I'm still rooting for KVM because it has the best hardware compatibility, it in mainline and its performance is the best. However the security situation with QEMU is not as rosy as some of you portray it (and its not as bad as it looks either). The average customer/user is going to look at the number of QEMU CVEs on cvedetails and compare them to the number of Xen's and go with the latter. However most of the QEMU bugs only affect legacy emulated hardware or components not enabled in a KVM guest, most won't think that far.

It would clear things up if you have a table on your site showing which QEMU vulnerabilties affect a specified default configuration of a RHEL/Debian guest out of the box in libvirt. See this for example: https://www.qubes-os.org/security/xsa/

What I want to see:

* Adoption of QEMU-lite as the default mode for Linux guests. There's no point to running Linux in almost any emulated hardware.

* A builtin monitoring solution like Google has that detects excessive DRAM bitflips [1] and cache misses [2] and terminates the guests to foil rowhammer and covert channel attacks.

* A re-design of KSM thats not prone to rowhammer abuse [3]

*

[1] https://cloudplatform.googleblog.com/2017/01/7-ways-we-harde...

[2] https://www.usenix.org/system/files/conference/usenixsecurit...

[3] http://www.cs.vu.nl/~kaveh/pubs/pdf/ffs-usenixsec16.pdf