[Xen-changelog] [xen-unstable] ia64: PV driver domains - ugly python hacks

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1218189220 -3600
# Node ID f62a61cd95f54358bc20a86411771acf6ed74ea0
# Parent  3ab0e76fb8e2e42164adc4b393254ebbae3cc9ee
ia64: PV driver domains - ugly python hacks

x86 IOMMU support added a lot of assumptions about what PCI buses look
like and where to find bridge devices.  On ia64, we don't yet have
virtualization friendly IOMMUs, so for the moment, we just want to
keep "unsafe" PV PCI pass through working as well as it did in Xen
3.2. Looking at the code, it almost seems like x86 has thrown out
support for the old style driver domain.  Things that don't
necessarily work on every PCI compliant architecture:

      * You can't assume that just because there's a device at 01:01.0
        that there's also a bridge at 01:00.0 and blow-up when you
        don't find it.  On HP ia64 boxes, PCI root bridges are not
        necessarily exposed as a PCI device.  This pretty much means
        we can't call into any of the "FLR" code paths.
      * BAR alignment: it's hard to have BAR alignment when your page
        size is 16k.  This wasn't a requirement for previous PV driver
        domains, so I assume it's only for IOMMU support.

This is ugly, so I'm open to suggestions.  It seems that all of these
architecture checks could be replaced by checking some "iommu_present"
variable to test whether the extra requirements are necessary.

Signed-off-by: Alex Williamson <alex.williamson@xxxxxx>
---
 tools/python/xen/xend/server/pciif.py |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)

diff -r 3ab0e76fb8e2 -r f62a61cd95f5 tools/python/xen/xend/server/pciif.py
--- a/tools/python/xen/xend/server/pciif.py     Fri Aug 08 10:48:48 2008 +0100
+++ b/tools/python/xen/xend/server/pciif.py     Fri Aug 08 10:53:40 2008 +0100
@@ -21,6 +21,7 @@ import time
 import time
 
 from xen.xend import sxp
+from xen.xend import arch
 from xen.xend.XendError import VmError
 from xen.xend.XendLogging import log
 
@@ -284,12 +285,13 @@ class PciController(DevController):
                     "bind your slot/device to the PCI backend using sysfs" \
                     )%(dev.name))
 
-        if dev.has_non_page_aligned_bar:
+        if dev.has_non_page_aligned_bar and arch.type != "ia64":
             raise VmError("pci: %: non-page-aligned MMIO BAR found." % 
dev.name)
 
         self.CheckSiblingDevices(fe_domid, dev)
 
-        dev.do_FLR()
+        if arch.type != "ia64":
+            dev.do_FLR()
 
         PCIQuirk(dev.vendor, dev.device, dev.subvendor, dev.subdevice, domain, 
                 bus, slot, func)
@@ -395,7 +397,7 @@ class PciController(DevController):
                                     ' the same guest with %s'
                                 raise VmError(err_msg % (f, dev.name))
             elif dev.dev_type == DEV_TYPE_PCI:
-                if dev.bus == 0:
+                if dev.bus == 0 or arch.type == "ia64":
                     if not dev.pci_af_flr:
                         # We cope with this case by using the Dstate transition
                         # method for now.

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