[CentOS-virt] Centos 7 newer kernel needed

Fri Aug 5 06:47:17 UTC 2016
Laurentiu Soica <laurentiu at soica.ro>


OK.  Thank you both for answering.  I have enough information now to decide
next if a kernel upgrade is required in my case or not.

I think the decision will be based on whether the 2nd level of
virtualization performs fast enough and without issues.

Have a great day,

On Fri, Aug 5, 2016, 08:32 -=X.L.O.R.D=- <xlord.sl at gmail.com> wrote:

> Dear Laurentiu,
> Agree with Johnny for kernel upgrade if upgrade helps, alternative if 3.10
> or above already supported it, you can check from kernel parameter or
> options if they are disabled on purpose.
> You can do that via the "make menuconfig" via
> "https://wiki.centos.org/HowTos/I_need_the_Kernel_Source" or
> "https://wiki.centos.org/HowTos/BuildingKernelModules". Hope that helps!
> Xlord
> -----Original Message-----
> From: centos-virt-bounces at centos.org [mailto:
> centos-virt-bounces at centos.org]
> On Behalf Of Johnny Hughes
> Sent: Thursday, August 4, 2016 9:10 PM
> To: centos-virt at centos.org
> Subject: Re: [CentOS-virt] Centos 7 newer kernel needed
> On 08/04/2016 07:30 AM, Laurentiu Soica wrote:
> > Hi Xlord,
> >
> > Yes,  the CPU has support for EPT.
> >
> > I wrongly thought that the nested EPT was first introduced in 3.12.
> > Following your instructions I see that I have it enabled on my system
> > as well.
> >
> > However,  checking the kernel commits from 3.12 on search string
> > 'nested ept'  I found about 10 code changes/fixes for nested EPT.
> >
> > https://git.kernel.org/cgit/linux/kernel/git/stable/linux-stable.git/l
> > og/?id=refs%2Ftags%2Fv3.12.62&qt=grep&q=Nested+ept
> >
> > What options do I have to get this commits on a Centos 7 kernel?
> The Standard CentOS kernel is built from the source code and configuration
> files of the released RHEL kernel.  The only way to get things into the
> main
> CentOS kernel is for it to be in the RHEL source code.
> Red Hat does backport changes into the RHEL kernel, so if they support
> nested those changes or ones like it may be there.  See Backporting:
> https://access.redhat.com/security/updates/backporting
> We do have a CentOSPlus kernel, maintained by a volunteer (hi toracat).
> She will take potential patches here if you have something that works:
> https://bugs.centos.org/view.php?id=6828
> Also, if you want to try a newer kernel, we do have 2 available.  I manage
> both of these kernels, they are both based on an LTS version of the kernel
> from kernel.org .. but neither gets nearly the attention (or smart people
> looking at them) as the RHEL based kernel.  If you want to try either of
> them, they are in:
> 3.18.x LTS:
> http://mirror.centos.org/centos/7/virt/x86_64/xen-46/
> 4.4.x LTS:
> http://mirror.centos.org/altarch/7.2.1511/experimental/x86_64/Packages/
> Those kernels both work, I am running both on production machines .. but I
> am not a kernel hacker, so I just build what the upstream LTS kernel
> maintainer releases.  They may or may not do what you want.
> The RHEL kernel team does a lot of work to make sure the RHEL kernel
> Thanks,
> Johnny Hughes
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