Bug 1348422

Summary:	error flow from monitor when moving mouse with virtio input device
Product:	Red Hat Enterprise Linux 7	Reporter:	mazhang <mazhang>
Component:	qemu-kvm-rhev	Assignee:	Gerd Hoffmann <kraxel>
Status:	CLOSED DUPLICATE	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	low	Docs Contact:
Priority:	low
Version:	7.3	CC:	knoel, kraxel, mazhang, michen, qzhang, virt-maint
Target Milestone:	rc
Target Release:	---
Hardware:	ppc64le
OS:	Unspecified
Whiteboard:
Fixed In Version:	qemu 2.7	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2016-08-12 11:41:04 UTC	Type:	Bug
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description mazhang 2016-06-21 07:06:56 UTC

Description of problem:
error flow from monitor when moving mouse with virtio input device

Version-Release number of selected component (if applicable):

Host:
3.10.0-447.el7.ppc64le
qemu-kvm-rhev-2.6.0-7.el7.ppc64le

Guest:
3.10.0-433.el7.ppc64le

How reproducible:
always

Steps to Reproduce:
1.Start vm with virtio input device:
/usr/libexec/qemu-kvm \
-name 'virt-tests-vm1'  \
-sandbox off  \
-machine pseries  \
-nodefaults  \
-vga std  \
-serial unix:/tmp/socket-mazhang,server,nowait \
-qmp tcp:0:6666,server,nowait \
-device virtio-net-pci,mac=9a:c3:c4:c5:c6:c7,id=idmk198l,vectors=4,netdev=id0KwqaV,bus=pci.0,addr=05,disable-legacy=off,disable-modern=on  \
-netdev tap,id=id0KwqaV,vhost=on  \
-m 8192  \
-smp 8,maxcpus=8,cores=4,threads=1,sockets=2 \
-device virtio-scsi-pci,id=virtio_scsi_pci0,bus=pci.0,addr=06,disable-legacy=off,disable-modern=on \
-drive id=drive_disk1,if=none,snapshot=off,aio=threads,file=/root/test_home/mazhang/images/RHEL-Server-7.3-ppc64le-virtio-scsi.qcow2 \
-device scsi-hd,id=disk1,drive=drive_disk1,bootindex=0 \
-vnc :11  \
-rtc base=utc,clock=host  \
-boot menu=on  \
-enable-kvm \
-monitor stdio \
-device virtio-mouse-pci,id=mouse0 \
-device virtio-keyboard-pci,id=kbd0 \


2. Login guest, keep moving mouse.

3.

Actual results:
hmp print error messages:

(qemu) virtio_input_send: ENOSPC in vq, dropping events
virtio_input_send: ENOSPC in vq, dropping events
virtio_input_send: ENOSPC in vq, dropping events
virtio_input_send: ENOSPC in vq, dropping events
virtio_input_send: ENOSPC in vq, dropping events
virtio_input_send: ENOSPC in vq, dropping events
virtio_input_send: ENOSPC in vq, dropping events
virtio_input_send: ENOSPC in vq, dropping events
virtio_input_send: ENOSPC in vq, dropping events
virtio_input_send: ENOSPC in vq, dropping events
virtio_input_send: ENOSPC in vq, dropping events


Expected results:
No errors.

Additional info:
qemu-kvm-rhev-2.6.0-7.el7.x86_64 doesn't hit this problem.

Comment 2 Gerd Hoffmann 2016-06-21 12:51:06 UTC

Graphical login or text console?
Does the mouse work?

Comment 3 mazhang 2016-06-22 02:53:01 UTC

(In reply to Gerd Hoffmann from comment #2)
> Graphical login or text console?
> Does the mouse work?

Graphical login, and the mouse was working.

Comment 4 Gerd Hoffmann 2016-06-22 08:59:34 UTC

(In reply to mazhang from comment #3)
> (In reply to Gerd Hoffmann from comment #2)
> > Graphical login or text console?
> > Does the mouse work?
> 
> Graphical login, and the mouse was working.

When do those messages show up?  Any chance this happens only before the guest driver is loaded and active?

If the mouse is working fine this seems to be a cosmetic issue only.  The
message should probably converted to a tracepoint.  It's not helpful, except
for trouble-shooting.

Comment 5 mazhang 2016-06-22 10:12:29 UTC

(In reply to Gerd Hoffmann from comment #4)
> (In reply to mazhang from comment #3)
> > (In reply to Gerd Hoffmann from comment #2)
> > > Graphical login or text console?
> > > Does the mouse work?
> > 
> > Graphical login, and the mouse was working.
> 
> When do those messages show up?  Any chance this happens only before the
> guest driver is loaded and active?

Those messages shows up after virtio_input module loaded.

> 
> If the mouse is working fine this seems to be a cosmetic issue only.  The
> message should probably converted to a tracepoint.  It's not helpful, except
> for trouble-shooting.

Comment 6 Gerd Hoffmann 2016-08-12 08:04:01 UTC

Fixed in qemu 2.7:

commit c80276b4206d534daaaf87305df5805db1b8db02
Author: Gerd Hoffmann <kraxel>
Date:   Thu Jun 23 11:51:35 2016 +0200

    input: add trace events for full queues
    
    It isn't unusual to happen, for example during reboot when the guest
    doesn't reveice events for a while.  So better don't flood stderr
    with alarming messages.  Turn them into tracepoints instead so they
    can be enabled in case they are needed for trouble-shooting.
    
    Signed-off-by: Gerd Hoffmann <kraxel>
    Message-id: 1466675495-28797-1-git-send-email-kraxel

... lets pick it up with the next rebase.

Comment 7 Gerd Hoffmann 2016-08-12 11:41:04 UTC

thuth did the backport already for another bug ...

*** This bug has been marked as a duplicate of bug 1366471 ***