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Bug 1809510 - libvirtd: error : virCPUx86UpdateLive:3110 : operation failed: guest CPU doesn't match specification: missing features: fxsr_opt [rhel-8.1.0.z]
Summary: libvirtd: error : virCPUx86UpdateLive:3110 : operation failed: guest CPU does...
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 8
Classification: Red Hat
Component: libvirt
Version: 8.1
Hardware: Unspecified
OS: Unspecified
high
high
Target Milestone: rc
: 8.0
Assignee: Jiri Denemark
QA Contact: jiyan
URL:
Whiteboard:
Depends On: 1804224
Blocks:
TreeView+ depends on / blocked
 
Reported: 2020-03-03 10:03 UTC by RHEL Program Management Team
Modified: 2022-11-14 09:44 UTC (History)
7 users (show)

Fixed In Version: libvirt-4.5.0-35.3.el8
Doc Type: Bug Fix
Doc Text:
Cause: Libvirt did not recognize some CPU features as supported by QEMU because of missing translation between QEMU and libvirt CPU names. Consequence: When starting a domain with such features explicitly disabled in CPU configuration libvirt would not ask QEMU to disable them. Depending on domain configuration the domain would either fail to start or start with an unexpected configuration. Fix: Libvirt translates CPU feature names fetched from QEMU in case they differ to make sure no feature is wrongly considered unsupported by QEMU. Result: All explicitly disabled CPU features known to QEMU are properly mentioned on QEMU command line and the domain is started with the requested configuration.
Clone Of: 1804224
Environment:
Last Closed: 2020-04-07 14:11:30 UTC
Type: ---
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2020:1358 0 None None None 2020-04-07 14:11:47 UTC

Comment 5 jiyan 2020-03-09 02:32:09 UTC 
Reproduced this bug with libvirt-4.5.0-35.2.module+el8.1.0+5256+4b9ab730.x86_64.
Verified this bug with libvirt-4.5.0-35.3.module+el8.1.0+5931+8897e7e1.x86_64.

Version:
libvirt-4.5.0-35.2.module+el8.1.0+5256+4b9ab730.x86_64
qemu-kvm-2.12.0-88.module+el8.1.0+5708+85d8e057.3.x86_64
kernel-4.18.0-147.el8.x86_64

Steps:
1. Preprare a shutdown VM with the following conf
# virsh domstate test81 
shut off

# virsh dumpxml test81 --inactive |grep "<domain t"
<domain type='qemu'>

# virsh dumpxml test81 --inactive |grep "<cpu" -A29
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>EPYC</model>
    <vendor>AMD</vendor>
    <feature policy='require' name='acpi'/>
    <feature policy='require' name='ss'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='require' name='erms'/>
    <feature policy='require' name='mpx'/>
    <feature policy='require' name='pcommit'/>
    <feature policy='require' name='clwb'/>
    <feature policy='require' name='pku'/>
    <feature policy='require' name='ospke'/>
    <feature policy='require' name='la57'/>
    <feature policy='require' name='3dnowext'/>
    <feature policy='require' name='3dnow'/>
    <feature policy='disable' name='vme'/>
    <feature policy='disable' name='fma'/>
    <feature policy='disable' name='avx'/>
    <feature policy='disable' name='f16c'/>
    <feature policy='disable' name='rdrand'/>
    <feature policy='disable' name='avx2'/>
    <feature policy='disable' name='rdseed'/>
    <feature policy='disable' name='sha-ni'/>
    <feature policy='disable' name='xsavec'/>
    <feature policy='disable' name='misalignsse'/>
    <feature policy='disable' name='3dnowprefetch'/>
    <feature policy='disable' name='osvw'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='fxsr_opt'/>
  </cpu>

2. Start VM and check the log
# virsh start test81 
error: Failed to start domain test81
error: operation failed: guest CPU doesn't match specification: missing features: fxsr_opt

# tail -f /var/log/libvirt/qemu/test81.log
2020-03-09T02:23:15.501270Z qemu-kvm: warning: TCG doesn't support requested feature: CPUID.80000001H:EDX.fxsr-opt [bit 25] 
2020-03-09T02:23:15.501943Z qemu-kvm: warning: TCG doesn't support requested feature: CPUID.80000001H:EDX.fxsr-opt [bit 25] 

3. Update libvirt and restart libvirtd
# yum update libvirt* -y

# systemctl restart libvirtd

# rpm -qa libvirt
libvirt-4.5.0-35.3.module+el8.1.0+5931+8897e7e1.x86_64

4. Start the VM again and check the qemu cmd line/active dumpxml
# virsh start test81 
Domain test81 started

# ps -ef |grep test81
-cpu EPYC,acpi=on,ss=on,hypervisor=on,erms=on,mpx=on,pcommit=on,clwb=on,pku=on,ospke=on,la57=on,3dnowext=on,3dnow=on,vme=off,fma=off,avx=off,f16c=off,rdrand=off,avx2=off,rdseed=off,sha-ni=off,xsavec=off,misalignsse=off,3dnowprefetch=off,osvw=off,topoext=off,fxsr-opt=off

# virsh dumpxml test81 | grep "<cpu" -A30
  <cpu mode='custom' match='exact' check='full'>
    <model fallback='forbid'>EPYC</model>
    <vendor>AMD</vendor>
    <feature policy='require' name='acpi'/>
    <feature policy='require' name='ss'/>
    <feature policy='require' name='hypervisor'/>
    <feature policy='require' name='erms'/>
    <feature policy='require' name='mpx'/>
    <feature policy='require' name='pcommit'/>
    <feature policy='require' name='clwb'/>
    <feature policy='require' name='pku'/>
    <feature policy='require' name='ospke'/>
    <feature policy='require' name='la57'/>
    <feature policy='require' name='3dnowext'/>
    <feature policy='require' name='3dnow'/>
    <feature policy='disable' name='vme'/>
    <feature policy='disable' name='fma'/>
    <feature policy='disable' name='avx'/>
    <feature policy='disable' name='f16c'/>
    <feature policy='disable' name='rdrand'/>
    <feature policy='disable' name='avx2'/>
    <feature policy='disable' name='rdseed'/>
    <feature policy='disable' name='sha-ni'/>
    <feature policy='disable' name='xsavec'/>
    <feature policy='disable' name='misalignsse'/>
    <feature policy='disable' name='3dnowprefetch'/>
    <feature policy='disable' name='osvw'/>
    <feature policy='disable' name='topoext'/>
    <feature policy='disable' name='fxsr_opt'/>
  </cpu>
Comment 7 errata-xmlrpc 2020-04-07 14:11:30 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2020:1358
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