[CentOS-virt] Xen 4.6.6-9 (with XPTI meltdown mitigation) packages making their way to centos-virt-xen-testing

I've built & tagged packages for CentOS 6 and 7 4.6.6-9, with XPTI "stage 1" Meltdown mitigation.

This will allow 64-bit PV guests to run safely (with a few caveats), but incurs a fairly significant slowdown for 64-bit PV guests on Intel boxes (including domain 0).

If you prefer using Vixen / Comet, you can turn it off by adding 'xpti=0' to your Xen command-line.

Detailed information can be found in the XSA-254 advisory:

https://xenbits.xen.org/xsa/advisory-254.html

Please test and report any issues you have. I'll probably tag then with -release tomorrow.

4.8 packages should be coming to buildlogs soon.

-George