ARM SMMUv3 errata fixes

An errata fix, and a fix for it

Robin Murphy (2):
iommu/arm-smmu-v3: Set TTL invalidation hint better iommu/arm-smmu-v3: Avoid constructing invalid range commands

 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

2.34.1

From: Robin Murphy <[email protected]>

commit 6833b8f2e19945a41e4d5efd8c6d9f4cae9a5b7d upstream

When io-pgtable unmaps a whole table, rather than waste time walking it to find the leaf entries to invalidate exactly, it simply expects .tlb_flush_walk with nominal last-level granularity to invalidate any leaf entries at higher intermediate levels as well. This works fine with page-based invalidation, but with range commands we need to be careful with the TTL hint - unconditionally setting it based on the given level 3 granule means that an invalidation for a level 1 table would strictly not be required to affect level 2 block entries. It's easy to comply with the expected behaviour by simply not setting the TTL hint for non-leaf invalidations, so let's do that.

---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

index 340ef116d574..67845f8e1df9 100644
@@ -1884,8 +1884,13 @@ static void __arm_smmu_tlb_inv_range(struct arm_smmu_cmdq_ent *cmd,
 		/* Convert page size of 12,14,16 (log2) to 1,2,3 */
 		cmd->tlbi.tg = (tg - 10) / 2;
 
-		/* Determine what level the granule is at */
-		cmd->tlbi.ttl = 4 - ((ilog2(granule) - 3) / (tg - 3));
+		/*
+		 * Determine what level the granule is at. For non-leaf, io-pgtable
+		 * assumes .tlb_flush_walk can invalidate multiple levels at once,
+		 * so ignore the nominal last-level granule and leave TTL=0.
+		 */
+		if (cmd->tlbi.leaf)
+			cmd->tlbi.ttl = 4 - ((ilog2(granule) - 3) / (tg - 3));
 
 		num_pages = size >> tg;
 	}

2.34.1

From: Robin Murphy <[email protected]>

commit eb6c97647be227822c7ce23655482b05e348fba5 upstream

Although io-pgtable's non-leaf invalidations are always for full tables, I missed that SVA also uses non-leaf invalidations, while being at the mercy of whatever range the MMU notifier throws at it. This means it definitely wants the previous TTL fix as well, since it also doesn't know exactly which leaf level(s) may need invalidating, but it can also give us less-aligned ranges wherein certain corners may lead to building an invalid command where TTL, Num and Scale are all 0. It should be fine to handle this by over-invalidating an extra page, since falling back to a non-range command opens up a whole can of errata-flavoured worms.

---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

index 67845f8e1df9..761cb657f256 100644
@@ -1881,18 +1881,23 @@ static void __arm_smmu_tlb_inv_range(struct arm_smmu_cmdq_ent *cmd,
 		/* Get the leaf page size */
 		tg = __ffs(smmu_domain->domain.pgsize_bitmap);
 
+		num_pages = size >> tg;
+
 		/* Convert page size of 12,14,16 (log2) to 1,2,3 */
 		cmd->tlbi.tg = (tg - 10) / 2;
 
 		/*
-		 * Determine what level the granule is at. For non-leaf, io-pgtable
-		 * assumes .tlb_flush_walk can invalidate multiple levels at once,
-		 * so ignore the nominal last-level granule and leave TTL=0.
+		 * Determine what level the granule is at. For non-leaf, both
+		 * io-pgtable and SVA pass a nominal last-level granule because
+		 * they don't know what level(s) actually apply, so ignore that
+		 * and leave TTL=0. However for various errata reasons we still
+		 * want to use a range command, so avoid the SVA corner case
+		 * where both scale and num could be 0 as well.
 		 */
 		if (cmd->tlbi.leaf)
 			cmd->tlbi.ttl = 4 - ((ilog2(granule) - 3) / (tg - 3));
-
-		num_pages = size >> tg;
+		else if ((num_pages & CMDQ_TLBI_RANGE_NUM_MAX) == 1)
+			num_pages++;
 	}
 
 	cmds.num = 0;

2.34.1