Hi,

I've been using my core i5 6500 (skylake-client) for some time now to test oVirt on my machine.

However this is no longer the case.

I am using Fedora 32 as my base system with nested-kvm enabled, when I try to install oVirt 4.4 as HCI single node, I get an error in the last phase which consists of copying the VM-Manager to the engine volume and boot it.

It is the boot that causes the problem, I get an error about the CPU :

the CPU is incompatible with host CPU: Host CPU does not provide required features: mpx

This is the CPU part from virsh domcapabilities on my physical machine

<cpu>
   <mode name='host-passthrough' supported='yes'/>
   <mode name='host-model' supported='yes'>
     <model fallback='forbid'>Skylake-Client-IBRS</model>
     <vendor>Intel</vendor>
     <feature policy='require' name='ss'/>
     <feature policy='require' name='vmx'/>
     <feature policy='require' name='pdcm'/>
     <feature policy='require' name='hypervisor'/>
     <feature policy='require' name='tsc_adjust'/>
     <feature policy='require' name='clflushopt'/>
     <feature policy='require' name='umip'/>
     <feature policy='require' name='md-clear'/>
     <feature policy='require' name='stibp'/>
     <feature policy='require' name='arch-capabilities'/>
     <feature policy='require' name='ssbd'/>
     <feature policy='require' name='xsaves'/>
     <feature policy='require' name='pdpe1gb'/>
     <feature policy='require' name='invtsc'/>
     <feature policy='require' name='ibpb'/>
     <feature policy='require' name='amd-ssbd'/>
     <feature policy='require' name='skip-l1dfl-vmentry'/>
   </mode>
   <mode name='custom' supported='yes'>
     <model usable='yes'>qemu64</model>
     <model usable='yes'>qemu32</model>
     <model usable='no'>phenom</model>
     <model usable='yes'>pentium3</model>
     <model usable='yes'>pentium2</model>
     <model usable='yes'>pentium</model>
     <model usable='yes'>n270</model>
     <model usable='yes'>kvm64</model>
     <model usable='yes'>kvm32</model>
     <model usable='yes'>coreduo</model>
     <model usable='yes'>core2duo</model>
     <model usable='no'>athlon</model>
     <model usable='yes'>Westmere-IBRS</model>
     <model usable='yes'>Westmere</model>
     <model usable='no'>Skylake-Server-IBRS</model>
     <model usable='no'>Skylake-Server</model>
     <model usable='yes'>Skylake-Client-IBRS</model>
     <model usable='yes'>Skylake-Client</model>
     <model usable='yes'>SandyBridge-IBRS</model>
     <model usable='yes'>SandyBridge</model>
     <model usable='yes'>Penryn</model>
     <model usable='no'>Opteron_G5</model>
     <model usable='no'>Opteron_G4</model>
     <model usable='no'>Opteron_G3</model>
     <model usable='yes'>Opteron_G2</model>
     <model usable='yes'>Opteron_G1</model>
     <model usable='yes'>Nehalem-IBRS</model>
     <model usable='yes'>Nehalem</model>
     <model usable='yes'>IvyBridge-IBRS</model>
     <model usable='yes'>IvyBridge</model>
     <model usable='no'>Icelake-Server</model>
     <model usable='no'>Icelake-Client</model>
     <model usable='yes'>Haswell-noTSX-IBRS</model>
     <model usable='yes'>Haswell-noTSX</model>
     <model usable='yes'>Haswell-IBRS</model>
     <model usable='yes'>Haswell</model>
     <model usable='no'>EPYC-IBPB</model>
     <model usable='no'>EPYC</model>
     <model usable='no'>Dhyana</model>
     <model usable='yes'>Conroe</model>
     <model usable='no'>Cascadelake-Server</model>
     <model usable='yes'>Broadwell-noTSX-IBRS</model>
     <model usable='yes'>Broadwell-noTSX</model>
     <model usable='yes'>Broadwell-IBRS</model>
     <model usable='yes'>Broadwell</model>
     <model usable='yes'>486</model>
   </mode>
</cpu>

