Re: [libvirt] [PATCH] apparmor: fix vfio usage without initial hostdev

On Mon, 2018-06-11 at 13:52 +0200, Christian Ehrhardt wrote: > The base vfio has not much functionality but to provide a custom > container by opening this path. > See https://www.kernel.org/doc/Documentation/vfio.txt for more. > > Systems with static hostdevs will get /dev/vfio/vfio by virt-aa- > hotplug > right from the beginning. But if the guest initially had no hostdev > at > all it will run into the following deny before the security module > labelling callbacks will make the actual vfio device (like > /dev/vfio/93) > known. > > Access by qemu is "wr" even thou in theory it could maybe be "r": > [ 2652.756712] audit: type=1400 audit(1491303691.719:25): > apparmor="DENIED" operation="open" > profile="libvirt-17a61b87-5132-497c-b928-421ac2ee0c8a" > name="/dev/vfio/vfio" pid=8486 comm="qemu-system-x86" > requested_mask="wr" denied_mask="wr" fsuid=64055 ouid=0 > > Bug-Ubuntu: https://bugs.launchpad.net/bugs/1678322 > Bug-Ubuntu: https://bugs.launchpad.net/bugs/1775777 > > Signed-off-by: Christian Ehrhardt <christian.ehrhardt(a)canonical.com&gt; > Signed-off-by: Stefan Bader <stefan.bader(a)canonical.com&gt; > --- > examples/apparmor/libvirt-qemu | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/examples/apparmor/libvirt-qemu > b/examples/apparmor/libvirt-qemu > index 2c47652250..874aca2092 100644 > --- a/examples/apparmor/libvirt-qemu > +++ b/examples/apparmor/libvirt-qemu > @@ -193,6 +193,9 @@ > deny /dev/shm/lttng-ust-wait-* r, > deny /run/shm/lttng-ust-wait-* r, > > + # for vfio hotplug on systems without static vfio (LP: #1775777) > + /dev/vfio/vfio rw, > + Makes sense. If the guest doesn't start with vfio then libvirtd is going to have to give it to the guest and so libvirtd would need this access. +1 to apply. -- Jamie Strandboge | http://www.canonical.com