol family 2
[    0.505223] TCP established hash table entries: 2048 (order: 1, 8192 bytes)
[    0.505642] TCP bind hash table entries: 2048 (order: 2, 16384 bytes)
[    0.506038] TCP: Hash tables configured (established 2048 bind 2048)
[    0.506939] UDP hash table entries: 256 (order: 1, 8192 bytes)
[    0.507345] UDP-Lite hash table entries: 256 (order: 1, 8192 bytes)
[    0.511104] NET: Registered protocol family 1
[    0.518669] Trying to unpack rootfs image as initramfs...
[    1.561867] Freeing initrd memory: 5468K
[    1.565170] hw perfevents: enabled with armv7_cortex_a9 PMU driver, 1 counters available
[    1.582019] workingset: timestamp_bits=14 max_order=16 bucket_order=2
[    1.601368] Key type asymmetric registered
[    1.601927] Block layer SCSI generic (bsg) driver version 0.4 loaded (major 249)
[    1.602203] io scheduler noop registered
[    1.603007] io scheduler cfq registered (default)
[    1.622258] pci_hotplug: PCI Hot Plug PCI Core version: 0.5
[    1.622763] pciehp: PCI Express Hot Plug Controller Driver version: 0.4
[    1.632049] Serial: 8250/16550 driver, 4 ports, IRQ sharing disabled
[    1.638411] Serial: AMBA driver
[    1.640074] msm_serial: driver initialized
[    1.716959] brd: module loaded
[    1.719889] libphy: Fixed MDIO Bus: probed
[    1.729984] gre: GRE over IPv4 demultiplexor driver
[    1.731043] Key type dns_resolver registered
[    1.731397] ThumbEE CPU extension supported.
[    1.731604] Registering SWP/SWPB emulation handler
[    1.734487] registered taskstats version 1
[    1.736373] hctosys: unable to open rtc device (rtc0)
[    1.741289] uart-pl011 10009000.uart: no DMA platform data
[    1.755620] Freeing unused kernel memory: 684K
[    1.755898] This architecture does not have kernel memory protection.
Alpine Init 3.2.0-r0
 * Loading boot drivers: [    2.461387] loop: module loaded
[    2.471253] squashfs: version 4.0 (2009/01/31) Phillip Lougher
[    2.502950] SCSI subsystem initialized
[    2.533771] usbcore: registered new interface driver usbfs
[    2.535033] usbcore: registered new interface driver hub
[    2.536868] usbcore: registered new device driver usb
[    2.545949] usbcore: registered new interface driver usb-storage
ok.
 * Mounting root: [    4.303452] clcd-pl11x 10020000.clcd: PL111 designer 41 rev2 at 0x10020000
[    4.325440] clcd-pl11x 10020000.clcd: /clcd@10020000 hardware, 1024x768@59 display
[    4.333813] clcd-pl11x 1001f000.clcd: PL111 designer 41 rev2 at 0x1001f000
[    4.341721] clcd-pl11x 1001f000.clcd: /smb@04000000/motherboard/iofpga@7,00000000/clcd@1f000 hardware, 640x480@59 display
[    4.428195] mmci-pl18x 10005000.mmci: Got CD GPIO
[    4.428529] mmci-pl18x 10005000.mmci: Got WP GPIO
[    4.436042] mmci-pl18x 10005000.mmci: mmc0: PL181 manf 41 rev0 at 0x10005000 irq 34,35 (pio)
[    4.436384] mmci-pl18x 10005000.mmci: DMA channels RX none, TX none
[    4.498974] mmc0: new SD card at address 4567
[    4.554596] mmcblk0: mmc0:4567 QEMU! 512 MiB 
[    4.575282]  mmcblk0: p1
[   14.121155] Console: switching to mono frame buffer device 128x48
[   14.592219] random: fast init done
[   15.005071] random: crng init done
mount: mounting /dev/mmcblk0 on /sysroot failed: Invalid argument
failed. 
initramfs emergency recovery shell launched. Type 'exit' to continue boot
sh: can't access tty; job control turned off
/ # 

I got here while doing Google searches so I guess other people will too.
Here's a script to create a 32-bit Alpine armv7 VM that works:
https://gist.github.com/ambiamber/4e70be9ae0c7ecbbdbd7880b36db59ca