[libvirt] [PATCH 12/25] qemu: Add hotplug support for scsi host device

[John Ferlan]

On 05/13/2013 11:48 AM, Osier Yang wrote:
> On 07/05/13 20:42, John Ferlan wrote:
>> On 05/03/2013 02:07 PM, Osier Yang wrote:
>>> From: Han Cheng <hanc.fnst at cn.fujitsu.com>
>>>
>>> This adds both attachment and detachment support for scsi host
>>> device.
>>>
>>> Signed-off-by: Han Cheng <hanc.fnst at cn.fujitsu.com>
>>> Signed-off-by: Osier Yang <jyang at redhat>
>>> ---
>>>   src/qemu/qemu_hotplug.c | 141
>>> ++++++++++++++++++++++++++++++++++++++++++++++--
>>>   1 file changed, 136 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/src/qemu/qemu_hotplug.c b/src/qemu/qemu_hotplug.c
>>> index 422d336..e6bc3a2 100644
>>> --- a/src/qemu/qemu_hotplug.c
>>> +++ b/src/qemu/qemu_hotplug.c
>>> @@ -1194,6 +1194,74 @@ cleanup:
>>>       return ret;
>>>   }
>>>   +static int
>>> +qemuDomainAttachHostScsiDevice(virQEMUDriverPtr driver,
>>> +                               virDomainObjPtr vm,
>>> +                               virDomainHostdevDefPtr hostdev)
>>> +{
>>> +    int ret = -1;
>>> +    qemuDomainObjPrivatePtr priv = vm->privateData;
>>> +    char *devstr = NULL;
>>> +    char *drvstr = NULL;
>>> +
>>> +    if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DRIVE) ||
>>> +        !virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE) ||
>>> +        !virQEMUCapsGet(priv->qemuCaps,
>>> QEMU_CAPS_DEVICE_SCSI_GENERIC)) {
>>> +        virReportError(VIR_ERR_CONFIG_UNSUPPORTED, "%s",
>>> +                       _("SCSI passthrough is not supported by this
>>> version of qemu"));
>>> +        return -1;
>>> +    }
>>> +
>>> +    if (qemuPrepareHostdevSCSIDevices(driver, vm->def->name,
>>> +                                      &hostdev, 1)) {
>>> +        virReportError(VIR_ERR_INTERNAL_ERROR,
>>> +                       _("Unable to prepare scsi hostdev:
>>> %s:%d:%d:%d"),
>>> +                       hostdev->source.subsys.u.scsi.adapter,
>>> +                       hostdev->source.subsys.u.scsi.bus,
>>> +                       hostdev->source.subsys.u.scsi.target,
>>> +                       hostdev->source.subsys.u.scsi.unit);
>>> +        return -1;
>>> +    }
>>> +
>>> +    if (qemuAssignDeviceHostdevAlias(vm->def, hostdev, 0) < 0)
>>> +        goto cleanup;
>>> +
>>> +    if (!(drvstr = qemuBuildSCSIHostdevDrvStr(hostdev,
>>> priv->qemuCaps)))
>>> +        goto cleanup;
>>> +
>>> +    if (!(devstr = qemuBuildSCSIHostdevDevStr(vm->def, hostdev,
>>> priv->qemuCaps)))
>>> +        goto cleanup;
>>> +
>>> +    if (VIR_REALLOC_N(vm->def->hostdevs, vm->def->nhostdevs + 1) < 0) {
>>> +        virReportOOMError();
>>> +        goto cleanup;
>>> +    }
>>> +
>>> +    qemuDomainObjEnterMonitor(driver, vm);
>>> +    if ((ret = qemuMonitorAddDrive(priv->mon, drvstr)) == 0) {
>>> +        if ((ret = qemuMonitorAddDevice(priv->mon, devstr)) < 0) {
>>> +            VIR_WARN("qemuMonitorAddDevice failed on %s (%s)",
>>> +                     drvstr, devstr);
>>> +            qemuMonitorDriveDel(priv->mon, drvstr);
>>> +        }
>>> +    }
>>> +    qemuDomainObjExitMonitor(driver, vm);
>>> +
>>> +    virDomainAuditHostdev(vm, hostdev, "attach", ret == 0);
>> It may be better to more closely follow code flow of other modules as I
>> think you could be missing a nuance of a failure mode by trying to be
>> more generic.  Just check all callers of AddDrive and AddDevice...
>>
>>> +    if (ret < 0)
>>> +        goto cleanup;
>>> +
