Public bug reported:

== Comment: #10 - VIPIN K. PARASHAR <[email protected]> - 2016-10-04 02:39:30 
==
(In reply to comment #9)
> I took a quick look to this one and also noticed these 2 links:
> https://bugzilla.redhat.com/show_bug.cgi?id=1237034
> http://marc.info/?l=linux-kernel&m=143737274332400&w=2
> and it looks like to avoid these message maybe just need to have this in
> config file:
> CONFIG_KVM_VFIO=y
> I think we have that in powerkvm but not in Ubuntu KVM.

On x86 running Ubuntu 16.04
==================
$ lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu 16.04.1 LTS
Release:        16.04
Codename:       xenial
$ head /proc/cpuinfo 
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 6
model           : 61
model name      : Intel(R) Core(TM) i5-5300U CPU @ 2.30GHz
stepping        : 4
microcode       : 0x22
cpu MHz         : 2300.179
cache size      : 3072 KB
physical id     : 0
$ uname -a
Linux Workstation 4.4.0-38-generic #57-Ubuntu SMP Tue Sep 6 15:42:33 UTC 2016 
x86_64 x86_64 x86_64 GNU/Linux
$ grep CONFIG_KVM_VFIO /boot/config-4.4.0-38-generic 
CONFIG_KVM_VFIO=y
$

On PowerPC
======== 
# lsb_release -a
No LSB modules are available.
Distributor ID: Ubuntu
Description:    Ubuntu Yakkety Yak (development branch)
Release:        16.10
Codename:       yakkety
# head /proc/cpuinfo
processor       : 0
cpu             : POWER8E (raw), altivec supported
clock           : 2061.000000MHz
revision        : 2.1 (pvr 004b 0201)

processor       : 1
cpu             : POWER8E (raw), altivec supported
clock           : 2061.000000MHz
revision        : 2.1 (pvr 004b 0201)

# uname -a
Linux c158f2u09os 4.8.0-17-generic #19 SMP Thu Sep 29 12:03:21 CDT 2016 ppc64le 
ppc64le ppc64le GNU/Linux
# grep CONFIG_KVM_VFIO /boot/config-4.8.0-17-generic 
#

I see that CONFIG_KVM_VFIO is enabled on x86 running Ubuntu 16.04
while ppc64 running 16.10 doesn't have it enabled.

== Comment: #9 - Carol L. Soto <[email protected]> - 2016-09-30 16:25:32 ==
I took a quick look to this one and also noticed these 2 links:
https://bugzilla.redhat.com/show_bug.cgi?id=1237034
http://marc.info/?l=linux-kernel&m=143737274332400&w=2
and it looks like to avoid these message maybe just need to have this in config 
file:
CONFIG_KVM_VFIO=y
I think we have that in powerkvm but not in Ubuntu KVM.

== Comment: #6 - VIPIN K. PARASHAR <[email protected]> - 2016-09-23 06:50:22 
==
$ git log 178a787502123b0 -1
commit 178a787502123b01499c5a4617b94bb69ad49dd5
Author: David Gibson <[email protected]>
Date:   Mon Feb 1 11:14:15 2016 +1100

    vfio: Enable VFIO device for powerpc
    
    ec53500f "kvm: Add VFIO device" added a special KVM pseudo-device which is
    used to handle any necessary interactions between KVM and VFIO.
    
    Currently that device is built on x86 and ARM, but not powerpc, although
    powerpc does support both KVM and VFIO.  This makes things awkward in
    userspace
    
    Currently qemu prints an alarming error message if you attempt to use VFIO
    and it can't initialize the KVM VFIO device.  We don't want to remove the
    warning, because lack of the KVM VFIO device could mean coherency problems
    on x86.  On powerpc, however, the error is harmless but looks disturbing,
    and a test based on host architecture in qemu would be ugly, and break if
    we do need the KVM VFIO device for something important in future.
    
    There's nothing preventing the KVM VFIO device from being built for
    powerpc, so this patch turns it on.  It won't actually do anything, since
    we don't define any of the arch_*() hooks, but it will make qemu happy and
    we can extend it in future if we need to.
    
    Signed-off-by: David Gibson <[email protected]>
    Reviewed-by: Eric Auger <[email protected]>
    Signed-off-by: Paul Mackerras <[email protected]>
$ 

$ git describe --contains 178a787502123b
v4.6-rc1~141^2~49^2~20
$ 


Commit (178a7875) seems to have enabled VFIO devices for powerpc.
But this commit should already be available since 4.6 kernel and ubuntu is
using 4.7 kernel here, so this should be already in.


== Comment: #0 - SRIKANTH B. AITHAL <[email protected]> - 2016-09-15 
12:31:49 ==
---Problem Description---
QEMU throwing false failure message while booting guest with SRIOV VF device

 
---uname output---
Linux c158f2u09os 4.7.0unofficial #5 SMP Mon Sep 5 08:53:38 EDT 2016 ppc64le 
ppc64le ppc64le GNU/Linux
 
---Additional Hardware Info---
Mellanox CX4 

 
Machine Type = 8247-22L 
 
---Debugger---
A debugger is not configured
 
---Steps to Reproduce---
 1. Edit guest ubuntu1610_srik and add below VF device [cold plug]
    <hostdev mode='subsystem' type='pci' managed='yes'>
      <source>
        <address domain='0x0005' bus='0x01' slot='0x00' function='0x3'/>
      </source>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' 
function='0x0'/>
    </hostdev>

2. Start the guest: virsh start ubuntu1610_srik

3. In the /var/log/libvirt/qemu/ubuntu1610_srik.log we will notice below
failure message.

"-device vfio-pci,host=0005:01:00.3,id=hostdev0,bus=pci.0,addr=0x1:
Failed to create KVM VFIO device: No such device"

But VF would have been passthroughed and probed succesfully inside the
guest.. I could configure it and transfer data over it.. and VF got
reprobed succesfully in host after I took down 'ubuntu1610_srik'.

This bug is to see why QEMU is printing false failure message.

=====================
Environment details:
=====================

Host : 
        Ubuntu 16.10
        kernel version: 
        Linux c158f2u09os 4.7.0unofficial #5 SMP Mon Sep 5 08:53:38 EDT 2016 
ppc64le ppc64le ppc64le GNU/Linux
Guest: 
1. ubuntu1610_srik
        kernel version: 4.7.0unofficial
2. ubuntu160401_srik
        kernel version: 4.4.0-38-generic

MOFED versions:
        MOFED version in Host as well Guest: 3.4-OFED.3.4.0.1.0.1
        CX4 Firmware version: 12.17.0222

** Affects: linux (Ubuntu)
     Importance: Undecided
     Assignee: Taco Screen team (taco-screen-team)
         Status: New


** Tags: architecture-ppc64le bugnameltc-146368 severity-medium 
targetmilestone-inin1610

** Tags added: architecture-ppc64le bugnameltc-146368 severity-medium
targetmilestone-inin1610

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https://bugs.launchpad.net/bugs/1630554

Title:
  QEMU throws failure msg while booting guest with SRIOV VF

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