Bug 890024 - Guest should failed to be booted if specifying iops,bps as negative value
Guest should failed to be booted if specifying iops,bps as negative value
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: qemu-kvm (Show other bugs)
Unspecified Unspecified
low Severity low
: rc
: ---
Assigned To: Stefan Hajnoczi
Virtualization Bugs
: FutureFeature
Depends On:
Blocks: 987725
  Show dependency treegraph
Reported: 2012-12-24 07:00 EST by juzhang
Modified: 2014-06-17 23:19 EDT (History)
8 users (show)

See Also:
Fixed In Version: 1.5
Doc Type: Enhancement
Doc Text:
Story Points: ---
Clone Of:
: 987725 (view as bug list)
Last Closed: 2014-06-13 07:46:13 EDT
Type: Bug
Regression: ---
Mount Type: ---
Documentation: ---
Verified Versions:
Category: ---
oVirt Team: ---
RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: ---

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Description juzhang 2012-12-24 07:00:58 EST
Description of problem:
Guest should be failed to boot if specifying iops,bps as negative value.

Version-Release number of selected component (if applicable):
Host Kernel
#uname -r
qemu-kvm version

How reproducible:

Steps to Reproduce:
1.Boot guest with specifying bps=-1024000,iops=-100
#-drive file=/root/zhangjunyi/hotadd_15G.qcow2,if=none,id=drive-scsi-disk_test,format=qcow2,cache=none,werror=stop,rerror=stop,bps=-1024000,iops=-100 -device scsi-disk,drive=drive-scsi-disk_test,bus=scsi0.0,scsi-id=0,lun=1,id=scsi-disk_test
Actual results:
Guest can booted without promoting any messages.
(qemu)info block
drive-scsi-disk_test: removable=0 io-status=ok file=/root/zhangjunyi/hotadd_15G.qcow2 ro=0 drv=qcow2 encrypted=0 bps=-1024000 bps_rd=0 bps_wr=0 iops=-100 iops_rd=0 iops_wr=0

Expected results:
Guest should failed to be booted and promote friendly message like
"Parameter 'iops' expects a positive number"

Additional info:
1. I tried latest upstream(qemu1.3), hit the same issue.
2. I checked the code #vi block_int.h
typedef struct BlockIOLimit {
    int64_t bps[3];
    int64_t iops[3];
} BlockIOLimit;

Why do not set uint64_t bps[3] instead of int64_t bps[3]?
3. File bug first, will check more io throttling codes.
Comment 1 juzhang 2012-12-25 04:32:13 EST
Additional info:
Can we add a similar function for checking iops/iops_wr/iops_rd/bsp_wr/bps_rd/bps value  like bool do_check_io_limits?
snip code of source
#vi blockdev.c
static bool do_check_io_limits(BlockIOLimit *io_limits)
    bool bps_flag;
    bool iops_flag;


    bps_flag  = (io_limits->bps[BLOCK_IO_LIMIT_TOTAL] != 0)
                 && ((io_limits->bps[BLOCK_IO_LIMIT_READ] != 0)
                 || (io_limits->bps[BLOCK_IO_LIMIT_WRITE] != 0));
    iops_flag = (io_limits->iops[BLOCK_IO_LIMIT_TOTAL] != 0)
                 && ((io_limits->iops[BLOCK_IO_LIMIT_READ] != 0)
                 || (io_limits->iops[BLOCK_IO_LIMIT_WRITE] != 0));
    if (bps_flag || iops_flag) {
        return false;

    return true;

if (!do_check_io_limits(&io_limits)) {
        error_report("bps(iops) and bps_rd/bps_wr(iops_rd/iops_wr) "
                     "cannot be used at the same time");
        return NULL;
Comment 2 Stefan Hajnoczi 2013-02-13 11:12:28 EST
Thanks for reporting this bug and your suggestions.

I have posted a patch series upstream:

Once it has been merged I will backport for RHEL 7, if necessary.
Comment 3 Stefan Hajnoczi 2013-03-13 10:41:30 EDT
Fixed upstream, will be available in QEMU 1.5.

commit 7d81c1413c9c9bdcc966453636e4ca7776b59861
Author: Stefan Hajnoczi <stefanha@redhat.com>
Date:   Wed Feb 13 16:53:43 2013 +0100

    block: refuse negative iops and bps values
Comment 4 Sibiao Luo 2013-05-23 21:59:00 EDT
Reproduce this issue on qemu-kvm-1.4.0-4.el7, it can boot guest with specifying iops,bps as negative value.
host info:

e.g:...-drive file=/mnt/my-data-disk.qcow2,if=none,id=drive-data-disk,format=qcow2,readonly=on,cache=none,aio=native,werror=stop,rerror=stop,bps=-102400000,iops=-100000 -device virtio-blk-pci,bus=pcie.0,addr=0x7,drive=drive-data-disk,id=data-disk

it can boot guest with specifying iops,bps as negative value.
(qemu) info block
drive-system-disk: removable=0 io-status=ok file=/mnt/RHEL-7.0-20130403.0_x86_64.qcow3bk ro=0 drv=qcow2 encrypted=0 bps=0 bps_rd=0 bps_wr=0 iops=0 iops_rd=0 iops_wr=0
drive-data-disk: removable=0 io-status=ok file=/mnt/my-data-disk.qcow2 ro=1 drv=qcow2 encrypted=0 bps=-102400000 bps_rd=0 bps_wr=0 iops=-100000 iops_rd=0 iops_wr=0

Verify this issue on qemu-kvm-1.5.0-1.el7.x86_64.
hot info:
guest info:
It fail to boot guest with specifying iops,bps as negative value, and qemu give a friendly reminds.
qemu-kvm: -drive file=/mnt/my-data-disk.qcow2,if=none,id=drive-data-disk,format=qcow2,readonly=on,cache=none,aio=native,werror=stop,rerror=stop,bps=-102400000,iops=-100000: bps and iops values must be 0 or greater

Base on above, this issue has been fixed successfully.
Comment 7 Ludek Smid 2014-06-13 07:46:13 EDT
This request was resolved in Red Hat Enterprise Linux 7.0.

Contact your manager or support representative in case you have further questions about the request.

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