[elrepo] kernel-lt and microcode updates

Orion Poplawski orion at nwra.com
Wed Jul 1 12:21:56 EDT 2020


On 6/30/20 4:11 PM, Phil Perry wrote:
> On 19/06/2020 16:33, Orion Poplawski wrote:
>> 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.
>>
> 
> Agreed. Are you sure that kernel-lt was installed after microcode_ctl? 
> You can always try reinstalling kernel-lt to test. Kernel-lt doesn't do 
> anything special, so should incorporate the latest microcode into it's 
> initramfs image.
> 
> The %triggerin fix for microcode_ctl updates has been finalised and 
> tested [1], and we are confident it should fix the issue. It will be in 
> the next releases of kernel-lt and kernel-ml for el7. We are currently 
> testing on el8 and expect to roll out there too shortly for kernel-ml 
> packages.
> 
> Phil

I just re-installed kernel-lt on my laptop:

# grep -i microcode dmesg-3.10.0-1127.13.1.el7.x86_64
[    0.000000] microcode: microcode updated early to revision 0xd6, date 
= 2020-04-27
[    0.021352] SRBDS: Mitigation: Microcode
[    1.542686] microcode: sig=0x806ea, pf=0x80, revision=0xd6
[    1.542918] microcode: Microcode Update Driver: v2.01 
<tigran at aivazian.fsnet.co.uk>, Peter Oruba

# grep -i microcode dmesg-4.4.228-2.el7.elrepo.x86_64
[    0.035312] SRBDS: Vulnerable: No microcode
[    0.992458] microcode: CPU0 sig=0x806ea, pf=0x80, revision=0xb4
[    0.992471] microcode: CPU1 sig=0x806ea, pf=0x80, revision=0xb4
[    0.992491] microcode: CPU2 sig=0x806ea, pf=0x80, revision=0xb4
[    0.992511] microcode: CPU3 sig=0x806ea, pf=0x80, revision=0xb4
[    0.992530] microcode: CPU4 sig=0x806ea, pf=0x80, revision=0xb4
[    0.992550] microcode: CPU5 sig=0x806ea, pf=0x80, revision=0xb4
[    0.992569] microcode: CPU6 sig=0x806ea, pf=0x80, revision=0xb4
[    0.992588] microcode: CPU7 sig=0x806ea, pf=0x80, revision=0xb4
[    0.992673] microcode: Microcode Update Driver: v2.01 
<tigran at aivazian.fsnet.co.uk>, Peter Oruba

and /proc/cpuinfo indicates that microcode is not updated

Orion

-- 
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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