RHBA-2016:2803 - Bug Fix Advisory

Topic

Updated qemu-kvm-rhev packages that fix two bugs and add one enhancement are now available for Red Hat Enterprise Virtualization Hypervisor 7.

Description

KVM (Kernel-based Virtual Machine) is a full virtualization solution for Linux on AMD64 and Intel 64 systems. The qemu-kvm-rhev packages provide the user-space component for running virtual machines using KVM in environments managed by Red Hat Enterprise Virtualization Manager.

This update fixes the following bugs:

• The fix for CVE-2016-5403 caused migrating guest instances to fail with a "Virtqueue size exceeded" error message. With this update, the value of the virtualization queue is recalculated after the migration, and the described problem no longer occurs. (BZ#1374623)
• Due to a race condition in the virtio-blk dataplane, live migration of a guest in some cases failed with a "Virtqueue size exceeded" error message. This update prevents the race condition from occurring, and thus allows live migration to work more reliably. (BZ#1380320)

In addition, this update adds the following enhancement:

• It is now possible to specify the virtio data buffer limit between a guest and the QEMU emulator. To do this, change the value of the <driver rx_queue_size='N'/> parameter in the guest's domain XML file, where N can be from 256 to 1024. (BZ#1375642)

Users of qemu-kvm-rhev are advised to upgrade to these updated packages, which fix these bugs. After installing this update, shut down all running virtual machines. Once all virtual machines have shut down, start them again for this update to take effect.

Solution

Before applying this update, make sure all previously released errata
relevant to your system have been applied.

For details on how to apply this update, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Virtualization 4 for RHEL 7 x86_64
• Red Hat Virtualization 3 for RHEL 7 x86_64
• Red Hat Virtualization for IBM Power LE 4 for RHEL 7 ppc64le
• Red Hat Virtualization for IBM Power LE 3 ppc64le

Fixes

• BZ - 1374623 - RHSA-2016-1756 breaks migration of instances
• BZ - 1380310 - match the OEM ID and OEM Table ID fields of the FADT and the RSDT to those of the SLIC [7.2.z]
• BZ - 1380320 - Race condition during virtio-blk dataplane stop triggers "Virtqueue size exceeded"

CVEs

(none)

References

(none)