passthrough/stubdom: clean up hypercall privilege checking

This patch adds securty checks for pci passthrough related hypercalls
to enforce that the current domain owns the resources that it is about
to remap. It also adds a call to xc_assign_device to xend and removes
the PRIVILEGED_STUBDOMS flags.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>

tools/python/xen/xend/server/pciif.py

@@ -444,7 +444,15 @@ class PciController(DevController):
         # For hvm guest, (from c/s 19679 on) assigning device statically and
         # dynamically both go through reconfigureDevice(), so HERE the
         # setupOneDevice() is not necessary.
-        if not self.vm.info.is_hvm():
+        if self.vm.info.is_hvm():
+            for pci_dev in pci_dev_list:
+                # Setup IOMMU device assignment
+                bdf = xc.assign_device(self.getDomid(), pci_dict_to_xc_str(pci_dev))
+                pci_str = pci_dict_to_bdf_str(pci_dev)
+                if bdf > 0:
+                    raise VmError("Failed to assign device to IOMMU (%s)" % pci_str)
+                log.debug("pci: assign device %s" % pci_str)
+        else :
             for d in pci_dev_list:
                 self.setupOneDevice(d)
         wPath = '/local/domain/0/backend/pci/%u/0/aerState' % (self.getDomid())