Contributor
Contributor

Upgrade ESXI 7.0.1 - Fatal CPU mismatch

I try to ugprade my homelab ESXi 7.0.0 (Build 16324942) to ESXi 7.0.1 (Build 17168206) and receive the attached purple screen after rebooting the host. The CPU used is an INTEL Atom C2750 which should be still supported according the HCL.

Any ideas?Screenshot 2020-11-30 at 18.30.26.png

 

best regards

Martin

 

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9 Replies
Expert
Expert

Hi @kolibri76 

Kindly check VMware Compatibility Guide 

If you think your queries have been answered
Marking this response as "Solution " or "Kudo"
ASAJM
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VMware Employee
VMware Employee

Hi @kolibri76 ,

CPU seems to be compatible with 7.0 and 7.0.1 per VMware HCL. This could be due to other system hardware or  a CPU feature that is not supported. It's worth checking the hardware BIOS for any such features.

If rollback option is provided, try rolling back to original version and try upgrading to 7.0 instead of 7.0.1 to see if it reports similar issues.

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Contributor
Contributor

Hi @ashilkrishnan 

Thank you for your help! The automatic rollback to 7.0 works (requires just a reboot). And 7.0 runs without a problem.

For what exact feature in the hardware BIOS should I look for? I must admit I have no idea, about what to check and where I can see if there is an incompatibility.

 

look forward for your response.

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Virtuoso
Virtuoso

From the error it looks like cores 1 through 7 returned a different value for a register than that for core 0. Most likely this is a CPUID instruction call or a read of a MSR for CPU features. I don't know why core 0 would have a different reading from cores 1 though 7.

Fatal CPU mismatch on feature "Intel processor platform type identifier"; cpu7 value = 0x1004195c, but cpu0 value = 0x10041a5c

Basically two bits were flipped. 0x9 = binary 1001 while 0xa is binary 1010

After rolling back to ESXi 7.0, is the microcode still version 0x12d? It might be a microcode/BIOS update problem somehow didn't cover all cores.

I think you can check microcode level from ESXi command line or from a vmware.log of any VM and look for ucode.

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Contributor
Contributor

@bluefirestorm 

Yes, current microcode version is 0x12d for all cores. But there is a difference between cpu0 and cpu1-7

[root@xxxxx:~] vsish -e cat /hardware/cpu/cpuList/0 | grep -i -E 'family|model|stepping|microcode|revision'

   Family:0x06 

   Model:0x4d 

   Stepping:0x08 

   Number of microcode updates:1

   Original Revision:0x00000121

   Current Revision:0x0000012d

[root@xxxxx:~] vsish -e cat /hardware/cpu/cpuList/1 | grep -i -E 'family|model|stepping|microcode|revision'

   Family:0x06 

   Model:0x4d 

   Stepping:0x08 

   Number of microcode updates:0

   Original Revision:0x0000012d

   Current Revision:0x0000012d

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Contributor
Contributor

Any news abaout this fatal CPU mismatch.

I have the same with my Atom homelab and the atom CPU is on HCL.

Regards, Steffen

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Contributor
Contributor

I am experiencing the same issue - Intel Atom C2758 - Verified on HCL - 7.0 has been working fine - Upgrade to 7.0.1 via vCenter fails with similar purple screen. 

 

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Contributor
Contributor

I have opened a ticket at Supermicro too. They would look at the Microcode, but maybe it is a problem of the ESXi query but nobody from VMware explain something about this message ...

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Contributor
Contributor

I tried taking the latest BIOS from Supermicro on a test machine in the lab, but the microcode still differs between core 0 and 1-7. 

Every C2700 series machine I've checked also has this microcode behavior, so I'm guessing that its going to get acknowledged as a bug.  These processor is extremely common and HCL for vSphere 7, so I'm guessing we will see a patch soon.

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