armhf: virtio_mmio support

Bug #1235277 reported by Paolo Pisati on 2013-10-04
8
This bug affects 1 person
Affects Status Importance Assigned to Milestone
linux (Ubuntu)
Undecided
Paolo Pisati
Saucy
Undecided
Paolo Pisati

Bug Description

SRU Justification:

Impact: qemu 1.6 adds support for virtio memory mapped devices (like net and block) on arm. While S will probably ship with qemu 1.5, we know it'll be provided in a ppa and we want to take advantage of the speedup offered by virtio, so

1) turn on virtio_mmio on armhf (generic and generic-lpae)
2) uniform VIRTIO* support among all the different archs, making it a compiled-in options like on i386 and amd64

Fix: apply the attached config patch and recompile a kernel with it

Testcase: try booting a qemu kvm using a kernel without this patch:

sudo qemu-system-arm -machine vexpress-a15 -cpu cortex-a15 -enable-kvm -m 512M -kernel /boot/vmlinuz-`uname -r` -append "console=ttyAMA0 earlyprintk=serial root=/dev/mmcblk0 ro rootfstype=ext4" -serial stdio -dtb /lib/firmware/`uname -r`/device-tree/vexpress-v2p-ca15-tc1.dtb -initrd /boot/initrd.img-`uname -r` -drive if=sd,cache=writeback,file=saucy-server-cloudimg-armhf.img -net nic -net user,hostfwd=tcp::2223-:22 -display none

and then try to boot another instance using a kernel with the config patch applied:

sudo qemu-system-arm -machine vexpress-a15 -cpu cortex-a15 -enable-kvm -m 512M -kernel /boot/vmlinuz-`uname -r` -append "console=ttyAMA0 earlyprintk=serial root=/dev/vda ro rootfstype=ext4" -serial stdio -dtb /lib/firmware/`uname -r`/device-tree/vexpress-v2p-ca15-tc1.dtb -initrd /boot/initrd.img-`uname -r` -drive if=none,cache=writeback,file=saucy-server-cloudimg-armhf.img,id=foo -device virtio-blk-device,drive=foo -display none -netdev tap,id=tap0 -device virtio-net-device,netdev=tap0

the difference is noticeable to the naked eye.

This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:

apport-collect 1235277

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

Changed in linux (Ubuntu):
status: New → Incomplete
Tim Gardner (timg-tpi) on 2013-10-04
Changed in linux (Ubuntu Saucy):
assignee: nobody → Paolo Pisati (p-pisati)
status: Incomplete → In Progress
tags: added: patch

This bug was nominated against a series that is no longer supported, ie saucy. The bug task representing the saucy nomination is being closed as Won't Fix.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

Changed in linux (Ubuntu Saucy):
status: In Progress → Won't Fix
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