# Copyright (c) 2013 Intel, Inc. # Copyright (c) 2013 OpenStack Foundation # All Rights Reserved. # # Licensed under the Apache License, Version 2.0 (the "License"); you may # not use this file except in compliance with the License. You may obtain # a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, WITHOUT # WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the # License for the specific language governing permissions and limitations # under the License. import collections from oslo_config import cfg from oslo_log import log as logging from oslo_serialization import jsonutils from nova import exception from nova import objects from nova.objects import fields from nova.pci import stats from nova.pci import whitelist CONF = cfg.CONF LOG = logging.getLogger(__name__) class PciDevTracker(object): """Manage pci devices in a compute node. This class fetches pci passthrough information from hypervisor and tracks the usage of these devices. It's called by compute node resource tracker to allocate and free devices to/from instances, and to update the available pci passthrough device information from the hypervisor periodically. The `pci_devs` attribute of this class is the in-memory "master copy" of all devices on each compute host, and all data changes that happen when claiming/allocating/freeing devices HAVE TO be made against instances contained in `pci_devs` list, because they are periodically flushed to the DB when the save() method is called. It is unsafe to fetch PciDevice objects elsewhere in the code for update purposes as those changes will end up being overwritten when the `pci_devs` are saved. """ def __init__(self, context, node_id=None): """Create a pci device tracker. If a node_id is passed in, it will fetch pci devices information from database, otherwise, it will create an empty devices list and the resource tracker will update the node_id information later. """ super(PciDevTracker, self).__init__() self.stale = {} self.node_id = node_id self.dev_filter = whitelist.Whitelist(CONF.pci.passthrough_whitelist) self.stats = stats.PciDeviceStats(dev_filter=self.dev_filter) self._context = context if node_id: self.pci_devs = objects.PciDeviceList.get_by_compute_node( context, node_id) else: self.pci_devs = objects.PciDeviceList(objects=[]) self._build_device_tree(self.pci_devs) self._initial_instance_usage() def _initial_instance_usage(self): self.allocations = collections.defaultdict(list) self.claims = collections.defaultdict(list) for dev in self.pci_devs: uuid = dev.instance_uuid if dev.status == fields.PciDeviceStatus.CLAIMED: self.claims[uuid].append(dev) elif dev.status == fields.PciDeviceStatus.ALLOCATED: self.allocations[uuid].append(dev) elif dev.status == fields.PciDeviceStatus.AVAILABLE: self.stats.add_device(dev) def save(self, context): for dev in self.pci_devs: if dev.obj_what_changed(): with dev.obj_alternate_context(context): dev.save() if dev.status == fields.PciDeviceStatus.DELETED: self.pci_devs.objects.remove(dev) @property def pci_stats(self): return self.stats def update_devices_from_hypervisor_resources(self, devices_json): """Sync the pci device tracker with hypervisor information. To support pci device hot plug, we sync with the hypervisor periodically, fetching all devices information from hypervisor, update the tracker and sync the DB information. Devices should not be hot-plugged when assigned to a guest, but possibly the hypervisor has no such guarantee. The best we can do is to give a warning if a device is changed or removed while assigned. :param devices_json: The JSON-ified string of device information that is returned from the virt driver's get_available_resource() call in the pci_passthrough_devices key. """ devices = [] for dev in jsonutils.loads(devices_json): if self.dev_filter.device_assignable(dev): devices.append(dev) self._set_hvdevs(devices) @staticmethod def _build_device_tree(all_devs): """Build a tree of devices that represents parent-child relationships. We need to have the relationships set up so that we can easily make all the necessary changes to parent/child devices without having to figure it out at each call site. This method just adds references to relevant instances already found in `pci_devs` to `child_devices` and `parent_device` fields of each one. Currently relationships are considered for SR-IOV PFs/VFs only. """ # Ensures that devices are ordered in ASC so VFs will come # after their PFs. all_devs.sort(key=lambda