iommu/vt-d: Omit devTLB invalidation requests when TES=0

[ Upstream commit 0f5432a9b839847dcfe9fa369d72e3d646102ddf ]

The latest VT-d spec indicates that when remapping hardware is disabled
(TES=0 in Global Status Register), upstream ATS Invalidation Completion
requests are treated as UR (Unsupported Request).

Consequently, the spec recommends in section 4.3 Handling of Device-TLB
Invalidations that software refrain from submitting any Device-TLB
invalidation requests when address remapping hardware is disabled.

Verify address remapping hardware is enabled prior to submitting Device-
TLB invalidation requests.

Fixes: 792fb43ce2c9 ("iommu/vt-d: Enable Intel IOMMU scalable mode by default")
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20231114011036.70142-2-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/dmar.c b/drivers/iommu/intel/dmar.c
index f800989..418af1d 100644 (file)
--- a/drivers/iommu/intel/dmar.c
+++ b/drivers/iommu/intel/dmar.c
@@ -1495,6 +1495,15 @@ void qi_flush_dev_iotlb(struct intel_iommu *iommu, u16 sid, u16 pfsid,
 {
        struct qi_desc desc;
 
+       /*
+        * VT-d spec, section 4.3:
+        *
+        * Software is recommended to not submit any Device-TLB invalidation
+        * requests while address remapping hardware is disabled.
+        */
+       if (!(iommu->gcmd & DMA_GCMD_TE))
+               return;
+
        if (mask) {
                addr |= (1ULL << (VTD_PAGE_SHIFT + mask - 1)) - 1;
                desc.qw1 = QI_DEV_IOTLB_ADDR(addr) | QI_DEV_IOTLB_SIZE;
@@ -1560,6 +1569,15 @@ void qi_flush_dev_iotlb_pasid(struct intel_iommu *iommu, u16 sid, u16 pfsid,
        unsigned long mask = 1UL << (VTD_PAGE_SHIFT + size_order - 1);
        struct qi_desc desc = {.qw1 = 0, .qw2 = 0, .qw3 = 0};
 
+       /*
+        * VT-d spec, section 4.3:
+        *
+        * Software is recommended to not submit any Device-TLB invalidation
+        * requests while address remapping hardware is disabled.
+        */
+       if (!(iommu->gcmd & DMA_GCMD_TE))
+               return;
+
        desc.qw0 = QI_DEV_EIOTLB_PASID(pasid) | QI_DEV_EIOTLB_SID(sid) |
                QI_DEV_EIOTLB_QDEP(qdep) | QI_DEIOTLB_TYPE |
                QI_DEV_IOTLB_PFSID(pfsid);