Source code for qubes.ext.pci

#
# The Qubes OS Project, https://www.qubes-os.org/
#
# Copyright (C) 2016  Marek Marczykowski-Górecki
#                                   <[email protected]>
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, see <https://www.gnu.org/licenses/>.
#

''' Qubes PCI Extensions '''

import functools
import os
import re
import subprocess
import libvirt
import lxml
import lxml.etree

import qubes.devices
import qubes.ext

#: cache of PCI device classes
pci_classes = None


def load_pci_classes():
    ''' List of known device classes, subclasses and programming interfaces. '''
    # Syntax:
    # C class       class_name
    #       subclass        subclass_name           <-- single tab
    #               prog-if  prog-if_name   <-- two tabs
    result = {}
    with open('/usr/share/hwdata/pci.ids',
            encoding='utf-8', errors='ignore') as pciids:
        class_id = None
        subclass_id = None
        for line in pciids.readlines():
            line = line.rstrip()
            if line.startswith('\t\t') and class_id and subclass_id:
                (progif_id, _, class_name) = line[2:].split(' ', 2)
                result[class_id + subclass_id + progif_id] = \
                    class_name
            elif line.startswith('\t') and class_id:
                (subclass_id, _, class_name) = line[1:].split(' ', 2)
                # store both prog-if specific entry and generic one
                result[class_id + subclass_id + '00'] = \
                    class_name
                result[class_id + subclass_id] = \
                    class_name
            elif line.startswith('C '):
                (_, class_id, _, class_name) = line.split(' ', 3)
                result[class_id + '0000'] = class_name
                result[class_id + '00'] = class_name
                subclass_id = None

    return result


def pcidev_class(dev_xmldesc):
    sysfs_path = dev_xmldesc.findtext('path')
    assert sysfs_path
    try:
        with open(sysfs_path + '/class') as f_class:
            class_id = f_class.read().strip()
    except OSError:
        return "Unknown"

    if not qubes.ext.pci.pci_classes:
        qubes.ext.pci.pci_classes = load_pci_classes()
    if class_id.startswith('0x'):
        class_id = class_id[2:]
    try:
        # ignore prog-if
        return qubes.ext.pci.pci_classes[class_id[0:4]]
    except KeyError:
        return "Unknown"


def attached_devices(app):
    """Return map device->domain-name for all currently attached devices"""

    # Libvirt do not expose nice API to query where the device is
    # attached. The only way would be to query _all_ the domains (
    # each with separate libvirt call) and look if the device is
    # there. Horrible waste of resources.
    # Instead, do this on much lower level - xenstore info for
    # xen-pciback driver, where we get all the info at once

    xs = app.vmm.xs
    devices = {}
    for domid in xs.ls('', 'backend/pci') or []:
        for devid in xs.ls('', 'backend/pci/' + domid) or []:
            devpath = 'backend/pci/' + domid + '/' + devid
            domain_name = xs.read('', devpath + '/domain')
            try:
                domain = app.domains[domain_name]
            except KeyError:
                # unknown domain - maybe from another qubes.xml?
                continue
            devnum = xs.read('', devpath + '/num_devs')
            for dev in range(int(devnum)):
                dbdf = xs.read('', devpath + '/dev-' + str(dev))
                bdf = dbdf[len('0000:'):]
                devices[bdf.replace(':', '_')] = domain

    return devices


def _device_desc(hostdev_xml):
    return '{devclass}: {vendor} {product}'.format(
        devclass=pcidev_class(hostdev_xml),
        vendor=hostdev_xml.findtext('capability/vendor'),
        product=hostdev_xml.findtext('capability/product'),
    )


class PCIDevice(qubes.devices.DeviceInfo):
    # pylint: disable=too-few-public-methods
    regex = re.compile(
        r'^(?P<bus>[0-9a-f]+)_(?P<device>[0-9a-f]+)\.(?P<function>[0-9a-f]+)$')
    _libvirt_regex = re.compile(
        r'^pci_0000_(?P<bus>[0-9a-f]+)_(?P<device>[0-9a-f]+)_'
        r'(?P<function>[0-9a-f]+)$')

    def __init__(self, backend_domain, ident, libvirt_name=None):
        if libvirt_name:
            dev_match = self._libvirt_regex.match(libvirt_name)
            assert dev_match
            ident = '{bus}_{device}.{function}'.format(**dev_match.groupdict())

        super(PCIDevice, self).__init__(backend_domain, ident, None)

        # lazy loading
        self._description = None

    @property
    def libvirt_name(self):
        # pylint: disable=no-member
        # noinspection PyUnresolvedReferences
        return 'pci_0000_{}_{}_{}'.format(self.bus, self.device, self.function)

    @property
    def description(self):
        if self._description is None:
            hostdev_details = \
                self.backend_domain.app.vmm.libvirt_conn.nodeDeviceLookupByName(
                    self.libvirt_name
                )
            self._description = _device_desc(lxml.etree.fromstring(
                hostdev_details.XMLDesc()))
        return self._description

    @property
    def frontend_domain(self):
        # TODO: cache this
        all_attached = attached_devices(self.backend_domain.app)
        return all_attached.get(self.ident, None)


