[Xen-devel] Is: cpuid creation of PV guests is not correct. Was:Re: [PATCH v6 00/10] vnuma introduction

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

> I.e., no matter how I pin the vcpus, the guest sees the 4 vcpus as if
> they were all SMT siblings, within the same core, sharing all cache
> levels.

My recollection was that the setting of these CPUID values is
tied in how the toolstack sees it - and since the toolstack
runs in the initial domain - that is where it picks this data up.

This problem had been discussed by Andrew Cooper at some point
(Hackathon? Emails? IRC?) and moved under the 'fix cpuid creation/parsing'.

I think that this issue should not affect Elena's patchset - 
as the vNUMA is an innocent bystander that gets affected by this.

As such changing the title.
> 
> This is not the case for dom0 where (I booted with dom0_max_vcpus=4 on
> the xen command line) I see this:
> 
> root@benny:~# lstopo
> Machine (422MB)
>   Socket L#0 + L3 L#0 (8192KB)
>     L2 L#0 (256KB) + L1 L#0 (32KB) + Core L#0
>       PU L#0 (P#0)
>       PU L#1 (P#1)
>     L2 L#1 (256KB) + L1 L#1 (32KB) + Core L#1
>       PU L#2 (P#2)
>       PU L#3 (P#3)
> 
> root@benny:~# lscpu
> Architecture:          x86_64
> CPU op-mode(s):        32-bit, 64-bit
> Byte Order:            Little Endian
> CPU(s):                4
> On-line CPU(s) list:   0-3
> Thread(s) per core:    2
> Core(s) per socket:    2
> Socket(s):             1
> Vendor ID:             GenuineIntel
> CPU family:            6
> Model:                 60
> Stepping:              3
> CPU MHz:               3591.780
> BogoMIPS:              7183.56
> Hypervisor vendor:     Xen
> Virtualization type:   none
> L1d cache:             32K
> L1i cache:             32K
> L2 cache:              256K
> L3 cache:              8192K
> 
> What am I doing wrong, or what am I missing?
> 
> Thanks and Regards,
> Dario
> 
> -- 
> <<This happens because I choose it to happen!>> (Raistlin Majere)
> -----------------------------------------------------------------
> Dario Faggioli, Ph.D, http://about.me/dario.faggioli
> Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)
> 



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