> > Hi Paolo, > > I've noticed that KVM is not actually enabled on my machines. /dev/kvm > is missing. If I mknod it manually, opens return ENODEV. > After several hours of debugging I figured that it seems to be caused by: > > commit 91fa0f8e9e2937fd9360f326ad60d51908347afd > Author: Paolo Bonzini <pbonz...@redhat.com> > Date: Wed Jun 15 20:55:08 2016 +0200 > KVM: x86: always use "acknowledge interrupt on exit" > > If I move VM_EXIT_ACK_INTR_ON_EXIT from min back to opt. /dev/kvm > become functional again (at least I can open it). > > To make it clear, it all happens inside of qemu instance. I've tried > using different cpus in qemu, including "host" cpu which is pretty > capable: > > model name : Intel(R) Xeon(R) CPU E5-2690 v3 @ 2.60GHz > flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov > pat pse36 clflush mmx fxsr sse sse2 ss syscall nx pdpe1gb rdtscp lm > constant_tsc arch_perfmon rep_good nopl eagerfpu pni pclmulqdq vmx > ssse3 fma cx16 pcid sse4_1 sse4_2 x2apic movbe popcnt > tsc_deadline_timer aes xsave avx f16c rdrand hypervisor lahf_lm abm > vnmi ept fsgsbase tsc_adjust bmi1 avx2 smep bmi2 erms invpcid xsaveopt > > So why am I missing VM_EXIT_ACK_INTR_ON_EXIT feature? How does it work > for other users? And how should I fix it in a proper way?
You need to upgrade your host kernel to 3.16 (or possibly 3.17, but I think it's 3.16). This is a virtualization feature, and it is not provided by the processor (as is the case for "-cpu host" features); it's provided by the host kernel. Thanks, Paolo