[CentOS-devel] Need a knob to disable all spectre/meltdown fixes

[Young, Gregory]

Nipur,

Your best bet is to file a Feature Request in the Red Hat Bugzilla: https://bugzilla.redhat.com/. You will want to file it against RHEL 7 and tag it as kernel. If/when Red Hat implements it in the kernel source, it will be compiled for CentOS 7.


Greg



From: CentOS-devel <centos-devel-bounces at centos.org> On Behalf Of Priya, Nupur
Sent: February 25, 2019 11:19 PM
To: centos-devel at centos.org
Cc: Singh, Alok <Alok.Singh at harman.com>; Bhutani, Sudhanshu <Sudhanshu.Bhutani at Harman.com>
Subject: [CentOS-devel] Need a knob to disable all spectre/meltdown fixes

Hi there,
I would like to implement a command , to be able to disable all variants(or at least the ones causing performance impact). As per the RH article: https://access.redhat.com/articles/3311301, we would be able to only disable spectre variant 2 and 3(pti).

I need an option to disable variant 1, 3a and 4 as well. Some of the recent articles suggest that options like no_spectre_v1, no_spectre_v2 and spec_store_bypass_disable parameters are available in latest versions of kernel(4.15 and above).

https://www.zdnet.com/article/linux-kernel-gets-another-option-to-disable-spectre-mitigations/
https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html?highlight=kernel%20parameters

Can this be made available in our Centos 7 kernels? Or is there any plan for RH to implement the same in any future release?

Regards,
Nupur
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