Bug 2225348

Summary: [RHEL8] Document that the Guest OS must support the vCPU model and features provided by the Host
Product: Red Hat Enterprise Linux 8 Reporter: Germano Veit Michel <gveitmic>
Component: DocumentationAssignee: Jiri Herrmann <jherrman>
Documentation sub component: default QA Contact: RHEL DPM <rhel-docs>
Status: CLOSED CURRENTRELEASE Docs Contact:
Severity: medium    
Priority: high CC: nanliu, radrao, rhel-docs
Version: 8.8Keywords: Documentation, FutureFeature
Target Milestone: rc   
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Hardware: All   
OS: Linux   
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Last Closed: 2023-08-07 13:27:02 UTC Type: Bug
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Germano Veit Michel 2023-07-25 03:59:09 UTC 
This is the RHEL8 version of BZ2225347

Document URL: 
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html/configuring_and_managing_virtualization/getting-started-with-virtualization-in-rhel-8_configuring-and-managing-virtualization#assembly_creating-virtual-machines_virt-getting-started

Section Number and Name: 
2.2. Creating virtual machines

Describe the issue: 

Assume the following scenario:

Host OS:  RHEL9, supports CPU models X Y Z from Vendor A
Guest OS: RHEL7, only supports CPU models X and Y from Vendor A

If the hardware has model Z (assume a newer model released after hardware enablement for RHEL7 finished), it is possible to configure the VM with a cpu-model of Z, or with host-model or passthrough, all of which will expose CPU features to the Guest OS that its OS may not be able to handle properly. This is not tested, and may produce undesired results.

Suggestions for improvement: 

Document that the Guest OS version must also support the CPU model and features defined in the Guest XML, when creating/editing a VM, not just the Host OS.

Certified CPUs by RHEL version can be found at https://catalog.redhat.com/hardware/search?type=Component|CPU%20Collection&p=1