Ah.. You got that error when starting a VM ? No worries, there are certain scenarios which can bring this error from libvirt. I would recommend you to go through below check list:
1) Something wrong with the kvm modules. That said, please check below possibility first:
kvm and kvm_intel ( for intel systems or systems with 'vmx' flag) / kvm_amd ( AMD systems or systems with 'svm' flag) are loaded correctly in the system.
If it is not, load those .. Not able to load those modules ? then check "dmesg" for something like "KVM is disabled by bios" string.
2) Once this is done or its already loaded, then verify whether 'hvm' capability is listed in 'host' and 'guest' section of via 'virsh capabilities' ( grep for 'hvm' string) command
os_type hvm os_type
If it is listed and still no luck
3) Try to restart 'libvirtd' service and find the result ..
Still no luck ? ?
4) Now check whether all required packages (ex:'qemu') are installed, if it is not, install it and check..
5) If still failed, check whether its an issue with all the vms ? or only one ? if its all the VMs , then check the 'emulator' definition of guest xml for the 'qemu-kvm' binary path.. Any modification to that path or does the binary exist in that path ?
hmmmmm, u r still unlucky ?
Please let me know via comment 🙂