[Kimchi-devel] [PATCH v7 4/4] Host device passthrough: List VMs that are holding a host device

[Aline Manera]

On 07/09/2014 04:01 AM, Zhou Zheng Sheng wrote:
> Add a "vm_holders" sub-collection under host device resource, so the
> front-end can determine if a device is busy or not, and the user can
> know which VMs are holding the device.
>
> This patch scans all VM XML to check if a device is hold by a VM. Also
> adds a check to keep the host device assigned to only one VM.
>
> Example
>    curl -k -u root -H "Content-Type: application/json" \
>      -H "Accept: application/json" \
>      'https://127.0.0.1:8001/host/devices/usb_1_1_6/vm_holders'

You don't need to create a new resource for it
It should be a parameter of /host/devices/usb_1_1_6

Example:

GET /host/devices/usb_1_1_6
{
    ...
    holders: [vm1, vm2, ...]
}

> Should output a list like following.
>    [
>      {
>        "state":"shutoff",
>        "name":"fedora20"
>      },
>      {
>        "state":"running",
>        "name":"f20xfce-slave"
>      }
>    ]
>
> If there is no VM holding the device, it prints an empty list [].
>
> v5:
>    When assigning a device to VM, check if there are other VMs holding
> the device and raise an exception. Move the VMHoldersModel to
> vmhostdevs.py to avoid circular import problem.
>
> Signed-off-by: Zhou Zheng Sheng <zhshzhou at linux.vnet.ibm.com>
> ---
>   src/kimchi/control/host.py     |  7 +++++++
>   src/kimchi/i18n.py             |  2 ++
>   src/kimchi/model/vmhostdevs.py | 24 ++++++++++++++++++++++++
>   3 files changed, 33 insertions(+)
>
> diff --git a/src/kimchi/control/host.py b/src/kimchi/control/host.py
> index 15f2343..efc31ea 100644
> --- a/src/kimchi/control/host.py
> +++ b/src/kimchi/control/host.py
> @@ -110,11 +110,18 @@ class PassthroughAffectedDevices(Collection):
>           self.model_args = (device_id, )
>
>
> +class VMHolders(SimpleCollection):
> +    def __init__(self, model, device_id):
> +        super(VMHolders, self).__init__(model)
> +        self.model_args = (device_id, )
> +
> +
>   class Device(Resource):
>       def __init__(self, model, id):
>           super(Device, self).__init__(model, id)
>           self.passthrough_affected_devices = \
>               PassthroughAffectedDevices(self.model, id)
> +        self.vm_holders = VMHolders(self.model, id)
>
>       @property
>       def data(self):
> diff --git a/src/kimchi/i18n.py b/src/kimchi/i18n.py
> index bee734a..bbe40be 100644
> --- a/src/kimchi/i18n.py
> +++ b/src/kimchi/i18n.py
> @@ -96,6 +96,8 @@ messages = {
>                           "Please enable Intel VT-d or AMD IOMMU in your BIOS, then verify the Kernel is compiled with IOMMU support. "
>                           "For Intel CPU, add intel_iommu=on to your Kernel parameter in /boot/grub2/grub.conf. "
>                           "For AMD CPU, add iommu=pt iommu=1."),
> +    "KCHVMHDEV0004E": _("The host device %(dev_name)s should be assigned to just one VM. "
> +                        "Currently the following VM(s) are holding the device: %(names)s."),
>
>       "KCHVMIF0001E": _("Interface %(iface)s does not exist in virtual machine %(name)s"),
>       "KCHVMIF0002E": _("Network %(network)s specified for virtual machine %(name)s does not exist"),
> diff --git a/src/kimchi/model/vmhostdevs.py b/src/kimchi/model/vmhostdevs.py
> index 4569bd0..5b10bf6 100644
> --- a/src/kimchi/model/vmhostdevs.py
> +++ b/src/kimchi/model/vmhostdevs.py
> @@ -119,6 +119,11 @@ class VMHostDevsModel(object):
>               DevicesModel(conn=self.conn).get_list(_passthrough='true')
>           if dev_name not in eligible_dev_names:
>               raise InvalidParameter('KCHVMHDEV0002E', {'dev_name': dev_name})
> +        holders = VMHoldersModel(conn=self.conn).get_list(dev_name)
> +        if holders:
> +            names = ', '.join([holder['name'] for holder in holders])
> +            raise InvalidOperation('KCHVMHDEV0004E', {'dev_name': dev_name,
> +                                                      'names': names})
>
>       def create(self, vmid, params):
>           dev_name = params['name']
> @@ -297,3 +302,22 @@ class VMHostDevModel(object):
>                   xmlstr = etree.tostring(e)
>                   dom.detachDeviceFlags(
>                       xmlstr, get_vm_config_flag(dom, mode='all'))
> +
> +
> +class VMHoldersModel(object):
> +    def __init__(self, **kargs):
> +        self.conn = kargs['conn']
> +
> +    def get_list(self, device_id):
> +        devsmodel = VMHostDevsModel(conn=self.conn)
> +
> +        conn = self.conn.get()
> +        doms = conn.listAllDomains(0)
> +
> +        res = []
> +        for dom in doms:
> +            dom_name = dom.name()
> +            if device_id in devsmodel.get_list(dom_name):
> +                state = DOM_STATE_MAP[dom.info()[0]]
> +                res.append({"name": dom_name, "state": state})
> +        return res
>