CentOS 7 Newer Kernel Needed

Home » CentOS-Virt » CentOS 7 Newer Kernel Needed
CentOS-Virt 8 Comments

Hello,

I am looking for a Linux kernel for CentOS 7 that implements a feature introduced in kernel version 3.12:

“nested EPT support to KVM‘s nested VMX.”

If anyone has used this feature with CentOS 7, please let me know.

Laurentiu

8 thoughts on - CentOS 7 Newer Kernel Needed

  • Dear Laurentiu,

    Please check below info since assume your CentOS7 box CPU processor already VT supported in advance.

    1) Checkpoint #1: Hardware and Kernel modules

    a. cat /proc/cpuinfo | grep vmx

    b. cat /sys/module/kvm_intel/parameters/nested (if “N” then go to checkpoint #2)

    2) Checkpoint #2: Assume your CentOS box support

    a. echo ‘options kvm-intel nested=y’ >> /etc/modprobe.d/dist.conf b. modprobe kvm-intel

    3) Checkpoint #3: Verification

    a. Reboot yout CentOS box

    b. cat /sys/module/kvm_intel/parameters/nested (if “Y” then you can carry one process the KVM installation.

    PS: Source: https://lalatendu.org/2015/11/01/kvm-nested-virtualization-in-fedora-23/ which should be very similar with CentOS and CentOS 7 already capable with on with KVM Nested EPT with CPU pass-through options supported. Hope that helps & cheers!!

    Xlord

    From: CentOS-virt-bounces@CentOS.org [mailto:CentOS-virt-bounces@CentOS.org] On Behalf Of Laurentiu Soica Sent: Thursday, August 4, 2016 3:07 AM
    To: CentOS-virt@CentOS.org Subject: [CentOS-virt] CentOS 7 newer kernel needed

    Hello,

    I am looking for a Linux kernel for CentOS 7 that implements a feature introduced in kernel version 3.12:

    “nested EPT support to KVM’s nested VMX.”

    If anyone has used this feature with CentOS 7, please let me know.

    Laurentiu

  • Hello Xlord,

    The CPU does have VT support and I already have the nested KVM enabled.

    Checking the Linux Kernel release notes I saw that the nested kvm feature was implemented in 3.10 but he EPT support is in 3.12.

    So CentOS 7’s kernel which is 3.10 does have the EPT support? Is there a way to check that the EPT support is available in the kernel?

    Thank you, Laurentiu

  • ——=_NextPart_001_0002_01D1EE73.5D07B150
    Content-Type: text/plain;
    charset=”utf-8″
    Content-Transfer-Encoding: quoted-printable

    Dear Laurentiu,

    Assume your hardware does support Intel VT-x with EPT supported, I have also look into the kernel part for fun!

    Just quick look at CentOS 7 and installed a CentOS_7x_x64_build1511 @installation at minimum, below is my sharing and hope to help!

    1) CentOS Linux Kernel version: 3.10.0-327.e17.x86_64 SMP

    2) Kernel parameters which should be your requirement;

    a. Default “kvm-intel.ept=1” (refer to Kernel Archive “https://www.kernel.org/”)

    b.

    Xlord

    From: Laurentiu Soica [mailto:laurentiu@soica.ro]
    Sent: Thursday, August 4, 2016 2:41 PM
    To: -=X.L.O.R.D=- ; Discussion about the virtualization on CentOS
    Subject: Re: [CentOS-virt] CentOS 7 newer kernel needed

    Hello Xlord,

    The CPU does have VT support and I already have the nested KVM enabled.

    Checking the Linux Kernel release notes I saw that the nested kvm feature was implemented in 3.10 but he EPT support is in 3.12.

    So CentOS 7’s kernel which is 3.10 does have the EPT support? Is there a way to check that the EPT support is available in the kernel?

    Thank you,

    Laurentiu

    Dear Laurentiu,

    Please check below info since assume your CentOS7 box CPU processor already VT supported in advance.

    1) Checkpoint #1: Hardware and Kernel modules

    a. cat /proc/cpuinfo | grep vmx

    b. cat /sys/module/kvm_intel/parameters/nested (if “N” then go to checkpoint #2)

    2) Checkpoint #2: Assume your CentOS box support

    a. echo ‘options kvm-intel nested=y’ >> /etc/modprobe.d/dist.conf b. modprobe kvm-intel

    3) Checkpoint #3: Verification

    a. Reboot yout CentOS box

    b. cat /sys/module/kvm_intel/parameters/nested (if “Y” then you can carry one process the KVM installation.

