Comment 6 for bug 1618473

The kernel 4.4.0 from Ubuntu 16.04 [1] (along with the corresponding initramfs image [2])
boots just fine on the compute node in question when running qemu manually
*without specifying CPU capabilites*:

qemu-system-x86_64 -enable-kvm \
        -m 4096 \
        -hda xenial-tmp.qcow2 \
        -kernel xenial-server-cloudimg-amd64-vmlinuz-generic \
        -initrd xenial-server-cloudimg-amd64-initrd-generic \
        -append 'root=/dev/sda1 console=ttyS0 init=/bin/bash' \
        -machine pc-1.0,accel=kvm,usb=off \
        -rtc base=utc \
        -serial mon:stdio \
        -vga none -nographic

[ 2.336938] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x22985a87e67, max_idle_ns: 440795315743 ns
Begin: Loading essential drivers ... [ 33.255089] md: linear personality registered for level -1
[ 33.257775] md: multipath personality registered for level -4
[ 33.260461] md: raid0 personality registered for level 0
[ 33.263413] md: raid1 personality registered for level 1
[ 33.332011] raid6: sse2x1 gen() 9879 MB/s
[ 33.400007] raid6: sse2x1 xor() 7749 MB/s
[ 33.468006] raid6: sse2x2 gen() 12580 MB/s
[ 33.536006] raid6: sse2x2 xor() 8603 MB/s
[ 33.604006] raid6: sse2x4 gen() 14482 MB/s
[ 33.672006] raid6: sse2x4 xor() 9791 MB/s
[ 33.672408] raid6: using algorithm sse2x4 gen() 14482 MB/s
[ 33.672839] raid6: .... xor() 9791 MB/s, rmw enabled
[ 33.673255] raid6: using intx1 recovery algorithm
[ 33.675180] xor: measuring software checksum speed
[ 33.712005] prefetch64-sse: 15306.000 MB/sec
[ 33.752005] generic_sse: 14939.000 MB/sec
[ 33.752384] xor: using function: prefetch64-sse (15306.000 MB/sec)
[ 33.754373] async_tx: api initialized (async)
[ 33.764205] md: raid6 personality registered for level 6
[ 33.764648] md: raid5 personality registered for level 5
[ 33.765090] md: raid4 personality registered for level 4
[ 33.769554] md: raid10 personality registered for level 10

[1] http://cloud-images.ubuntu.com/xenial/current/unpacked/xenial-server-cloudimg-amd64-vmlinuz-generic
[2] http://cloud-images.ubuntu.com/xenial/current/unpacked/xenial-server-cloudimg-amd64-initrd-generic