Screenshot trying to boot a mini-iso from http://archive.ubuntu.com/ubuntu/dists/${release}/main/installer-${arch}/current/iamges/netboot/mini.iso, with both trusty and precise amd64, using command line:
kvm -enable-kvm -drive file=x.img,if=virtio.cache=none -cdrom precise- mini-amd64.iso -boot d -vnc :1 Running the command inside a 12.04.4 guest on a precise host with trusty kernel. ** Summary changed: - nested kvm on saucy kernel hangs + nested kvm fails with trust and upstream kernels ** Description changed: - I have a precise host with saucy ubuntu kernel installed. I installed - two VMs there, a saucy and a trusty guest. + First: the 3.2 precise kernel handled nested qemu very well. As of + saucy it has declined. + + In a host with saucy kernel (even on precise userspace), attempts to do + nested kvm result in a hung kvm (inside the guest - host proceeds ok) + taking 100%cpu. + + In a host with trusty kernel (even on precise userspace), nested kvm + fails get past grub. I have two screenshots, one resulting from + attempting to boot from a precise mini-iso, another from attempting to + boot a cloud image at: http://cloud-images.ubuntu.com/quantal/current + /quantal-server-cloudimg-amd64-disk1.img. (If you convert that image to + raw, it fails the same way). + + On the host, I see the following in /var/log/kern.log: kvm: zapping + shadow pages for mmio generation wraparound + + I've reproduced this both on (a) a intel based vostro laptop - with + separate installs of precise and saucy (with ubuntu precise, saucy, + trust, upstream kernels), (b) an intel based server with precise + userspace and saucy and trusty kernels; and (c) an intel laptop running + full uptodate trusty. + + As nested qemu worked will in the previous LTS, I think it is important + to have it working in 14.04 LTS. + + ============= Original description ================ + I have a precise host with saucy ubuntu kernel installed. I installed two VMs there, a saucy and a trusty guest. In the saucy guest, non-accelerated qemu works fine, but accelerated kvm hangs the first-level saucy guest completely, and pins it at 200% cpu usage: qemu-system-x86 --enable-kvm -monitor stdio -vnc :1 On the trusty guest it works just fine. ** Attachment added: "screenshot1.png" https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1278531/+attachment/3994631/+files/screenshot1.png -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1278531 Title: nested kvm fails with trust and upstream kernels To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1278531/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
