In QEMU 1.6 parameters of 'drive' option were removed:
QemuOptsList qemu_drive_opts = {
.name = "drive",
.head = QTAILQ_HEAD_INITIALIZER(qemu_drive_opts.head),
.desc = {
/*
* no elements => accept any params
* validation will happen later
*/
{ /* end of list */ }
},
};
But libvirt still checks for QEMU_CAPS_DRIVE_DISCARD using QMP
query-command-line-options:
static struct virQEMUCapsCommandLineProps virQEMUCapsCommandLine[] = {
{ "machine", "mem-merge", QEMU_CAPS_MEM_MERGE },
{ "drive", "discard", QEMU_CAPS_DRIVE_DISCARD },
{ "realtime", "mlock", QEMU_CAPS_MLOCK },
};
...
qemuMonitorGetCommandLineOptionParameters(mon,
virQEMUCapsCommandLine[i].option, &values)
So, when I try to use discard option in domain xml I get this error:
error : qemuBuildDriveStr:3986 : unsupported configuration: discard is not
supported by this QEMU binary