iommu/vt-d: Enable ATS only if the device uses page aligned address.

Kuppuswamy Sathyanarayanan · joergroedel · commit 61363c1474b1 · 2019-02-26T11:08:07.000+01:00
As per Intel vt-d specification, Rev 3.0 (section 7.5.1.1, title "Page
Request Descriptor"), Intel IOMMU page request descriptor only uses
bits[63:12] of the page address. Hence Intel IOMMU driver would only
permit devices that advertise they would only send Page Aligned Requests
to participate in ATS service.

Cc: Ashok Raj &lt;ashok.raj@intel.com&gt;
Cc: Jacob Pan &lt;jacob.jun.pan@linux.intel.com&gt;
Cc: Keith Busch &lt;keith.busch@intel.com&gt;
Suggested-by: Ashok Raj &lt;ashok.raj@intel.com&gt;
Signed-off-by: Kuppuswamy Sathyanarayanan &lt;sathyanarayanan.kuppuswamy@linux.intel.com&gt;
Signed-off-by: Joerg Roedel &lt;jroedel@suse.de&gt;
diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c
@@ -1408,6 +1408,7 @@ static void iommu_enable_dev_iotlb(struct device_domain_info *info)
 		info->pri_enabled = 1;
 #endif
 	if (!pdev->untrusted && info->ats_supported &&
+	    pci_ats_page_aligned(pdev) &&
 	    !pci_enable_ats(pdev, VTD_PAGE_SHIFT)) {
 		info->ats_enabled = 1;
 		domain_update_iotlb(info->domain);
