iommu/vt-d: Disable PCI ATS in legacy passthrough mode

[ Upstream commit da37dddcf4caf015c400a930301d2ee27a7a15fb ]

When IOMMU hardware operates in legacy mode, the TT field of the context
entry determines the translation type, with three supported types (Section
9.3 Context Entry):

- DMA translation without device TLB support
- DMA translation with device TLB support
- Passthrough mode with translated and translation requests blocked

Device TLB support is absent when hardware is configured in passthrough
mode.

Disable the PCI ATS feature when IOMMU is configured for passthrough
translation type in legacy (non-scalable) mode.

Fixes: 0faa19a1515f ("iommu/vt-d: Decouple PASID & PRI enabling from SVA")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20231114011036.70142-3-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index de76272d0fb0206f60df781a4eaaa2a9f33cc753..807abf4707be73aca634eaee16d4d3684dd8b362 100644 (file)
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -2517,7 +2517,8 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
                return ret;
        }
 
-       iommu_enable_pci_caps(info);
+       if (sm_supported(info->iommu) || !domain_type_is_si(info->domain))
+               iommu_enable_pci_caps(info);
 
        return 0;
 }