Commit 184bee38 authored by Lu Baolu's avatar Lu Baolu Committed by Joerg Roedel
Browse files

iommu/vt-d: Require DMA domain if hardware not support passthrough 



The iommu core defines the def_domain_type callback to query the iommu
driver about hardware capability and quirks. The iommu driver should
declare IOMMU_DOMAIN_DMA requirement for hardware lacking pass-through
capability.

Earlier VT-d hardware implementations did not support pass-through
translation mode. The iommu driver relied on a paging domain with all
physical system memory addresses identically mapped to the same IOVA
to simulate pass-through translation before the def_domain_type was
introduced and it has been kept until now. It's time to adjust it now
to make the Intel iommu driver follow the def_domain_type semantics.

Signed-off-by: default avatarLu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: default avatarJason Gunthorpe <jgg@nvidia.com>
Reviewed-by: default avatarKevin Tian <kevin.tian@intel.com>
Reviewed-by: default avatarJerry Snitselaar <jsnitsel@redhat.com>
Link: https://lore.kernel.org/r/20240809055431.36513-2-baolu.lu@linux.intel.com


Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
parent 7c626ce4

drivers/iommu/intel/iommu.c

+10 −0
Original line number Diff line number Diff line
@@ -2149,6 +2149,16 @@ static bool device_rmrr_is_relaxable(struct device *dev) 


static int device_def_domain_type(struct device *dev)

{

	struct device_domain_info *info = dev_iommu_priv_get(dev);

	struct intel_iommu *iommu = info->iommu;



	/*

	 * Hardware does not support the passthrough translation mode.

	 * Always use a dynamaic mapping domain.

	 */

	if (!ecap_pass_through(iommu->ecap))

		return IOMMU_DOMAIN_DMA;



	if (dev_is_pci(dev)) {

		struct pci_dev *pdev = to_pci_dev(dev);