As you probably know by now, three critical architectural flaws in CPUs have been recently disclosed that allow user processes to read kernel or hypervisor memory through cache side-channel attacks. These flaws, collectively named Meltdown and Spectre, affect in one way or another almost all processors that perform out-of-order execution, including x86 (from Intel and AMD), POWER, s390 and ARM processors.

A previous post detailed how QEMU/KVM might be affected by Spectre/Meltdown attacks, and what the plan was to mitigate them in QEMU 2.11.1 (and eventually QEMU 2.12).