iommu/vt-d: Use user privilege for RID2PASID translation

[ Upstream commit 54c80d90 ]

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: b802d070

 ("iommu/vt-d: Use iova over first level")
Suggested-by: Jacob Pan <jacob.jun.pan@linux.intel.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Link: https://lore.kernel.org/r/20210512064426.3440915-1-baolu.lu@linux.intel.com
Link: https://lore.kernel.org/r/20210519015027.108468-3-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>