[pve-devel] [PATCH] update target-x86_64.conf to rhel6.2 version

Alexandre DERUMIER aderumier at odiso.com
Wed Feb 1 10:10:11 CET 2012


I think the not supported flags are not exposed to guest

we could check flags support with

kvm -cpu cpumodel,check


But if you want live migrate between diffenrents cpu model hosts, you need to choose the lowest cpu model. 
If you start the vm on more recent server, it'll expose the flag in the vm, and when you 'll live migrate on a lower model with no supported flag, it'll crash.



exemple :

host (kvmtest) cpu:

processor       : 1
vendor_id       : GenuineIntel
cpu family      : 6
model           : 15
model name      : Intel(R) Xeon(R) CPU            5110  @ 1.60GHz
stepping        : 6
cpu MHz         : 1595.915
cache size      : 4096 KB
physical id     : 0
siblings        : 2
core id         : 1
cpu cores       : 2
apicid          : 1
initial apicid  : 1
fpu             : yes
fpu_exception   : yes
cpuid level     : 10
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx lm constant_tsc arch_perfmon pebs bts rep_good aperfmperf pni dtes64 monitor ds_cpl vmx tm2 ssse3 cx16 xtpr pdcm dca lahf_lm tpr_shadow
bogomips        : 3192.07
clflush size    : 64
cache_alignment : 64
address sizes   : 36 bits physical, 48 bits virtual
power management:


kvmtest:~# kvm -cpu qemu64,check
warning: host cpuid 0000_0001 lacks requested flag 'popcnt' [0x00800000]
warning: host cpuid 8000_0001 lacks requested flag 'abm' [0x00000020]
warning: host cpuid 8000_0001 lacks requested flag 'sse4a' [0x00000040]

guest cpu:

processor       : 1
vendor_id       : GenuineIntel
cpu family      : 6
model           : 2
model name      : QEMU Virtual CPU version 1.0
stepping        : 3
cpu MHz         : 1595.915
cache size      : 4096 KB
fpu             : yes
fpu_exception   : yes
cpuid level     : 4
wp              : yes
flags           : fpu de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pse36 clflush mmx fxsr sse sse2 syscall nx lm rep_good nopl pni cx16 hypervisor lahf_lm
bogomips        : 3191.83
clflush size    : 64
cache_alignment : 64
address sizes   : 40 bits physical, 48 bits virtual
power management:




kvmtest:~# kvm -cpu cpu64-rhel6,check
warning: host cpuid 0000_0001 lacks requested flag 'x2apic' [0x00200000]  (this one is special, as it's a emulated if hardware does not support it)
warning: host cpuid 8000_0001 lacks requested flag 'abm' [0x00000020]
warning: host cpuid 8000_0001 lacks requested flag 'sse4a' [0x00000040]
Could not initialize SDL(No available video device) - exiting


guest cpu:
processor       : 1
vendor_id       : GenuineIntel
cpu family      : 6
model           : 13
model name      : QEMU Virtual CPU version (cpu64-rhel6)
stepping        : 3
cpu MHz         : 1595.915
cache size      : 4096 KB
fpu             : yes
fpu_exception   : yes
cpuid level     : 4
wp              : yes
flags           : fpu de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pse36 clflush mmx fxsr sse sse2 syscall nx lm rep_good nopl pni cx16 x2apic hypervisor lahf_lm
bogomips        : 3191.83
clflush size    : 64
cache_alignment : 64
address sizes   : 40 bits physical, 48 bits virtual
power management:


kvmtest:~# kvm -cpu Westmere,check
warning: host cpuid 0000_0001 lacks requested flag 'sse4.1|sse4_1' [0x00080000]
warning: host cpuid 0000_0001 lacks requested flag 'sse4.2|sse4_2' [0x00100000]
warning: host cpuid 0000_0001 lacks requested flag 'x2apic' [0x00200000]
warning: host cpuid 0000_0001 lacks requested flag 'popcnt' [0x00800000]
warning: host cpuid 0000_0001 lacks requested flag 'aes' [0x02000000]

guest cpu:

processor       : 1
vendor_id       : GenuineIntel
cpu family      : 6
model           : 44
model name      : Westmere E56xx/L56xx/X56xx (Nehalem-C)
stepping        : 1
cpu MHz         : 1595.915
cache size      : 4096 KB
fpu             : yes
fpu_exception   : yes
cpuid level     : 11
wp              : yes
flags           : fpu de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 syscall nx lm constant_tsc rep_good nopl pni ssse3 cx16 x2apic hypervisor lahf_lm
bogomips        : 3191.83
clflush size    : 64
cache_alignment : 64
address sizes   : 40 bits physical, 48 bits virtual
power management:


----- Mail original ----- 

De: "Dietmar Maurer" <dietmar at proxmox.com> 
À: "Alexandre DERUMIER" <aderumier at odiso.com> 
Cc: pve-devel at pve.proxmox.com 
Envoyé: Mercredi 1 Février 2012 08:27:10 
Objet: RE: [pve-devel] [PATCH] update target-x86_64.conf to rhel6.2 version 

> We can add all the new models. 
> 
> For the old model, did we really need old models ? (486,pentium3 ?) 
> 
> maybe keep coreduo,core2duo,qemu64,qemu32 + new models ? 

What happens if one select new cpu type on old hardware? Are those features 
emulated then? What is I select Opteron_G3 on coreduo hardware? 

> 
> I don't know what is kvm32,kvm64. 

no idea. 

- Dietmar 



-- 

-- 




	
	Alexandre Derumier 
Ingénieur système 
e-mail : aderumier at odiso.com 
Tél : +33 (0)3 20 68 88 90 
Fax : +33 (0)3 20 68 90 81 
45 Bvd du Général Leclerc 
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