https://stackoverflow.com/questions/37300811/android-studio-dev-kvm-device-permission-denied
To check the ownership of /dev/kvm use
ls -al /dev/kvm
The user was root, the group kvm. To check which users are in the kvmgroup, use
grep kvm /etc/group
This returned
kvm:x:some_number:
on my system: as there is nothing left to the final :, there are no users in the kvm group.
To add the user username to the kvm group, you could use
sudo adduser username kvm
which adds the user to the group, and check once again with grep kvm /etc/group.
来源：https://www.cnblogs.com/or2-/p/9250925.html