If the device itself reports ATS in its PCIe capabilities, but the BIOS neglects to provide an ATSR structure to indicate that the root port can also cope, then assume the latter is lying.
Signed-off-by: David Woodhouse <david.woodho...@intel.com>
---
drivers/iommu/intel-iommu.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
index a6fd639..b5ab009 100644
--- a/drivers/iommu/intel-iommu.c
+++ b/drivers/iommu/intel-iommu.c
@@ -1447,9 +1447,14 @@ iommu_support_dev_iotlb (struct dmar_domain *domain,
struct intel_iommu *iommu,
if (!pci_find_ext_capability(pdev, PCI_EXT_CAP_ID_ATS))
return NULL;
- if (!dmar_find_matched_atsr_unit(pdev))
- return NULL;
-
+ if (!dmar_find_matched_atsr_unit(pdev)) {
+ if (intel_iommu_pasid28 && IS_GFX_DEVICE(pdev) &&
+ pdev->vendor == 0x8086) {
+ pr_warn("BIOS denies ATSR capability for %s; assuming
it lies\n",
+ dev_name(info->dev));
+ } else
+ return NULL;
+ }
return info;
}
--
2.4.3
--
David Woodhouse Open Source Technology Centre
david.woodho...@intel.com Intel Corporation
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