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Bug 1840776

Summary:	cpu feature policy does not work as expected with host-passthrough and features supported by physical host
Product:	Red Hat Enterprise Linux Advanced Virtualization	Reporter:	jiyan <jiyan>
Component:	libvirt	Assignee:	Virtualization Maintenance <virt-maint>
Status:	CLOSED DUPLICATE	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	8.2	CC:	dyuan, jdenemar, jiyan, lmen, virt-maint, xuzhang, yalzhang
Target Milestone:	rc	Flags:	pm-rhel: mirror+
Target Release:	8.2
Hardware:	x86_64
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:	1840770	Environment:
Last Closed:	2020-05-27 19:38:41 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	1840770
Bug Blocks:

Description jiyan 2020-05-27 15:24:20 UTC

+++ This bug was initially created as a clone of Bug #1840770 +++

Description of problem:
cpu feature policy does not work as expected with host-passthrough and features supported by physical host

Version-Release number of selected component (if applicable):
libvirt-6.3.0-1.module+el8.3.0+6478+69f490bb.x86_64
qemu-kvm-5.0.0-0.module+el8.3.0+6620+5d5e1420.x86_64
kernel-4.18.0-202.el8.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Start VM with host-passthrough cpu conf, forbid policy and avx cpu feature (supported by the host) ==> Not expected here.
# lscpu | grep avx
Flags:               ... avx

# virsh domstate vm1 
shut off

# virsh dumpxml vm1 --inactive | grep "<cpu" -A2
  <cpu mode='host-passthrough' check='full'>
    <feature policy='forbid' name='avx'/>
  </cpu>

# virsh start vm1
Domain vm1 started

# ps -ef | grep vm1
-cpu host,avx=off 

Actual results:
As step-1 shows

Expected results:
VM should start failed like the following test scenario with host-model cpu conf.
1. Start VM with host-model cpu conf, forbid policy and avx cpu feature (supported by the host)
# lscpu | grep avx
Flags:               ... avx

# virsh domstate vm1 
shut off

# virsh dumpxml vm1 --inactive | grep "<cpu" -A2
  <cpu mode='host-model' check='full'>
    <feature policy='forbid' name='avx'/>
  </cpu>

# virsh start vm1
error: Failed to start domain vm1
error: operation failed: guest CPU doesn't match specification: missing features: mpx

Additional info:
Filed this bug because of https://bugzilla.redhat.com/show_bug.cgi?id=1515677#c13

Comment 1 Jiri Denemark 2020-05-27 19:38:41 UTC


*** This bug has been marked as a duplicate of bug 1840770 ***