PCI: vmd: Filter resource type bits from shadow register

Versions of VMD with the Host Physical Address shadow register use this
register to calculate the bus address offset needed to do guest
passthrough of the domain. This register shadows the Host Physical
Address registers including the resource type bits. After calculating
the offset, the extra resource type bits lead to the VMD resources being
over-provisioned at the front and under-provisioned at the back.

Example:
pci 10000:80:02.0: reg 0x10: [mem 0xf801fffc-0xf803fffb 64bit]

Expected:
pci 10000:80:02.0: reg 0x10: [mem 0xf8020000-0xf803ffff 64bit]

If other devices are mapped in the over-provisioned front, it could lead
to resource conflict issues with VMD or those devices.

Link: https://lore.kernel.org/r/20200528030240.16024-3-jonathan.derrick@intel.com
Fixes: a1a30170138c9 ("PCI: vmd: Fix shadow offsets to reflect spec changes")
Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>

diff --git a/drivers/pci/controller/vmd.c b/drivers/pci/controller/vmd.c
index dac91d60701de2a40d75a2ebc38043d3b77c42fe..e386d4eac4070dc241ac3a10cc183687d2ce2126 100644 (file)
--- a/drivers/pci/controller/vmd.c
+++ b/drivers/pci/controller/vmd.c
@@ -445,9 +445,11 @@ static int vmd_enable_domain(struct vmd_dev *vmd, unsigned long features)
                        if (!membar2)
                                return -ENOMEM;
                        offset[0] = vmd->dev->resource[VMD_MEMBAR1].start -
-                                       readq(membar2 + MB2_SHADOW_OFFSET);
+                                       (readq(membar2 + MB2_SHADOW_OFFSET) &
+                                        PCI_BASE_ADDRESS_MEM_MASK);
                        offset[1] = vmd->dev->resource[VMD_MEMBAR2].start -
-                                       readq(membar2 + MB2_SHADOW_OFFSET + 8);
+                                       (readq(membar2 + MB2_SHADOW_OFFSET + 8) &
+                                        PCI_BASE_ADDRESS_MEM_MASK);
                        pci_iounmap(vmd->dev, membar2);
                }
        }