    PS: Source: https://lalatendu.org/2015/11/01/kvm-nested-virtualization-in-fedora-23/ which should be very similar with CentOS and CentOS 7 already capable with on with KVM Nested EPT with CPU pass-through options supported. Hope that helps & cheers!!

    Xlord

    From: CentOS-virt-bounces@CentOS.org [mailto:CentOS-virt-bounces@CentOS.org ] On Behalf Of Laurentiu Soica Sent: Thursday, August 4, 2016 3:07 AM
    To: CentOS-virt@CentOS.org

    Subject: [CentOS-virt] CentOS 7 newer kernel needed

    Hello,

    I am looking for a Linux kernel for CentOS 7 that implements a feature introduced in kernel version 3.12:

    “nested EPT support to KVM’s nested VMX.”

    If anyone has used this feature with CentOS 7, please let me know.

    Laurentiu

    ——=_NextPart_001_0002_01D1EE73.5D07B150
    Content-Type: text/html;
    charset=”utf-8″
    Content-Transfer-Encoding: quoted-printable

  • ——=_NextPart_001_0008_01D1EE73.B27B2680
    Content-Type: text/plain;
    charset=”utf-8″
    Content-Transfer-Encoding: quoted-printable

    Dear Laurentiu,

    Could you please check if your CPU supported from /proc/cpuinfo and lscpu ?

    EPT supported

    Xlord

    From: -=X.L.O.R.D=- [mailto:xlord.sl@gmail.com]
    Sent: Thursday, August 4, 2016 5:12 PM
    To: ‘Laurentiu Soica’ ; ‘Discussion about the virtualization on CentOS’
    Subject: RE: [CentOS-virt] CentOS 7 newer kernel needed

    Dear Laurentiu,

    Assume your hardware does support Intel VT-x with EPT supported, I have also look into the kernel part for fun!

    Just quick look at CentOS 7 and installed a CentOS_7x_x64_build1511 @installation at minimum, below is my sharing and hope to help!

    1) CentOS Linux Kernel version: 3.10.0-327.e17.x86_64 SMP

    2) Kernel parameters which should be your requirement;

    a. Default “kvm-intel.ept=1” (refer to Kernel Archive “https://www.kernel.org/”)

    b.

    Xlord

    From: Laurentiu Soica [mailto:laurentiu@soica.ro]
    Sent: Thursday, August 4, 2016 2:41 PM
    To: -=X.L.O.R.D=- >; Discussion about the virtualization on CentOS >
    Subject: Re: [CentOS-virt] CentOS 7 newer kernel needed

    Hello Xlord,

    The CPU does have VT support and I already have the nested KVM enabled.

    Checking the Linux Kernel release notes I saw that the nested kvm feature was implemented in 3.10 but he EPT support is in 3.12.

    So CentOS 7’s kernel which is 3.10 does have the EPT support? Is there a way to check that the EPT support is available in the kernel?

    Thank you,

    Laurentiu

    Dear Laurentiu,

    Please check below info since assume your CentOS7 box CPU processor already VT supported in advance.

    1) Checkpoint #1: Hardware and Kernel modules

    a. cat /proc/cpuinfo | grep vmx

    b. cat /sys/module/kvm_intel/parameters/nested (if “N” then go to checkpoint #2)

    2) Checkpoint #2: Assume your CentOS box support

    a. echo ‘options kvm-intel nested=y’ >> /etc/modprobe.d/dist.conf b. modprobe kvm-intel

    3) Checkpoint #3: Verification

    a. Reboot yout CentOS box

    b. cat /sys/module/kvm_intel/parameters/nested (if “Y” then you can carry one process the KVM installation.

    PS: Source: https://lalatendu.org/2015/11/01/kvm-nested-virtualization-in-fedora-23/ which should be very similar with CentOS and CentOS 7 already capable with on with KVM Nested EPT with CPU pass-through options supported. Hope that helps & cheers!!

    Xlord

    From: CentOS-virt-bounces@CentOS.org [mailto:CentOS-virt-bounces@CentOS.org ] On Behalf Of Laurentiu Soica Sent: Thursday, August 4, 2016 3:07 AM
    To: CentOS-virt@CentOS.org

    Subject: [CentOS-virt] CentOS 7 newer kernel needed

    Hello,

    I am looking for a Linux kernel for CentOS 7 that implements a feature introduced in kernel version 3.12:

    “nested EPT support to KVM’s nested VMX.”

    If anyone has used this feature with CentOS 7, please let me know.

    Laurentiu

    ——=_NextPart_001_0008_01D1EE73.B27B2680
    Content-Type: text/html;
    charset=”utf-8″
    Content-Transfer-Encoding: quoted-printable

  • –089e0103e5603b773005393e1d50
    Content-Type: text/plain; charset=UTF-8
    Content-Transfer-Encoding: quoted-printable

    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/log/?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?