Here is the lscpu of my physical machine

# lscpu
Architecture:                    x86_64
CPU op-mode(s):                  32-bit, 64-bit
Byte Order:                      Little Endian
Address sizes:                   39 bits physical, 48 bits virtual
CPU(s):                          4
On-line CPU(s) list:             0-3
Thread(s) per core:              1
Core(s) per socket:              4
Socket(s):                       1
NUMA node(s):                    1
Vendor ID:                       GenuineIntel
CPU family:                      6
Model:                           94
Model name:                      Intel(R) Core(TM) i5-6500 CPU @ 3.20GHz
Stepping:                        3
CPU MHz:                         954.588
CPU max MHz:                     3600.0000
CPU min MHz:                     800.0000
BogoMIPS:                        6399.96
Virtualization:                  VT-x
L1d cache:                       128 KiB
L1i cache:                       128 KiB
L2 cache:                        1 MiB
L3 cache:                        6 MiB
NUMA node0 CPU(s):               0-3
Vulnerability Itlb multihit:     KVM: Mitigation: Split huge pages
Vulnerability L1tf:              Mitigation; PTE Inversion; VMX conditional cache flushes, SMT disabled
Vulnerability Mds:               Mitigation; Clear CPU buffers; SMT disabled
Vulnerability Meltdown:          Mitigation; PTI
Vulnerability Spec store bypass: Mitigation; Speculative Store Bypass disabled via prctl and seccomp
Vulnerability Spectre v1:        Mitigation; usercopy/swapgs barriers and __user pointer sanitization
Vulnerability Spectre v2:        Mitigation; Full generic retpoline, IBPB conditional, IBRS_FW, STIBP disabled, RSB filling
Vulnerability Srbds:             Vulnerable: No microcode
Vulnerability Tsx async abort:   Mitigation; Clear CPU buffers; SMT disabled
Flags:                           fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constan
                                t_tsc art arch_perfmon pebs bts rep_good nopl xtopology nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16
                                 xtpr pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_fault invpcid_single pti ssbd
                                 ibrs ibpb stibp tpr_shadow vnmi flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm mpx rdseed adx smap clflushopt in
                                tel_pt xsaveopt xsavec xgetbv1 xsaves dtherm ida arat pln pts hwp hwp_notify hwp_act_window hwp_epp md_clear flush_l1d

Here is the CPU part from virsh dumpxml of my ovirt hypervisor

<cpu mode='custom' match='exact' check='full'>
   <model fallback='forbid'>Skylake-Client-IBRS</model>
   <vendor>Intel</vendor>
   <feature policy='require' name='ss'/>
   <feature policy='require' name='vmx'/>
   <feature policy='require' name='pdcm'/>
   <feature policy='require' name='hypervisor'/>
   <feature policy='require' name='tsc_adjust'/>
   <feature policy='require' name='clflushopt'/>
   <feature policy='require' name='umip'/>
   <feature policy='require' name='md-clear'/>
   <feature policy='require' name='stibp'/>
   <feature policy='require' name='arch-capabilities'/>
   <feature policy='require' name='ssbd'/>
   <feature policy='require' name='xsaves'/>
   <feature policy='require' name='pdpe1gb'/>
   <feature policy='require' name='ibpb'/>
   <feature policy='require' name='amd-ssbd'/>
   <feature policy='require' name='skip-l1dfl-vmentry'/>
   <feature policy='disable' name='mpx'/>
</cpu>

Here is the lcpu of my ovirt hypervisor

[root@node1 ~]# lscpu
Architecture :                          x86_64
Mode(s) opératoire(s) des processeurs : 32-bit, 64-bit
Boutisme :                              Little Endian
Processeur(s) :                         4
Liste de processeur(s) en ligne :       0-3
Thread(s) par cœur :                    1
Cœur(s) par socket :                    1
Socket(s) :                             4
Nœud(s) NUMA :                          1
Identifiant constructeur :              GenuineIntel
Famille de processeur :                 6
Modèle :                                94
Nom de modèle :                         Intel Core Processor (Skylake, IBRS)
Révision :                              3
Vitesse du processeur en MHz :          3191.998
BogoMIPS :                              6383.99
Virtualisation :                        VT-x
Constructeur d'hyperviseur :            KVM
Type de virtualisation :                complet
Cache L1d :                             32K
Cache L1i :                             32K
Cache L2 :                              4096K
Cache L3 :                              16384K
Nœud NUMA 0 de processeur(s) :          0-3
Drapaux :                               fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ss syscall nx pdpe1gb rdtscp lm constant_tsc rep_go
od nopl xtopology cpuid tsc_known_freq pni pclmulqdq vmx ssse3 fma cx16 pdcm pcid sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm 3dnow
prefetch cpuid_fault invpcid_single pti ssbd ibrs ibpb stibp tpr_shadow vnmi flexpriority ept vpid fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm rdseed adx smap clflushopt xs
aveopt xsavec xgetbv1 xsaves arat umip md_clear arch_capabilities

it seems not all the flags are presented to the hypervisor especially the mpx which causes the error

Is there a workaround for this?

Regards.