[elrepo] kernel-lt and microcode updates

[Orion Poplawski]

On 6/18/20 6:45 PM, Akemi Yagi wrote:
> On Thu, Jun 18, 2020 at 9:33 AM Orion Poplawski <orion at nwra.com
> <mailto:orion at nwra.com>> wrote:
> 
>     Hello -
> 
>     I was poking around and noticed some differences in microcode output in dmesg
>     between the stock EL7 kernel and kernel-lt:
> 
>     dmesg-3.10.0-1127.10.1.el7.x86_64:
>     [    0.000000] microcode: microcode updated early to revision 0xd6, date =
>     2019-10-03
>     [    5.997673] microcode: sig=0x406e3, pf=0x80, revision=0xd6
>     [    5.998518] microcode: Microcode Update Driver: v2.01
>     <tigran at aivazian.fsnet.co.uk <mailto:tigran at aivazian.fsnet.co.uk>>, Peter
>     Oruba
>     [    0.000000] microcode: microcode updated early to revision 0xd6, date =
>     2019-10-03
>     [    6.035419] microcode: sig=0x406e3, pf=0x80, revision=0xd6
>     [    6.035503] microcode: Microcode Update Driver: v2.01
>     <tigran at aivazian.fsnet.co.uk <mailto:tigran at aivazian.fsnet.co.uk>>, Peter
>     Oruba
>     [   25.411983] microcode: updated to revision 0xdc, date = 2020-04-27
> 
>     dmesg-4.4.227-1.el7.elrepo.x86_64:
>     [    0.052043] SRBDS: Vulnerable: No microcode
>     [    0.052066] MDS: Vulnerable: Clear CPU buffers attempted, no microcode
>     [    1.807176] microcode: CPU0 sig=0x406e3, pf=0x80, revision=0xc6
>     [    1.807189] microcode: CPU1 sig=0x406e3, pf=0x80, revision=0xc6
>     [    1.807210] microcode: CPU2 sig=0x406e3, pf=0x80, revision=0xc6
>     [    1.807230] microcode: CPU3 sig=0x406e3, pf=0x80, revision=0xc6
>     [    1.807312] microcode: Microcode Update Driver: v2.01
>     <tigran at aivazian.fsnet.co.uk <mailto:tigran at aivazian.fsnet.co.uk>>, Peter
>     Oruba
> 
>     This leads me to believe that the microcode is not getting updated when using
>     the elrepo lt kernel.  Is that expected?
> 
>     Thanks,
> 
>        Orion
> 
> 
> Looks like the explanation is in the posttrans scriptlet of microcode_ctl.
> 
> rpm -q --scripts microcode_ctl
> 
> [quote]
> ...
> # For RPM selection, kernel flavours (like "debug" or "kdump" or "zfcp",
> # with only the former being relevant to x86 architecture) are a part or RPM
> # name; it's also a part of uname, with different separator used in RHEL 6/7
> # and RHEL 8.  RT kernel, however, is special, as "rt" is another part
> # of RPM name and it has its own versioning scheme both in NVR and uname.
> # And there's the kernel package split in RHEL 8, so one should look for *-core
> # and not the main package.
> pkgs="kernel kernel-debug kernel-rt kernel-rt-debug"
> ...
> [/quote]
> 
> Therefore, initramfs will not be regenerated for kernel-ml or kernel-lt.
> 
> By the way, the microcode file name as shown by the lsinitrd command is:
> 
> kernel/x86/microcode/GenuineIntel.bin (Intel)
> 
> or
> 
> kernel/x86/microcode/AuthenticAMD.bin (AMD)
> 
> Akemi

While this may be an issue when microcode_ctl updates come in, in this case
I've just installed kernel-lt on a system so the initramfs images should be fresh.

-- 
Orion Poplawski
Manager of NWRA Technical Systems          720-772-5637
NWRA, Boulder/CoRA Office             FAX: 303-415-9702
3380 Mitchell Lane                       orion at nwra.com
Boulder, CO 80301                 https://www.nwra.com/

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