qubes/ext/pci: implement pci-no-strict-reset/BDF feature

Instead of old per-VM flag 'pci_strictreset', now implement this as
per-device flag using features. To not fail on particular device
assignment set 'pci-no-strict-reset/DEVICE-BDF' to True. For
example 'pci-no-strict-reset/00:1b.0'.

QubesOS/qubes-issues#2257

qubes/ext/pci.py

@@ -231,7 +231,7 @@ class PCIDeviceExtension(qubes.ext.Extension):
             self.bind_pci_to_pciback(vm.app, device)
             vm.libvirt_domain.attachDevice(
                 vm.app.env.get_template('libvirt/devices/pci.xml').render(
-                    device=device))
+                    device=device, vm=vm))
         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(
@@ -261,7 +261,7 @@ class PCIDeviceExtension(qubes.ext.Extension):
                 user='root', input='00:{}'.format(vmdev))
             vm.libvirt_domain.detachDevice(
                 vm.app.env.get_template('libvirt/devices/pci.xml').render(
-                    device=device))
+                    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(

qubes/tests/int/devices_pci.py

@@ -50,6 +50,7 @@ class TC_00_Devices_PCI(qubes.tests.SystemTestsMixin,
                 label='red',
             )
             self.vm.create_on_disk()
+            self.vm.features['pci-no-strict-reset/' + pcidev] = True
             self.app.save()
 
     def test_000_list(self):

templates/libvirt/devices/pci.xml

@@ -1,4 +1,8 @@
-<hostdev type="pci" managed="yes">
+<hostdev type="pci" managed="yes"
+{% if vm.features.get('pci-no-strict-reset/' + device.ident, False) %}
+ nostrictreset="yes"
+{% endif %}
+>
     <source>
         <address
             bus="0x{{ device.bus }}"