    Thank you, Laurentii

    –089e0103e5603b773005393e1d50
    Content-Type: text/html; charset=UTF-8
    Content-Transfer-Encoding: quoted-printable

    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. 
    What options do I have to get this commits on a CentOS 7 kernel? 

    Thank you, 
    Laurentii
    On Thu, Aug 4, 2016, 12:14 -=X.L.O.R.D=- <xlord.sl@gmail.com> wrote:

    Dear Laurentiu,

    Could you please check if your CPU supported from /proc/cpuinfo and lscpu ?

     

    EPT supported

    Xlord

     

    From: -=X.L.O.R.D=- [mailto:xlord.sl@gmail.com]
    Sent: Thursday, August 4, 2016 5:12 PM
    To: 'Laurentiu Soica' <laurentiu@soica.ro>; 'Discussion about the virtualization on CentOS' <CentOS-virt@CentOS.org>
    Subject: RE: [CentOS-virt] CentOS 7 newer kernel needed

     

    Dear Laurentiu,

    Assume your hardware does support Intel VT-x with EPT supported, I have also look into the kernel part for fun!

    Just quick look at CentOS 7 and installed a CentOS_7x_x64_build1511 @installation at minimum, below is my sharing and hope to help!

    1)      CentOS Linux Kernel version: 3.10.0-327.e17.x86_64 SMP

    2)      Kernel parameters which should be your requirement;

    a.     Default kvm-intel.ept=1 (refer to Kernel Archive https://www.kernel.org/)

    b.    

    Xlord

     

    From: Laurentiu Soica [mailto:laurentiu@soica.ro]

    Sent: Thursday, August 4, 2016 2:41 PM
    To: -=X.L.O.R.D=- <xlord.sl@gmail.com>; Discussion about the virtualization on CentOS <CentOS-virt@CentOS.org>

    Subject: Re: [CentOS-virt] CentOS 7 newer kernel needed

     

    Hello Xlord, 

     

    The CPU does have VT support and I already have the nested KVM enabled. 

     

    Checking the Linux Kernel release notes I saw that the nested kvm feature was implemented in 3.10 but he EPT support is in 3.12.

     

    So CentOS 7's kernel which is 3.10 does have the EPT support? Is there a way to check that the EPT support is available in the kernel? 

     

    Thank you, 

    Laurentiu

    On Thu, Aug 4, 2016, 06:04 -=X.L.O.R.D=- <xlord.sl@gmail.com> wrote:

    Dear Laurentiu,

    Please check below info since assume your CentOS7 box CPU processor already VT supported in advance.

    1)     Checkpoint #1: Hardware and Kernel modules

    a.     cat /proc/cpuinfo | grep vmx

    b.     cat /sys/module/kvm_intel/parameters/nested (if N then go to checkpoint #2)

    2)     Checkpoint #2: Assume your CentOS box support

    a.     echo 'options kvm-intel nested=y' >> /etc/modprobe.d/dist.conf
    b.     modprobe kvm-intel

    3)      Checkpoint #3: Verification

    a.       Reboot yout CentOS box

    b.     cat /sys/module/kvm_intel/parameters/nested (if Y then you can carry one process the KVM installation.
                   
    PS: Source: https://lalatendu.org/2015/11/01/kvm-nested-virtualization-in-fedora-23/ which should be very similar with CentOS and CentOS 7 already capable with on with KVM Nested EPT with CPU pass-through options supported. Hope that helps & cheers!!

    Xlord

     

    From: CentOS-virt-bounces@CentOS.org [mailto:CentOS-virt-bounces@CentOS.org] On Behalf Of Laurentiu Soica
    Sent: Thursday, August 4, 2016 3:07 AM
    To: CentOS-virt@CentOS.org
    Subject: [CentOS-virt] CentOS 7 newer kernel needed

     

    Hello,

    I am looking for a Linux kernel for CentOS 7 that implements a feature introduced in kernel version 3.12:

    "nested EPT support to KVM's nested VMX."

    If anyone has used this feature with CentOS 7, please let me know.

    Laurentiu

    –089e0103e5603b773005393e1d50

  • –sVxWDmbPf59MBWhimBqsAThJ5IotJOUwJ
    Content-Type: text/plain; charset=windows-1252
    Content-Transfer-Encoding: quoted-printable

    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

    –sVxWDmbPf59MBWhimBqsAThJ5IotJOUwJ

  • 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—

  • Hello,

    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, Laurentiu

LEAVE A COMMENT