[elrepo] kernel-lt and microcode updates

[Phil Perry]

On 19/06/2020 01:45, 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
> 

We can probably fix this by adding a %triggerin script to kernel-ml and 
kernel-lt packages to achieve the same thing.

%triggerin -- microcode_ctl
<script to update initramfs for elrepo kernels only>