(RHSA-2018:2258) Important: qemu-kvm-rhev security update

KVM (Kernel-based Virtual Machine) is a full virtualization solution for
Linux on a variety of architectures. The qemu-kvm-rhev packages provide the
user-space component for running virtual machines that use KVM in
environments managed by Red Hat products.

Security fix(es):

• An industry-wide issue was found in the way many modern microprocessor
  designs have implemented speculative execution of Load & Store instructions
  (a commonly used performance optimization). It relies on the presence of a
  precisely-defined instruction sequence in the privileged code as well as
  the fact that memory read from address to which a recent memory write has
  occurred may see an older value and subsequently cause an update into the
  microprocessor’s data cache even for speculatively executed instructions
  that never actually commit (retire). As a result, an unprivileged attacker
  could use this flaw to read privileged memory by conducting targeted cache
  side-channel attacks. (CVE-2018-3639)

Acknowledgements:

Red Hat would like to thank Ken Johnson (Microsoft Security Response Center)
and Jann Horn (Google Project Zero) for reporting this issue.

Note: This is the qemu-kvm-rhev side of the CVE-2018-3639 mitigation that
includes support for guests running on hosts with AMD processors.

For more details about the security issue(s), including the impact, a CVSS
score, and other related information, refer to the CVE page(s) listed in
the References section.