Bug 1414641

Summary:	The HMP command "block_set_io_throttle" not support in qemu-kvm-rhev-2.8.0-2.el7
Product:	Red Hat Enterprise Linux 7	Reporter:	Yongxue Hong <yhong>
Component:	qemu-kvm-rhev	Assignee:	Eric Blake <eblake>
Status:	CLOSED WONTFIX	QA Contact:	Virtualization Bugs <virt-bugs>
Severity:	low	Docs Contact:
Priority:	low
Version:	7.4	CC:	chayang, coli, eblake, hhuang, juzhang, michen, ngu, qzhang, virt-maint, xuhan, xuma
Target Milestone:	rc
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2017-01-20 22:57:20 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 Yongxue Hong 2017-01-19 06:09:31 UTC

Description of problem:
The HMP command "block_set_io_throttle" not support in qemu-kvm-rhev-2.8.0-2.el7,but supported in qemu-kvm-rhev-2.6.0-28.el7_3.2

Version-Release number of selected component (if applicable):
Host kernel: 3.10.0-543.el7.ppc64le
qemu: qemu-kvm-rhev-2.8.0-2.el7

Guest kernel:3.10.0-543.el7.ppc64
How reproducible:
100%

Steps to Reproduce:
1.create two disk 
eg:
/usr/libexec/qemu-kvm \
-name RHEL7-8393 \
-M pseries-rhel7.4.0 \
-m 64G \
-smp 4 \
-boot menu=on,order=c \
-device virtio-scsi-pci,id=virtio_scsi_pci0,bus=pci.0,addr=06 \
-drive file=/home/hyx/os/RHEL-7.3-20161019.0-Server-ppc64-dvd1.iso,if=none,media=cdrom,id=image0 \
-device scsi-cd,id=scsi-cd0,drive=image0,channel=0,scsi-id=0,lun=0,bootindex=1 \
-drive file=/home/hyx/image/RHEL7-8393-2-18G.raw,if=none,media=disk,format=raw,cache=none,bps=102400,bps_rd=204800,id=image2 \
-device scsi-hd,id=scsi-hd2,drive=image2,channel=0,scsi-id=0,lun=1 \
-drive file=/home/hyx/image/RHEL7-8393-20G.raw,if=none,media=disk,format=raw,id=image1 \
-device scsi-hd,id=scsi-hd1,drive=image1,channel=0,scsi-id=0,lun=2,bootindex=0 \
-device nec-usb-xhci,id=xhci \
-drive file=/home/hyx/image/ubs-1G.raw,if=none,id=stick,bps_rd=102400,iops_rd=100,bps_wr=102400,iops_wr=100 \
-device usb-storage,removable=on,bus=xhci.0,drive=stick \
-netdev tap,id=hostnet0,script=/etc/qemu-ifup \
-device spapr-vlan,netdev=hostnet0,id=virtio-net-pci0,mac=70:e2:84:14:0e:18 \
-rtc base=utc,clock=vm \
-monitor stdio \
-serial unix:./sock1,server,nowait \
-qmp tcp:0:6000,server,nowait \
-device usb-tablet \
-vnc :1
2.boot guest and execute HMP command
eg:
(qemu) block_set_io_throttle scsi-hd2 102400 204800 0 0 0 0
or
(qemu) block_set_io_throttle image2 102400 204800 0 0 0 0

Actual results:
The HMP show "Need exactly one of 'device' and 'id'"

Expected results:
The command HMP could be executed successfully.

Additional info:

Comment 2 Ademar Reis 2017-01-20 14:42:44 UTC

I believe this was done on purpose:

commit 4dc9397b62c1a50a4afb5881abb55d07058e0812
Author: Eric Blake <eblake>
Date:   Wed Jul 13 21:50:21 2016 -0600

    block: Simplify block_set_io_throttle
    
    Now that we can support boxed commands, use it to greatly
    reduce the number of parameters (and likelihood of getting
    out of sync) when adjusting throttle parameters.
    
    Signed-off-by: Eric Blake <eblake>
    Reviewed-by: Alberto Garcia <berto>
    Message-Id: <1468468228-27827-11-git-send-email-eblake>
    Reviewed-by: Markus Armbruster <armbru>
    Signed-off-by: Markus Armbruster <armbru>

Anyway, given we don't support HMP in RHEL, it should be OK to close this BZ, but I'll let Eric review it once more.

Comment 3 Eric Blake 2017-01-20 22:57:20 UTC

Accidentally broken here:

commit 7a9877a0263561f11bae116a7639eec53a625807
Author: Kevin Wolf <kwolf>
Date:   Tue Sep 20 13:38:48 2016 +0200

    block: Accept device model name for block_set_io_throttle
    
    In order to remove the need for BlockBackend names in the external API,
    we want to allow qdev device names in all device related commands.
    
    This converts block_set_io_throttle to accept a qdev device name.
    
    Signed-off-by: Kevin Wolf <kwolf>

Agree that this does not affect RHEL, so there's nothing to backport, but I'll send the upstream patch to fix it, anyways.

Comment 4 Eric Blake 2017-01-20 23:15:31 UTC

Upstream patch
https://lists.gnu.org/archive/html/qemu-devel/2017-01/msg04473.html

Comment 5 Gu Nini 2017-03-02 09:38:12 UTC

Hi Eric,

I fail to understand what commit 4dc9397 intends doing. Since I am doing the io throttling test plan of RHEL7.4, could you give some explanation about the commit, should we add some related cases?

Thanks!
Nini Gu

Comment 6 Eric Blake 2017-03-02 14:10:02 UTC

(In reply to Gu Nini from comment #5)
> Hi Eric,
> 
> I fail to understand what commit 4dc9397 intends doing.

Commit 4dc9397 was an internal-only change (no semantic change to the user interface), designed to make parameter passing less of a maintenance burden by bundling multiple parameters into a struct.  The bug in question was introduced in commit 7a9877a, but even that affected only HMP, which is not supported in RHEL.

>  Since I am doing the
> io throttling test plan of RHEL7.4, could you give some explanation about
> the commit, should we add some related cases?
> 

As far as I can tell, there are no changes required to RHEL testing based on this bug.