Comment 0 for bug 1329434

[Impact]
Using nested KVM on some hypervisors doesn't work.

[Test Case]
1) enable nested KVM:
sudo modprobe -r kvm_intel
sudo modprobe kvm_intel nested=1
cat /sys/module/kvm_intel/parameters/nested
# should say Y

2) generate an L1 guest and then generate an L2 guest inside the L1 guest
- ensure L1 has enough memory to boot L2
- if using libvirt you may need to edit the default bridge to use a different subnet than the L1 guest

3) boot the L2 guest
4) L2 guest should boot

If not you can see the log:
sudo cat /var/log/libvirt/qemu/nested-L2.log
<snip>
KVM: entry failed, hardware error 0x0
EAX=00000000 EBX=00000000 ECX=00000000 EDX=00000663
ESI=00000000 EDI=00000000 EBP=00000000 ESP=00000000
EIP=0000fff0 EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
ES =0000 00000000 0000ffff 00009300
CS =f000 ffff0000 0000ffff 00009b00
SS =0000 00000000 0000ffff 00009300
DS =0000 00000000 0000ffff 00009300
FS =0000 00000000 0000ffff 00009300
GS =0000 00000000 0000ffff 00009300
LDT=0000 00000000 0000ffff 00008200
TR =0000 00000000 0000ffff 00008b00
GDT= 00000000 0000ffff
IDT= 00000000 0000ffff
CR0=60000010 CR2=00000000 CR3=00000000 CR4=00000000
DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000 DR3=0000000000000000
DR6=00000000ffff0ff0 DR7=0000000000000400
EFER=0000000000000000
Code=00 66 89 d8 66 e8 02 f7 ff ff 66 83 c4 0c 66 5b 66 5e 66 c3 <ea> 5b e0 00 f0 30 36 2f 32 33 2f 39 39 00 fc 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00