[Starlingx-discuss] Support IBRS cpu model.

Sun, Austin austin.sun at intel.com
Wed Nov 28 06:45:06 UTC 2018


Hi Chris and All:
     More info for Qemu to support IBRS. 
      Qemu 2.10  is used in StarlingX.  From [1] and [2],  Qemu 2.12.1 will start supporting spec-ctrl/IBRS chip support. 


[1] https://www.qemu.org/2018/02/14/qemu-2-11-1-and-spectre-update/
[2] https://wiki.qemu.org/ChangeLog/2.12 

Thanks.
BR
Austin Sun. 

-----Original Message-----
From: Sun, Austin 
Sent: Tuesday, November 27, 2018 5:18 PM
To: 'Chris Friesen' <chris.friesen at windriver.com>; starlingx-discuss at lists.starlingx.io
Subject: RE: [Starlingx-discuss] Support IBRS cpu model.

Hi Chris:
    Thanks your suggestion.   I have done some more test .  Here is the result. 

Compute CPU: Skylake-IBRS,
If we created VM with non-IBRS CPU model(Skylake-server, Broadwell etc),  it worked fine with patch. 
But when create VM with IBRS CPU model,  Qemu will report below error "2018-11-27T08:42:23.764924Z qemu-kvm: can't apply global Broadwell-x86_64-cpu.spec-ctrl=on: Property '.spec-ctrl' not found"
Or
"qemu-kvm: can't apply global Skylake-Server-x86_64-cpu.spec-ctrl=on: Property '.spec-ctrl' not found"

From link[1]:  it seems we have to upgrade qemu to check if we can fully support *IBRS cpu model.  
Currently we can only create non-IBRS CPU model or passthrough with those two patches [2] and [3]

 
[1] https://bugzilla.redhat.com/show_bug.cgi?id=1532401
[2] https://github.com/starlingx-staging/stx-nova/pull/17
[3] https://github.com/starlingx-staging/stx-glance/pull/5

Thanks.
BR
Austin Sun. 

-----Original Message-----
From: Chris Friesen [mailto:chris.friesen at windriver.com]
Sent: Friday, November 23, 2018 11:08 PM
To: Sun, Austin <austin.sun at intel.com>; starlingx-discuss at lists.starlingx.io
Subject: Re: [Starlingx-discuss] Support IBRS cpu model.

In order to ensure that we don't break existing code, I think we'd also need to test by booting VMs built using at least a flavor that specifies a different IBRS CPU model and a different non-IBRS CPU model.

Chris

On 11/23/2018 12:16 AM, Sun, Austin wrote:
> Hi Chris:
>      Due to resource limitation ,  I only deployed in Skylake-IBIS server , create VM enabling cpu-passthrough.
>   
> Thanks.
> BR
> Austin Sun.
> -----Original Message-----
> From: Chris Friesen [mailto:chris.friesen at windriver.com]
> Sent: Friday, November 23, 2018 1:42 AM
> To: Sun, Austin <austin.sun at intel.com>; 
> starlingx-discuss at lists.starlingx.io
> Subject: Re: [Starlingx-discuss] Support IBRS cpu model.
> 
> On 11/21/2018 11:46 PM, Sun, Austin wrote:
>> Hi Chris:
>>         Very appreciate your review
>> The new PRs are
>> https://github.com/starlingx-staging/stx-nova/pull/17
>> https://github.com/starlingx-staging/stx-glance/pull/5
> 
> What testing have you done on these changes?
> 
> Chris
> 



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