x: x.address) parents = {} for dev in all_devs: if dev.status in (fields.PciDeviceStatus.REMOVED, fields.PciDeviceStatus.DELETED): # NOTE(ndipanov): Removed devs are pruned from # self.pci_devs on save() so we need to make sure we # are not looking at removed ones as we may build up # the tree sooner than they are pruned. continue if dev.dev_type == fields.PciDeviceType.SRIOV_PF: dev.child_devices = [] parents[dev.address] = dev elif dev.dev_type == fields.PciDeviceType.SRIOV_VF: dev.parent_device = parents.get(dev.parent_addr) if dev.parent_device: parents[dev.parent_addr].child_devices.append(dev) def _set_hvdevs(self, devices): exist_addrs = set([dev.address for dev in self.pci_devs]) new_addrs = set([dev['address'] for dev in devices]) for existed in self.pci_devs: if existed.address in exist_addrs - new_addrs: # Remove previously tracked PCI devices that are either # no longer reported by the hypervisor or have been removed # from the pci whitelist. try: existed.remove() except exception.PciDeviceInvalidStatus as e: LOG.warning("Unable to remove device with %(status)s " "ownership %(instance_uuid)s because of " "%(pci_exception)s. " "Check your [pci]passthrough_whitelist " "configuration to make sure this allocated " "device is whitelisted. If you have removed " "the device from the whitelist intentionally " "or the device is no longer available on the " "host you will need to delete the server or " "migrate it to another host to silence this " "warning.", {'status': existed.status, 'instance_uuid': existed.instance_uuid, 'pci_exception': e.format_message()}) # NOTE(sean-k-mooney): the device may not be tracked for # two reasons: first the device could have been removed # from the host or second the whitelist could have been # updated. While force removing may seam reasonable, if # the device is allocated to a vm, force removing the # device entry from the resource tracker can prevent the vm # from rebooting. If the PCI device was removed due to an # update to the PCI whitelist which was later reverted, # removing the entry from the database and adding it back # later may lead to the scheduler incorrectly selecting # this host and the ResourceTracker assigning the PCI # device to a second vm. To prevent this bug we skip # deleting the device from the db in this iteration and # will try again on the next sync. continue else: # Note(yjiang5): no need to update stats if an assigned # device is hot removed. self.stats.remove_device(existed) else: # Update tracked devices. new_value = next((dev for dev in devices if dev['address'] == existed.address)) new_value['compute_node_id'] = self.node_id if existed.status in (fields.PciDeviceStatus.CLAIMED, fields.PciDeviceStatus.ALLOCATED): # Pci properties may change while assigned because of # hotplug or config changes. Although normally this should # not happen. # As the devices have been assigned to an instance, # we defer the change till the instance is destroyed. # We will not sync the new properties with database # before that. # TODO(yjiang5): Not sure if this is a right policy, but # at least it avoids some confusion and, if needed, # we can add more action like killing the instance # by force in future. self.stale[new_value['address']] = new_value else: existed.update_device(new_value) self.stats.update_device(existed) # Track newly discovered devices. for dev in [dev for dev in devices if dev['address'] in new_addrs - exist_addrs]: dev['compute_node_id'] = self.node_id dev_obj = objects.PciDevice.create(self._context, dev) self.pci_devs.objects.append(dev_obj) self.stats.add_device(dev_obj) self._build_device_tree(self.pci_devs) def _claim_instance(self, context, pci_requests, instance_numa_topology): instance_cells = None if instance_numa_topology: instance_cells = instance_numa_topology.cells devs = self.stats.consume_requests(pci_requests.requests, instance_cells) if not devs: return None instance_uuid = pci_requests.instance_uuid for dev in devs: dev.claim(instance_uuid) if instance_numa_topology and any( dev.numa_node is None for dev in devs): LOG.warning("Assigning a pci device without numa affinity to " "instance %(instance)s which has numa topology", {'instance': instance_uuid}) return devs def _allocate_instance(self, instance, devs): for dev in devs: dev.allocate(instance) def allocate_instance(self, instance): devs = self.claims.pop(instance['uuid'], []) self._allocate_instance(instance, devs) if devs: self.allocations[instance['uuid']] += devs def claim_instance(self, context, pci_requests, instance_numa_topology): devs = [] if self.pci_devs and pci_requests.requests: instance_uuid = pci_requests.instance_uuid devs = self._claim_instance(context, pci_requests, instance_numa_topology) if devs: self.claims[instance_uuid] = devs return devs def free_device(self, dev, instance): """Free device from pci resource tracker :param dev: cloned pci device object that needs to be free :param instance: the instance that this pci device is allocated to """ for pci_dev in self.pci_devs: # Find the matching pci device in the pci resource tracker. # Once found, free it. if dev.id == pci_dev.id and dev.instance_uuid == instance['uuid']: self._remove_device_from_pci_mapping( instance['uuid'], pci_dev, self.allocations) self._remove_device_from_pci_mapping( instance['uuid'], pci_dev, self.claims) self._free_device(pci_dev) break def _remove_device_from_pci_mapping( self, instance_uuid, pci_device, pci_mapping): """Remove a PCI device from allocations or claims. If there are no more PCI devices, pop the uuid. """ pci_devices = pci_mapping.get(instance_uuid, []) if pci_device in pci_devices: pci_devices.remove(pci_device) if len(pci_devices) == 0: pci_mapping.pop(instance_uuid, None) def _free_device(self, dev, instance=None): freed_devs = dev.free(instance) stale = self.stale.pop(dev.address, None) if stale: dev.update_device(stale) for dev in freed_devs: self.stats.add_device(dev) def free_instance_allocations(self, context, instance): """Free devices that are in ALLOCATED state for instance. :param context: user request context (nova.context.RequestContext) :param instance: instance object """ if self.allocations.pop(instance['uuid'], None): for dev in self.pci_devs: if (dev.status == fields.PciDeviceStatus.ALLOCATED and dev.instance_uuid == instance['uuid']): self._free_device(dev) def free_instance_claims(self, context, instance): """Free devices that are in CLAIMED state for instance. :param context: user request context (nova.context.RequestContext) :param instance: instance object """ if self.claims.pop(instance['uuid'], None): for dev in self.pci_devs: if (dev.status == fields.PciDeviceStatus.CLAIMED and dev.instance_uuid == instance['uuid']): self._free_device(dev) def free_instance(self, context, instance): """Free devices that are in CLAIMED or ALLOCATED state for instance. :param context: user request context (nova.context.RequestContext) :param instance: instance object """ # Note(yjiang5): When an instance is resized, the devices in the # destination node are claimed to the instance in prep_resize stage. # However, the instance contains only allocated devices # information, not the claimed one. So we can't use # instance['pci_devices'] to check the devices to be freed. self.free_instance_allocations(context, instance) self.free_instance_claims(context, instance) def update_pci_for_instance(self, context, instance, sign): """Update PCI usage information if devices are de/allocated. """ if not self.pci_devs: return if sign == -1: self.free_instance(context, instance) if sign == 1: self.allocate_instance(instance) def clean_usage(self, instances, migrations, orphans): """Remove all usages for instances not passed in the parameter. The caller should hold the COMPUTE_RESOURCE_SEMAPHORE lock """ existed = set(inst['uuid'] for inst in instances) existed |= set(mig['instance_uuid'] for mig in migrations) existed |= set(inst['uuid'] for inst in orphans) # need to copy keys, because the dict is modified in the loop body for uuid in list(self.claims): if uuid not in existed: devs = self.claims.pop(uuid, []) for dev in devs: self._free_device(dev) # need to copy keys, because the dict is modified in the loop body for uuid in list(self.allocations): if uuid not in existed: devs = self.allocations.pop(uuid, []) for dev in devs: self._free_device(dev) def get_instance_pci_devs(inst, request_id=None): """Get the devices allocated to one or all requests for an instance. - For generic PCI request, the request id is None. - For sr-iov networking, the request id is a valid uuid - There are a couple of cases where all the PCI devices allocated to an instance need to be returned. Refer to libvirt driver that handles soft_reboot and hard_boot of 'xen' instances. """ pci_devices = inst.pci_devices if pci_devices is None: return [] return [device for device in pci_devices if device.request_id == request_id or request_id == 'all']