>>> +    vm->def->hostdevs[vm->def->nhostdevs++] = hostdev;
>>> +
>>> +    ret = 0;
>>> +cleanup:
>>> +    if (ret < 0)
>>> +        qemuDomainReAttachHostScsiDevices(driver, vm->def->name,
>>> &hostdev, 1);
>>> +    VIR_FREE(drvstr);
>>> +    VIR_FREE(devstr);
>>> +    return ret;
>>> +}
>>> +
>>>   int qemuDomainAttachHostDevice(virQEMUDriverPtr driver,
>>>                                  virDomainObjPtr vm,
>>>                                  virDomainHostdevDefPtr hostdev)
>>> @@ -1225,6 +1293,12 @@ int
>>> qemuDomainAttachHostDevice(virQEMUDriverPtr driver,
>>>               goto error;
>>>           break;
>>>   +    case VIR_DOMAIN_HOSTDEV_SUBSYS_TYPE_SCSI:
>>> +        if (qemuDomainAttachHostScsiDevice(driver, vm,
>>> +                                           hostdev) < 0)
>>> +            goto error;
>>> +        break;
>>> +
>>>       default:
>>>           virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
>>>                          _("hostdev subsys type '%s' not supported"),
>>> @@ -2441,11 +2515,59 @@
>>> qemuDomainDetachHostUsbDevice(virQEMUDriverPtr driver,
>>>       return ret;
>>>   }
>>>   -static
>>> -int qemuDomainDetachThisHostDevice(virQEMUDriverPtr driver,
>>> -                                   virDomainObjPtr vm,
>>> -                                   virDomainHostdevDefPtr detach,
>>> -                                   int idx)
>>> +static int
>>> +qemuDomainDetachHostScsiDevice(virQEMUDriverPtr driver,
>>> +                               virDomainObjPtr vm,
>>> +                               virDomainHostdevDefPtr detach)
>>> +{
>>> +    qemuDomainObjPrivatePtr priv = vm->privateData;
>>> +    char *drvstr = NULL;
>>> +    char *devstr = NULL;
>>> +    int ret = -1;
>>> +
>>> +    if (!detach->info->alias) {
>>> +        virReportError(VIR_ERR_OPERATION_FAILED,
>>> +                       "%s", _("device cannot be detached without a
>>> device alias"));
>>> +        return -1;
>>> +    }
>>> +
>>> +    if (!virQEMUCapsGet(priv->qemuCaps, QEMU_CAPS_DEVICE)) {
>>> +        virReportError(VIR_ERR_OPERATION_FAILED,
>>> +                       "%s", _("device cannot be detached with this
>>> QEMU version"));
>>> +        return -1;
>>> +    }
>>> +
>>> +    if (!(drvstr = qemuBuildSCSIHostdevDrvStr(detach, priv->qemuCaps)))
>>> +        goto cleanup;
>>> +    if (!(devstr = qemuBuildSCSIHostdevDevStr(vm->def, detach,
>>> priv->qemuCaps)))
>>> +        goto cleanup;
>>> +
>>> +    qemuDomainObjEnterMonitor(driver, vm);
>>> +    if ((ret = qemuMonitorDelDevice(priv->mon, detach->info->alias))
>>> == 0) {
>>> +        if ((ret = qemuMonitorDriveDel(priv->mon, drvstr)) < 0) {
>>> +            VIR_WARN("qemuMonitorDriveDel failed on %s (%s)",
>>> +                     detach->info->alias, drvstr);
>>> +            qemuMonitorAddDevice(priv->mon, devstr);
>> Coverity complains right here about no checking of return status:
>>
>> (9) Event check_return:     Calling function
>> "qemuMonitorAddDevice(qemuMonitorPtr, char const *)" without checking
>> return value (as is done elsewhere 8 out of 9 times).
>>
>>
>> As with attach, the flow of this code is a bit different than other
>> places where DelDevice() and DriveDel() are called - I would think you
>> may want to follow those other models more closely...
>>
>>
> I think you meant keeping the original error? here is the diff:
> 

Right, seems better now and the visual inspection regarding the coverity
complaint is cleaned up...

ACK

John