libvirt users - Jun 2017 - Way to detect virtual machine cpu features

Hello everyone

 I want to know how can I use libvirt to detect what cpu features a virtual
machine will see.

I guess I could do it in following way:

1. if cpu mode is 'custom', use 'virsh cpu-baseline --features'
on the cpu
model to get model features.
2. if cpu mode is 'host-passthrough' or 'host-model', do a
'virsh
capabilities' to list cpu features of physical host, they are identical to
features of virtual machine.

Is this right way to do things? Look forward to your valuable comments.

Best regards,
Lei

Hi, any comment or suggestion

On Thu, Jun 29, 2017 at 10:55 AM, Lei Zhang <lei12zhang12@gmail.com>
wrote:
> Hello everyone
>
>  I want to know how can I use libvirt to detect what cpu features a
> virtual machine will see.
>
> I guess I could do it in following way:
>
> 1. if cpu mode is 'custom', use 'virsh cpu-baseline
--features' on the
> cpu model to get model features.
> 2. if cpu mode is 'host-passthrough' or 'host-model', do a
'virsh
> capabilities' to list cpu features of physical host, they are identical
to
> features of virtual machine.
>
> Is this right way to do things? Look forward to your valuable comments.
>
> Best regards,
> Lei
>

Hi,

Am 2017-07-04 03:08, schrieb Lei Zhang:
> Hi, any comment or suggestion
> 
> On Thu, Jun 29, 2017 at 10:55 AM, Lei Zhang <lei12zhang12@gmail.com>
> wrote:
> 
>> Hello everyone
>> 
>> I want to know how can I use libvirt to detect what cpu features a
>> virtual machine will see.
>> 
>> I guess I could do it in following way:
>> 
>> 1. if cpu mode is 'custom', use 'virsh cpu-baseline
--features' on
>> the cpu model to get model features.
>> 2. if cpu mode is 'host-passthrough' or 'host-model',
do a 'virsh
>> capabilities' to list cpu features of physical host, they are
>> identical to features of virtual machine.
>> 
>> Is this right way to do things? Look forward to your valuable
>> comments.
>> 
>> Best regards,
>> Lei
> _______________________________________________
> libvirt-users mailing list
> libvirt-users@redhat.com
> https://www.redhat.com/mailman/listinfo/libvirt-users
why dont u fire up on 'host' & 'vm'  lscpu?

lscpu in vm on our server:

  # lscpu
Architecture:          x86_64
CPU op-mode(s):        32-bit, 64-bit
Byte Order:            Little Endian
CPU(s):                2
On-line CPU(s) list:   0,1
Thread(s) per core:    2
Core(s) per socket:    1
Socket(s):             1
NUMA node(s):          1
Vendor ID:             GenuineIntel
CPU family:            6
Model:                 60
Model name:            Intel Core Processor (Haswell)
Stepping:              4
CPU MHz:               3595.608
BogoMIPS:              7191.21
Hypervisor vendor:     KVM     
<========================================================================================
  Inside a VM !!!
Virtualization type:   full
L1d cache:             32K
L1i cache:             32K
L2 cache:              4096K
L3 cache:              16384K
NUMA node0 CPU(s):     0,1


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 rdtscp lm 
constant_tsc rep_good nopl xtopology pni pclmulqdq ssse3 fma cx16 pcid 
sse4_1 sse4_2 x2apic movbe popcnt tsc_deadline_timer aes xsave avx f16c 
rdrand hypervisor lahf_lm abm fsgsbase bmi1 hle avx2 smep bmi2 erms 
invpcid rtm xsaveopt arat

and there u see the cpu features.......



is this what u you want to see?


marko