Bug 1628468

Summary: No reliable way to detect that KVM is working
Product: Red Hat Enterprise Linux 7 Reporter: Richard W.M. Jones <rjones>
Component: qemu-kvm-rhevAssignee: Virtualization Maintenance <virt-maint>
Status: CLOSED NOTABUG QA Contact: Chao Yang <chayang>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 7.7CC: abologna, chayang, hannsj_uhl, juzhang, lvivier, michen, virt-maint
Target Milestone: rc   
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Hardware: Unspecified   
OS: Unspecified   
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Last Closed: 2018-09-13 10:13:31 UTC Type: Bug
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Bug Blocks: 1605071, 1628469    

Description Richard W.M. Jones 2018-09-13 07:42:27 UTC 
Description of problem:

libvirt currently tried to test if KVM is working by seeing if /dev/kvm
exists.  Unfortunately recent changes to the qemu-kvm-rhev package mean
/dev/kvm is always created.  This leads to bugs like:

https://bugzilla.redhat.com/show_bug.cgi?id=1605071

We need a way to test if KVM is available and working, preferably without
having to launch an actual guest to find out.

Version-Release number of selected component (if applicable):

All versions of qemu-kvm-rhev since this file was added:

$ cat /usr/lib/udev/rules.d/80-kvm.rules
KERNEL=="kvm", GROUP="kvm", MODE="0666", OPTIONS+="static_node=kvm"

Steps to Reproduce:

On a machine where KVM is broken (eg. nested P9), try doing:

  virsh capabilities

It will show that KVM is available.

Or try:

  libguestfs-test-tool
Comment 2 Andrea Bolognani 2018-09-13 10:13:31 UTC 
(In reply to Richard W.M. Jones from comment #0)
> We need a way to test if KVM is available and working, preferably without
> having to launch an actual guest to find out.

You're looking for the query-kvm QMP command, which has been
available in QEMU since basically forever.

The only issue with it is that libvirt is not reporting the data
correctly, but we already have Bug 1628469 for that, so closing
this one as NOTABUG.