Changes/Virt ARM on x86

ARM on x86 with libvirt/virt-manager

Summary

Fix running ARM VMs on x86 hosts using standard libvirt tools libvirt virsh, virt-manager and virt-install.

Owner

• Name: Cole Robinson
• Email: crobinso@redhat.com
• Release notes owner:

Current status

• Targeted release: Fedora 20
• Last updated: 2013-06-11
• Tracker bug: #998505

Detailed Description

qemu has an ARM emulator that works well and is actively used in the Fedora ARM effort. However libvirt and virt-manager currently have issues launching qemu-system-arm VMs, mostly by encoding x86 assumptions in the generated command line that cause qemu-system-arm to fail to start. Let's fix it!

Benefit to Fedora

• ARM developers can now use virt-manager/libvirt to manage ARM VMs without having to hack around it
• Fedora QA can use standard tools to test ARM in its bid for Primary Architecture
• Packagers who want to do ARM work can use standard virt tools to run ARM VMs.
• Enthusiasts who want to try out the Fedora ARM spin can use standard tools to try it in a VM.

Scope

• Proposal owners:

1. Fix issues in libvirt with generating qemu-system-arm command lines:
   • Fix launching vexpress-a9 (DONE)
   • Support virtio-mmio to enable virtio for vexpress (DONE)
   • TODO: vexpress-a15 support? need to figure out the correct qemu+fedora incantation
2. virt-install support (DONE, see docs)
3. virt-manager support
   • Basic setup support (DONE, see docs)
   • TODO: Improve the 'Create VM' wizard to handle the ARM case better
     • Move 'arch' selection to the first screen
     • Allow choosing machine type up front in first screen
     • UI for setting kernel/initrd in create wizard
4. Figure out how to actually install a new ARM VM and not depend on pre-installed images.
5. Figure out why graphical setup is busted

Upgrade/compatibility impact

N/A (not a System Wide Change)

How To Test

TBD when work is testable.

User Experience

N/A (not a System Wide Change)

Dependencies

N/A (not a System Wide Change)

Contingency Plan

• Contingency mechanism: N/A (not a System Wide Change)
• Contingency deadline: N/A (not a System Wide Change)
• Blocks release? N/A (not a System Wide Change)

Documentation

Follow the instructions here to get a pre-installed F19 ARM image, and extract the kernel/initrd/dtb: Architectures/ARM/F19/Installation#For_Versatile_Express_Emulation_with_QEMU

virt-install example:

sudo virt-install \
--name armvirtio --ram 1024 \
--arch armv7l --machine vexpress-a9 \
--boot kernel=/var/lib/libvirt/images/vmlinuz-3.9.5-301.fc19.armv7hl,initrd=/var/lib/libvirt/images/initramfs-3.9.5-301.fc19.armv7hl.img,dtb=/var/lib/libvirt/images/dtb-3.9.5-301.fc19.armv7hl,kernel_args="console=ttyAMA0 rw root=/dev/vda3" \
--disk /var/lib/libvirt/images/Fedora-XFCE-armhfp-19-1-sda.raw \
--nographics --os-variant fedora19

Using virtio requires a dtb to be passed in, but a dtb isn't strictly required otherwise.

Creating the VM with virt-manager is a bit more convoluted at the moment, the 'Scope' section details some improvements we can make before F20 GA. Steps:

• 'New VM' wizard
• 'Import existing disk image'
• Point at the above referenced ARM image. Choose Fedora 19 as the OS
• Fill in whatever for RAM and CPU
• On the final page, click customize before install
• Under advanced options, choose virt type 'qemu', arch 'armv7l'
• Click 'finish'
• In the 'customize' wizard, go to 'Overview', change machine type to 'vexpress-a9'
• Go to 'Boot settings', under 'direct kernel boot', specify kernel, initrd, dtb, and kernel args as specified above
• Remove the 'graphics' and 'video' device
• Click 'begin installation'

Release Notes

ARM VMs can now be run on x86 hosts using standard libvirt tools like virsh, virt-manager, and virt-install.