[CentOS-devel] [Virt] Backport of a qemu fix for /dev/kvm permissions ?

David Moreau Simard

dms at redhat.com
Thu Aug 18 11:46:44 UTC 2016


To make a long story short, in certain circumstances, the /dev/kvm
file can sometimes have permissions that do not allow it to be used
properly [1].

This claims to have been fixed in qemu-2.3.0-1.fc22.
I was wondering if we should expect that fix to land in the
qemu-kvm-ev-2.3.0* packages provided by the virt SIG repo ?

I know for a fact the patch is not there (yet) right now:

(on Fedora):

$ rpm -q --scripts qemu-system-x86
postinstall scriptlet (using /bin/sh):
# Default /dev/kvm permissions are 660, we install a udev rule changing that
# to 666. However trying to trigger the re-permissioning via udev has been
# a neverending source of trouble, so we just force it with chmod. For
# more info see: https://bugzilla.redhat.com/show_bug.cgi?id=950436
chmod --quiet 666 /dev/kvm || :

(with latest qemu-kvm-ev from CentOS SIG repo):

$ rpm -qp --scripts qemu-kvm-ev-2.3.0-31.el7_2.16.1.x86_64.rpm
postinstall scriptlet (using /bin/sh):
# load kvm modules now, so we can make sure no reboot is needed.
# If there's already a kvm module installed, we don't mess with it
sh /etc/sysconfig/modules/kvm.modules &> /dev/null || :
    udevadm trigger --subsystem-match=misc --sysname-match=kvm --action=add || :



[1]: https://bugzilla.redhat.com/show_bug.cgi?id=950436

David Moreau Simard
Senior Software Engineer | Openstack RDO

dmsimard = [irc, github, twitter]

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