iommu/vt-d: Don't reject NTB devices due to scope mismatch
On a system with an Intel PCIe port configured as an NTB device, iommu
initialization fails with
DMAR: Device scope type does not match for 0000:80:03.0
This is because the DMAR table reports this device as having scope 2
(ACPI_DMAR_SCOPE_TYPE_BRIDGE):
[0A0h 0160 1] Device Scope Entry Type : 02
[0A1h 0161 1] Entry Length : 08
[0A2h 0162 2] Reserved : 0000
[0A4h 0164 1] Enumeration ID : 00
[0A5h 0165 1] PCI Bus Number : 80
[0A6h 0166 2] PCI Path : 03,00
but the device has a type 0 PCI header:
80:03.0 Bridge [0680]: Intel Corporation Device [8086:2f0d] (rev 02)
00: 86 80 0d 2f 00 00 10 00 02 00 80 06 10 00 80 00
10: 0c 00 c0 00 c0 38 00 00 0c 00 00 00 80 38 00 00
20: 00 00 00 c8 00 00 10 c8 00 00 00 00 86 80 00 00
30: 00 00 00 00 60 00 00 00 00 00 00 00 ff 01 00 00
VT-d works perfectly on this system, so there's no reason to bail out
on initialization due to this apparent scope mismatch. Use the class
0x0680 ("Other bridge device") as a heuristic for allowing DMAR
initialization for non-bridge PCI devices listed with scope bridge.
Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
diff --git a/drivers/iommu/dmar.c b/drivers/iommu/dmar.c
index 6a86b5d..2eff7b6 100644
--- a/drivers/iommu/dmar.c
+++ b/drivers/iommu/dmar.c
@@ -241,8 +241,20 @@
if (!dmar_match_pci_path(info, scope->bus, path, level))
continue;
- if ((scope->entry_type == ACPI_DMAR_SCOPE_TYPE_ENDPOINT) ^
- (info->dev->hdr_type == PCI_HEADER_TYPE_NORMAL)) {
+ /*
+ * We expect devices with endpoint scope to have normal PCI
+ * headers, and devices with bridge scope to have bridge PCI
+ * headers. However PCI NTB devices may be listed in the
+ * DMAR table with bridge scope, even though they have a
+ * normal PCI header. NTB devices are identified by class
+ * "BRIDGE_OTHER" (0680h) - we don't declare a socpe mismatch
+ * for this special case.
+ */
+ if ((scope->entry_type == ACPI_DMAR_SCOPE_TYPE_ENDPOINT &&
+ info->dev->hdr_type != PCI_HEADER_TYPE_NORMAL) ||
+ (scope->entry_type == ACPI_DMAR_SCOPE_TYPE_BRIDGE &&
+ (info->dev->hdr_type == PCI_HEADER_TYPE_NORMAL &&
+ info->dev->class >> 8 != PCI_CLASS_BRIDGE_OTHER))) {
pr_warn("Device scope type does not match for %s\n",
pci_name(info->dev));
return -EINVAL;