[ovirt-users] Nested KVM - vdsm-hook-nestedvt

[Martin Polednik]

On 04/01/16 14:38 +0100, wdh at dds.nl wrote:
>Hi all,
>
>OK, it seems I am confused. Nested KVM is NOT the same as fake KVM....
>
>If so, I installed vdsm-hook-nestedvt on the hypervisor (only). Trying 
>to run ovirt-Node on a VM it complains there 's no virtualization, 
>despite the kvm_amd module is loaded with nested=1
>
>How to enable nested-kvm for oVirt 3.6?

First, make sure that you're enabling the nested feature for amd (just
noticed that the example used intel). Please show us the output of

# cat /sys/module/kvm_intel/parameters/nested

on the host (physical machine), lscpu inside the VM and VM XML - use

# virsh -r list
# virsh -r dumpxml {machine_id found in the list}

Thanks,
mpolednik

>Winny
>
>
>Martin Polednik schreef op 04-01-2016 13:29:
>>On 04/01/16 09:52 +0100, Simone Tiraboschi wrote:
>>>On Fri, Jan 1, 2016 at 3:32 PM, Winfried de Heiden <wdh at dds.nl> wrote:
>>>
>>>>Hi all and happy new year!
>>>>
>>>>I'm running oVirt 3.6 on EL7.
>>>>
>>>>In order to test nested-kvm I installed vdsm-hook-nestedvt on the
>>>>hypervisor and put "fake_kvm_support = true" in /etc/vdsm/vdsm.conf.
>>>
>>>
>>>
>>>
>>>fake_kvm_support is just for developing purposes and it's not 
>>>needed as it
>>>prevent guests to run.
>>
>>Not really true - fake_kvm_support enables QEMU emulation instead of
>>hardware virtualization (e.g. VT-x) instructions. It is also quite
>>broken in it's current state and fix is pending in cpuinfo branch at
>>gerrit.
>>
>>I don't really understand the reason why fake_kvm would be used in
>>this case as AMD-v is enabled according to svm flag present -
>>following instructions should be correct for getting the flag passed
>>to the VMs.
>>
>>>Please check to understand if nested support is enabled on your host:
>>>/sys/module/kvm_intel/parameters/nested
>>>
>>>if not
>>>  echo "options kvm-intel nested=1" > /etc/modprobe.d/kvm-intel.conf
>>>and reload the module
>>
>>>Than install vdsm-hook-nestedvt on your hosts.
>>>If you want also to use the network on your L2 guest please 
>>>install and
>>>configure also macspoof vdsm hook on your physical hosts otherwise 
>>>all the
>>>traffic to/from your L2 guests will be dropped.
>>>https://github.com/oVirt/vdsm/tree/master/vdsm_hooks/macspoof
>>>
>>>
>>>
>>>
>>>>However, afterwards the hypervisor host cannot connect to the ovirt
>>>>Manager, on ovirt Manager the engine.log will tell:
>>>>
>>>>2016-01-01 15:21:42,105 WARN
>>>>[org.ovirt.engine.core.dal.dbbroker.auditloghandling.AuditLogDirector]
>>>>(DefaultQuartzScheduler_Worker-76) [71d1638c] Correlation ID: 
>>>>29daf92c,
>>>>Call Stack: null, Custom Event ID: -1, Message: Host bigvirt moved to
>>>>Non-Operational state as host does not meet the cluster's minimum CPU
>>>>level. Missing CPU features : model_Opteron_G3
>>>>
>>>>After removing the option all works well again, but I'ḿ lacking 
>>>>the nested
>>>>kvm option :( Is nested kvm only supported on a limited cpu's??
>>>>
>>>>Winny
>>>>
>>>>Information from /proc/cpuinfo:
>>>>
>>>>processor       : 0
>>>>vendor_id       : AuthenticAMD
>>>>cpu family      : 16
>>>>model           : 10
>>>>model name      : AMD Phenom(tm) II X6 1055T Processor
>>>>stepping        : 0
>>>>microcode       : 0x10000bf
>>>>cpu MHz         : 2800.000
>>>>cache size      : 512 KB
>>>>physical id     : 0
>>>>siblings        : 6
>>>>core id         : 0
>>>>cpu cores       : 6
>>>>apicid          : 0
>>>>initial apicid  : 0
>>>>fpu             : yes
>>>>fpu_exception   : yes
>>>>cpuid level     : 6
>>>>wp              : yes
>>>>flags           : fpu vme de pse tsc msr pae mce cx8 apic sep 
>>>>mtrr pge mca
>>>>cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext 
>>>>fxsr_opt
>>>>pdpe1gb rdtscp lm 3dnowext 3dnow constant_tsc rep_good nopl 
>>>>nonstop_tsc
>>>>extd_apicid aperfmperf pni monitor cx16 popcnt lahf_lm cmp_legacy svm
>>>>extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs 
>>>>skinit wdt
>>>>cpb hw_pstate npt lbrv svm_lock nrip_save pausefilter
>>>>bogomips        : 5625.54
>>>>TLB size        : 1024 4K pages
>>>>clflush size    : 64
>>>>cache_alignment : 64
>>>>address sizes   : 48 bits physical, 48 bits virtual
>>>>power management: ts ttp tm stc 100mhzsteps hwpstate cpb
>>>>
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>>>>
>>
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