Bug 1269697

Summary: The error message should be improved while specify the ioeventfd disk
Product: Red Hat Enterprise Linux 7 Reporter: Xuesong Zhang <xuzhang>
Component: libvirtAssignee: Libvirt Maintainers <libvirt-maint>
Status: CLOSED NOTABUG QA Contact: Virtualization Bugs <virt-bugs>
Severity: medium Docs Contact:
Priority: medium    
Version: 7.2CC: dyuan, jsuchane, mkletzan, mzhan, pzhang, rbalakri
Target Milestone: rc   
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
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Fixed In Version: Doc Type: Bug Fix
Doc Text:
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Clone Of: Environment:
Last Closed: 2015-11-26 13:18:25 UTC Type: Bug
Regression: --- Mount Type: ---
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Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description Xuesong Zhang 2015-10-08 01:56:22 UTC
Description of problem:
While enalbe the ioeventfd in both the <disk...> and <<controller type='scsi'...> xml section, and the disk is one scsi disk, the error message should be improved since ioeventfd is support for both virtio and scsi disk now, not only virtio disk.

Version-Release number of selected component (if applicable):
libvirt-1.2.17-10.el7.x86_64
qemu-kvm-rhev-2.3.0-22.el7.x86_64
kernel-3.10.0-319.el7.x86_64


How reproducible:
100%

Steps to Reproduce:
1. prepare one guest like following one, enalbe the ioeventfd in both the <disk...> and <<controller type='scsi'...> xml section, and the disk is one scsi disk.
......
    <disk type='file' device='disk'>
      <driver name='qemu' type='qcow2' ioeventfd='on'/>
      <source file='/var/lib/libvirt/images/rhel7.1-virtio.img'/>
      <backingStore/>
      <target dev='sda' bus='scsi'/>
    </disk>
   <controller type='scsi' index='0'>
      <driver ioeventfd='on'/>
    </controller>
......
2. but the dumpxml can not be saved, it seems the ioeventfs='on' only support for the virtio bus.
# virsh edit rhel71
error: unsupported configuration: disk ioeventfd mode supported only for virtio bus
Failed. Try again? [y,n,i,f,?]: 

Actual results:
as step 2.

Expected results:
The error message os step2 should improved, since the ioeventfd is support by both virtio and scsi disk now.

Additional info:

Comment 1 Martin Kletzander 2015-10-14 10:42:30 UTC
Reading the message ince again, I see that there is no problem with that.  LEt me explain.  The message says taht "disk ioeventfd" is onlyvalid for virtio.  And that's true, ioeventfd makes sense on virtio devices only, so scsi disk has no reason to have ioeventfd enabled.  And yes, you can have scsi disck attached to a controller that is virtio and has ioeventfd, but that doesn't amke the disk virtio, but the whole controller.

Comment 2 Jaroslav Suchanek 2015-11-26 13:18:25 UTC
Closing per comment 1.