Re: [libvirt-users] Question about disabling '3dnowprefetch' CPU feature in Xen Guest using libvirt

Dear All, I'm reaching this mail-list to ask a small question about disabling '3dnowprefetch' CPU feature in Xen Guest using libvirt. This is my environment: Fedora release 26 (Twenty Six) 4.11.0-0.rc3.git0.2.fc26.x86_64 xen-4.8.1-2.fc26.x86_64 libvirt-3.2.1-1.fc26.x86_64 I can disable '3dnowprefetch' CPU feature in guest via 'xl' command, with adding `cpuid='host,3dnowprefetch=0'` into the CFG file. However, follow the instruction (https://libvirt.org/formatdomain.html#elementsCPU <https://libvirt.org/formatdomain.html#elementsCPU>), I added the following block into my XML file: ``` <cpu mode='host-passthrough' check='none'> <feature policy='disable' name='3dnowprefetch'/> </cpu> ``` Created the instance, seemed this feature was not being disabled in my guest. (I was able to see '3dnowprefetch' in `lscpu` outputs) Anybody has idea on this? Does libvirt support this for Xen?