[Kimchi-devel] [PATCH v6 2/4] Host device passthrough: List eligible device to passthrough
Zhou Zheng Sheng
zhshzhou at linux.vnet.ibm.com
Mon Jun 9 09:28:35 UTC 2014
This patch adds a '_passthrough=1' filter to /host/devices, so it can
filter and shows all devices eligible to passthrough to guest.
Theoretically, all PCI, USB and SCSI devices can be assigned to guest
directly. However usually all host devices form a tree, if we assign a
PCI port/SCSI controller/USB controller to guest, all devices/disks
under the controller are assigned as well. In this patch we only present
the "leaf" host devices to the user as potential passthrough devices.
In other word, the possible devices are wireless network interface, SD
card reader, camera, SCSI unit(disk or CD), and so on.
Linux kernel is able to recognize the host IOMMU group layout. If two
PCI devices are in the same IOMMU group, it means there are possible
interconnections between the devices, and the devices can talk to each
other bypassing IOMMU. This implies isolation is not pefect between those
devices, so all devices in a IOMMU group must be assigned to guest
together. On host that recognizes IOMMU groups, by accessing the URI
/host/devices/deviceX/passthrough_affected_devices, it returns a list
containing the devices in the same IOMMU group as deviceX.
How to test:
List all types of devices to passthrough
curl -k -u root -H "Content-Type: application/json" \
-H "Accept: application/json" \
'https://127.0.0.1:8001/host/devices?_passthrough=true'
List all eligible PCI devices to passthrough
/host/devices?_passthrough=true&_cap=pci
List all USB devices to passthrough
/host/devices?_passthrough=true&_cap=usb_device
List all SCSI devices to passthrough
/host/devices?_passthrough=true&_cap=scsi
List devices in the same IOMMU group as pci_0000_00_19_0
/host/devices/pci_0000_00_19_0/passthrough_affected_devices
v1:
v1 series does not contain this patch.
v2:
Deal with calculation "leaf" device and "affected" device.
v3 v4:
No change.
v5:
Change _passthrough=1 to _passthrough=true in the URI scheme. Filter
PCI devices according the PCI class.
v6:
Don't passthrough PCI device of class code 07. In modern
x86 machine, it's possible that
"6 Series/C200 Series Chipset Family MEI Controller" and
"6 Series/C200 Series Chipset Family KT Controller"
are of this class code. These two devices are not suitable to
passthrough to guest. We don't have simple and reliable way to
distinguish normal serial controller and host chipset XXX controller.
This type of PCI devices also include various serial, parallel, modem,
communication controller. Serial and parallel controllers can be
re-direct from ttyS0 to QEMU's pty using socat, and there is little
performance benefit to directly assign to guest. So it'k ok not to
passththrough PCI device of class code 07.
Signed-off-by: Zhou Zheng Sheng <zhshzhou at linux.vnet.ibm.com>
---
src/kimchi/control/host.py | 9 ++++
src/kimchi/hostdev.py | 107 +++++++++++++++++++++++++++++++++++++++++++++
src/kimchi/model/host.py | 17 ++++++-
3 files changed, 132 insertions(+), 1 deletion(-)
diff --git a/src/kimchi/control/host.py b/src/kimchi/control/host.py
index ebf1bed..15f2343 100644
--- a/src/kimchi/control/host.py
+++ b/src/kimchi/control/host.py
@@ -103,9 +103,18 @@ class Devices(Collection):
self.resource = Device
+class PassthroughAffectedDevices(Collection):
+ def __init__(self, model, device_id):
+ super(PassthroughAffectedDevices, self).__init__(model)
+ self.resource = Device
+ 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)
@property
def data(self):
diff --git a/src/kimchi/hostdev.py b/src/kimchi/hostdev.py
index d4c142d..f70154f 100644
--- a/src/kimchi/hostdev.py
+++ b/src/kimchi/hostdev.py
@@ -17,6 +17,8 @@
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+import os
+
from kimchi.model.libvirtconnection import LibvirtConnection
from kimchi.utils import kimchi_log
from kimchi.xmlutils import dictize
@@ -46,6 +48,108 @@ def _get_dev_info_tree(dev_infos):
return root
+def _strip_parents(devs, dev):
+ parent = dev['parent']
+ while parent is not None:
+ try:
+ parent_dev = devs.pop(parent)
+ except KeyError:
+ break
+
+ if (parent_dev['device_type'],
+ dev['device_type']) == ('usb_device', 'scsi'):
+ # For USB device containing mass storage, passthrough the
+ # USB device itself, not the SCSI unit.