[docs]class PCIDeviceExtension(qubes.ext.Extension): def __init__(self): super(PCIDeviceExtension, self).__init__() # lazy load this self.pci_classes = {} @qubes.ext.handler('device-list:pci') def on_device_list_pci(self, vm, event): # pylint: disable=unused-argument,no-self-use # only dom0 expose PCI devices if vm.qid != 0: return for dev in vm.app.vmm.libvirt_conn.listAllDevices(): if 'pci' not in dev.listCaps(): continue xml_desc = lxml.etree.fromstring(dev.XMLDesc()) libvirt_name = xml_desc.findtext('name') yield PCIDevice(vm, None, libvirt_name=libvirt_name) @qubes.ext.handler('device-get:pci') def on_device_get_pci(self, vm, event, ident): # pylint: disable=unused-argument,no-self-use if not vm.app.vmm.offline_mode: yield _cache_get(vm, ident) @qubes.ext.handler('device-list-attached:pci') def on_device_list_attached(self, vm, event, **kwargs): # pylint: disable=unused-argument,no-self-use if not vm.is_running() or isinstance(vm, qubes.vm.adminvm.AdminVM): return xml_desc = lxml.etree.fromstring(vm.libvirt_domain.XMLDesc()) for hostdev in xml_desc.findall('devices/hostdev'): if hostdev.get('type') != 'pci': continue address = hostdev.find('source/address') bus = address.get('bus')[2:] device = address.get('slot')[2:] function = address.get('function')[2:] ident = '{bus}_{device}.{function}'.format( bus=bus, device=device, function=function, ) yield (PCIDevice(vm.app.domains[0], ident), {}) @qubes.ext.handler('device-pre-attach:pci') def on_device_pre_attached_pci(self, vm, event, device, options): # pylint: disable=unused-argument if not os.path.exists('/sys/bus/pci/devices/0000:{}'.format( device.ident.replace('_', ':'))): raise qubes.exc.QubesException( 'Invalid PCI device: {}'.format(device.ident)) if vm.virt_mode == 'pvh': raise qubes.exc.QubesException( "Can't attach PCI device to VM in pvh mode") if not vm.is_running(): return try: device = _cache_get(device.backend_domain, device.ident) self.bind_pci_to_pciback(vm.app, device) vm.libvirt_domain.attachDevice( vm.app.env.get_template('libvirt/devices/pci.xml').render( device=device, vm=vm, options=options)) except subprocess.CalledProcessError as e: vm.log.exception('Failed to attach PCI device {!r} on the fly,' ' changes will be seen after VM restart.'.format( device.ident), e) @qubes.ext.handler('device-pre-detach:pci') def on_device_pre_detached_pci(self, vm, event, device): # pylint: disable=unused-argument,no-self-use if not vm.is_running(): return # this cannot be converted to general API, because there is no # provision in libvirt for extracting device-side BDF; we need it for # qubes.DetachPciDevice, which unbinds driver, not to oops the kernel device = _cache_get(device.backend_domain, device.ident) p = subprocess.Popen(['xl', 'pci-list', str(vm.xid)], stdout=subprocess.PIPE) result = p.communicate()[0].decode() m = re.search(r'^(\d+.\d+)\s+0000:{}$'.format(device.ident.replace( '_', ':')), result, flags=re.MULTILINE) if not m: vm.log.error('Device %s already detached', device.ident) return vmdev = m.group(1) try: vm.run_service('qubes.DetachPciDevice', user='root', input='00:{}'.format(vmdev)) vm.libvirt_domain.detachDevice( vm.app.env.get_template('libvirt/devices/pci.xml').render( device=device, vm=vm)) except (subprocess.CalledProcessError, libvirt.libvirtError) as e: vm.log.exception('Failed to detach PCI device {!r} on the fly,' ' changes will be seen after VM restart.'.format( device.ident), e) raise @qubes.ext.handler('domain-pre-start') def on_domain_pre_start(self, vm, _event, **_kwargs): # Bind pci devices to pciback driver for assignment in vm.devices['pci'].persistent(): device = _cache_get(assignment.backend_domain, assignment.ident) self.bind_pci_to_pciback(vm.app, device) @staticmethod def bind_pci_to_pciback(app, device): '''Bind PCI device to pciback driver. :param qubes.devices.PCIDevice device: device to attach Devices should be unbound from their normal kernel drivers and bound to the dummy driver, which allows for attaching them to a domain. ''' try: node = app.vmm.libvirt_conn.nodeDeviceLookupByName( device.libvirt_name) except libvirt.libvirtError as e: if e.get_error_code() == libvirt.VIR_ERR_NO_NODE_DEVICE: raise qubes.exc.QubesException( 'PCI device {!s} does not exist'.format( device)) raise try: node.dettach() except libvirt.libvirtError as e: if e.get_error_code() == libvirt.VIR_ERR_INTERNAL_ERROR: # allreaddy dettached pass else: raise
@functools.lru_cache(maxsize=None) def _cache_get(vm, ident): ''' Caching wrapper around `PCIDevice(vm, ident)`. ''' return PCIDevice(vm, ident)