Red Hat Bugzilla – Bug 1475424
Nested virtualization problem in kvm_amd with host-passthrough
Last modified: 2017-07-26 12:08:18 EDT
Description of problem: Nested virtualization with kvm_amd does not work in Fedora 26. svm flag is not available in virtual machine while using host-passthrough mode for CPU
Version-Release number of selected component (if applicable): Kernels 4.11.8-300.fc26.x86_64 through 4.11.10-300.fc26.x86_64
Steps to Reproduce: (In AMD FX-8320 system)
1. Install virtualization package group and restart (or start libvirtd).
2. Observe svm flag in /proc/cpuinfo and confirm /sys/modules/kvm_amd/parameters/nested to have 1 (even without enabling in /etc/modprobe.d/kvm.conf .
3. Create virtual machine with host-passthrough for CPU
3. Observe missing svm flag in /proc/cpuinfo in virtual machine.
Nested virtualization not working; only emulation available in virtual machine
(As functional in Fedora 25), nested virtualization works
Fresh install of Fedora 25 on the same machine shows nested virtualization working fine. Fedora 26 x86_64 on Intel Core i5 based machine has functional nested virtualization.