+ devs.pop(dev['name'])
+ break
+
+ parent = parent_dev['parent']
+
+
+def _is_pci_qualified(pci_dev):
+ # PCI class such as bridge and storage controller are not suitable to
+ # passthrough to VM, so we make a whitelist and only passthrough PCI
+ # class in the list.
+
+ whitelist_pci_classes = {
+ # Refer to Linux Kernel code include/linux/pci_ids.h
+ 0x000000: { # Old PCI devices
+ 0x000100: None}, # Old VGA devices
+ 0x020000: None, # Network controller
+ 0x030000: None, # Display controller
+ 0x040000: None, # Multimedia device
+ 0x090000: None, # Inupt device
+ 0x0d0000: None, # Wireless controller
+ 0x0f0000: None, # Satellite communication controller
+ 0x100000: None, # Cryption controller
+ 0x110000: None, # Signal Processing controller
+ }
+
+ with open(os.path.join(pci_dev['path'], 'class')) as f:
+ pci_class = int(f.read(), 16)
+
+ try:
+ subclass = whitelist_pci_classes[pci_class & 0xff0000]
+ except KeyError:
+ return False
+
+ if subclass is None:
+ return True
+
+ if pci_class & 0xffff00 in subclass:
+ return True
+
+ return False
+
+
+def get_passthrough_dev_infos():
+ ''' Get devices eligible to be passed through to VM. '''
+
+ dev_infos = _get_all_host_dev_infos()
+ devs = dict([(dev_info['name'], dev_info) for dev_info in dev_infos])
+
+ for dev in dev_infos:
+ if dev['device_type'] in ('pci', 'usb_device', 'scsi'):
+ _strip_parents(devs, dev)
+
+ def is_eligible(dev):
+ if dev['device_type'] not in ('pci', 'usb_device', 'scsi'):
+ return False
+ if dev['device_type'] == 'pci':
+ return _is_pci_qualified(dev)
+ return True
+
+ return [dev for dev in devs.itervalues() if is_eligible(dev)]
+
+
+def get_affected_passthrough_devices(passthrough_dev):
+ devs = dict([(dev['name'], dev) for dev in _get_all_host_dev_infos()])
+
+ def get_iommu_group(dev_info):
+ try:
+ return int(dev_info['iommuGroup'])
+ except KeyError:
+ pass
+
+ parent = dev_info['parent']
+ while parent is not None:
+ try:
+ iommuGroup = int(devs[parent]['iommuGroup'])
+ except KeyError:
+ pass
+ else:
+ return iommuGroup
+ parent = devs[parent]['parent']
+
+ return -1
+
+ iommu_group = get_iommu_group(passthrough_dev)
+
+ return [dev for dev in get_passthrough_dev_infos()
+ if dev['name'] != passthrough_dev['name'] and
+ get_iommu_group(dev) == iommu_group]
+
+
def get_dev_info(node_dev):
''' Parse the node device XML string into dict according to
http://libvirt.org/formatnode.html. '''
@@ -206,4 +310,7 @@ def _format_dev_node(node):
if __name__ == '__main__':
+ from pprint import pprint
_print_host_dev_tree()
+ print 'Eligible passthrough devices:'
+ pprint(get_passthrough_dev_infos())
diff --git a/src/kimchi/model/host.py b/src/kimchi/model/host.py
index 1ea97f0..280aa53 100644
--- a/src/kimchi/model/host.py
+++ b/src/kimchi/model/host.py
@@ -247,7 +247,7 @@ class DevicesModel(object):
def __init__(self, **kargs):
self.conn = kargs['conn']
- def get_list(self, _cap=None):
+ def get_list(self, _cap=None, _passthrough=None):
conn = self.conn.get()
if _cap is None:
dev_names = [name.name() for name in conn.listAllDevices(0)]
@@ -256,6 +256,11 @@ class DevicesModel(object):
else:
# Get devices with required capability
dev_names = conn.listDevices(_cap, 0)
+
+ if _passthrough is not None and _passthrough.lower() == 'true':
+ passthrough_names = [
+ dev['name'] for dev in hostdev.get_passthrough_dev_infos()]
+ dev_names = list(set(dev_names) & set(passthrough_names))
return dev_names
def _get_devices_fc_host(self):
@@ -273,6 +278,16 @@ class DevicesModel(object):
return conn.listDevices('fc_host', 0)
+class PassthroughAffectedDevicesModel(object):
+ def __init__(self, **kargs):
+ self.conn = kargs['conn']
+
+ def get_list(self, device_id):
+ dev_info = DeviceModel(conn=self.conn).lookup(device_id)
+ affected = hostdev.get_affected_passthrough_devices(dev_info)
+ return [dev['name'] for dev in affected]
+
+
class DeviceModel(object):
def __init__(self, **kargs):
self.conn = kargs['conn']
--
1.9.3
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