Bug 1026184

Libvirt is relying on the query-command-line-options for deciding whether to support drive discard options.

Is the patch in qemu.git master now? except the drive discard, there are other 3 capability flags depended on query-command-line-options. So we would like see the patch could be backported as soon as possible.

Fix included in qemu-kvm-1.5.3-51.el7

Reproduce this bug as follow version:
Host:
# uname -r
3.10.0-99.el7.x86_64
# rpm -q qemu-kvm-rhev
qemu-kvm-rhev-1.5.3-50.el7.x86_64
# rpm -q seabios
seabios-1.7.2.2-11.el7.x86_64

Guest:
3.10.0-99.el7.x86_64

Steps:
1.Boot guest with 
 /usr/libexec/qemu-kvm -M pc-i440fx-rhel7.0.0 -cpu SandyBridge -enable-k048 -smp 4,sockets=2,cores=2,threads=1 -no-kvm-pit-reinjection -usb -device usb-tablet,id=input0 -name RHEL7.0 -uuid `uuidgen` -rtc base=localtime,clock=host,driftfix=slew -device ahci,id=ahci0 -drive if=none,file=/home/rhel7base.qcow2_v3,format=qcow2,id=drive-sata0-0-0 -device ide-drive,bus=ahci0.0,drive=drive-sata0-0-0,id=sata0-0-0  -netdev tap,id=hostdev0,vhost=on,script=/etc/qemu-ifup,queues=4 -device virtio-net-pci,netdev=hostdev0,vectors=10,mq=on,mac=14:32:19:82:9b:12,id=vnet0 -device virtio-balloon-pci,bus=pci.0,id=balloon0 -monitor stdio  -vnc :10 -vga qxl -qmp tcp:0:5555,server,nowait


2.# telnet 10.66.5.251 5555
Trying 10.66.5.251...
Connected to 10.66.5.251.
Escape character is '^]'.
{"QMP": {"version": {"qemu": {"micro": 3, "minor": 5, "major": 1}, "package": " (qemu-kvm-1.5.3-50.el7)"}, "capabilities": []}}
{"execute":"qmp_capabilities"}
{"return": {}}
{ 'execute': 'query-command-line-options', 'arguments': { 'option': 'drive' } }

Results:returns a NULL parameter
{"return": [{"parameters": [], "option": "drive"}]}

Verify this bug as follow version:
Host:

Version:
Host:
# uname -r 
3.10.0-99.el7.x86_64
[root@localhost qemu52]# rpm -q qemu-kvm
qemu-kvm-1.5.3-52.el7.x86_64

Guest:
3.10.0-99.el7.x86_64

Steps as same as reproduce 

Results:
{"return": [{"parameters": [{"name": "copy-on-read", "help": "copy read data from backing file into image file", "type": "boolean"}, {"name": "read-only", "help": "open drive file as read-only", "type": "boolean"}, {"name": "addr", "help": "pci address (virtio only)", "type": "string"}, {"name": "boot", "help": "(deprecated, ignored)", "type": "boolean"}, {"name": "trans", "help": "chs translation (auto, lba, none)", "type": "string"}, {"name": "secs", "help": "number of sectors (ide disk geometry)", "type": "number"}, {"name": "heads", "help": "number of heads (ide disk geometry)", "type": "number"}, {"name": "cyls", "help": "number of cylinders (ide disk geometry)", "type": "number"}, {"name": "if", "help": "interface (ide, scsi, sd, mtd, floppy, pflash, virtio)", "type": "string"}, {"name": "media", "help": "media type (disk, cdrom)", "type": "string"}, {"name": "index", "help": "index number", "type": "number"}, {"name": "unit", "help": "unit number (i.e. lun for scsi)", "type": "number"}, {"name": "bus", "help": "bus number", "type": "number"}, {"name": "throttling.bps-write", "help": "limit write bytes per second", "type": "number"}, {"name": "throttling.bps-read", "help": "limit read bytes per second", "type": "number"}, {"name": "throttling.bps-total", "help": "limit total bytes per second", "type": "number"}, {"name": "throttling.iops-write", "help": "limit write operations per second", "type": "number"}, {"name": "throttling.iops-read", "help": "limit read operations per second", "type": "number"}, {"name": "throttling.iops-total", "help": "limit total I/O operations per second", "type": "number"}, {"name": "werror", "help": "write error action", "type": "string"}, {"name": "rerror", "help": "read error action", "type": "string"}, {"name": "serial", "help": "disk serial number", "type": "string"}, {"name": "format", "help": "disk format (raw, qcow2, ...)", "type": "string"}, {"name": "aio", "help": "host AIO implementation (threads, native)", "type": "string"}, {"name": "cache.no-flush", "help": "ignore any flush requests for the device", "type": "boolean"}, {"name": "cache.direct", "help": "enables use of O_DIRECT (bypass the host page cache)", "type": "boolean"}, {"name": "cache.writeback", "help": "enables writeback mode for any caches", "type": "boolean"}, {"name": "discard", "help": "discard operation (ignore/off, unmap/on)", "type": "string"}, {"name": "file", "help": "disk image", "type": "string"}, {"name": "snapshot", "help": "enable/disable snapshot mode", "type": "boolean"}], "option": "drive"}]}


According to above test ,this bug fixed.

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.