[PATCH 5.12 265/296] iommu/vt-d: Use user privilege for RID2PASID translation

[Greg Kroah-Hartman]

From: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>

[ Upstream commit 54c80d907400189b09548039be8f3b6e297e8ae3 ]

When first-level page tables are used for IOVA translation, we use user
privilege by setting U/S bit in the page table entry. This is to make it
consistent with the second level translation, where the U/S enforcement
is not available. Clear the SRE (Supervisor Request Enable) field in the
pasid table entry of RID2PASID so that requests requesting the supervisor
privilege are blocked and treated as DMA remapping faults.

Fixes: b802d070a52a1 ("iommu/vt-d: Use iova over first level")
Suggested-by: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20210512064426.3440915-1-baolu.lu@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20210519015027.108468-3-baolu.lu@xxxxxxxxxxxxxxx
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/iommu/intel/iommu.c | 7 +++++--
 drivers/iommu/intel/pasid.c | 3 ++-
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 2569585ffcd4..56930e0b8f59 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -2525,9 +2525,9 @@ static int domain_setup_first_level(struct intel_iommu *iommu,
 				    struct device *dev,
 				    u32 pasid)
 {
-	int flags = PASID_FLAG_SUPERVISOR_MODE;
 	struct dma_pte *pgd = domain->pgd;
 	int agaw, level;
+	int flags = 0;
 
 	/*
 	 * Skip top levels of page tables for iommu which has
@@ -2543,7 +2543,10 @@ static int domain_setup_first_level(struct intel_iommu *iommu,
 	if (level != 4 && level != 5)
 		return -EINVAL;
 
-	flags |= (level == 5) ? PASID_FLAG_FL5LP : 0;
+	if (pasid != PASID_RID2PASID)
+		flags |= PASID_FLAG_SUPERVISOR_MODE;
+	if (level == 5)
+		flags |= PASID_FLAG_FL5LP;
 
 	if (domain->domain.type == IOMMU_DOMAIN_UNMANAGED)
 		flags |= PASID_FLAG_PAGE_SNOOP;
diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index 5093d317ff1a..77fbe9908abd 100644
--- a/drivers/iommu/intel/pasid.c
+++ b/drivers/iommu/intel/pasid.c
@@ -663,7 +663,8 @@ int intel_pasid_setup_second_level(struct intel_iommu *iommu,
 	 * Since it is a second level only translation setup, we should
 	 * set SRE bit as well (addresses are expected to be GPAs).
 	 */
-	pasid_set_sre(pte);
+	if (pasid != PASID_RID2PASID)
+		pasid_set_sre(pte);
 	pasid_set_present(pte);
 	pasid_flush_caches(iommu, pte, pasid, did);
 
-- 
2.30.2