This is a note to let you know that I've just added the patch titled
iommu/arm-smmu-v3: Set TTL invalidation hint better
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
iommu-arm-smmu-v3-set-ttl-invalidation-hint-better.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 0b631a6adf27bbb29731ad408df5b79ee534d030
Author: Robin Murphy <robin.murphy@xxxxxxx>
Date: Thu Jun 1 17:43:33 2023 +0100
iommu/arm-smmu-v3: Set TTL invalidation hint better
[ Upstream commit 6833b8f2e19945a41e4d5efd8c6d9f4cae9a5b7d ]
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.
Signed-off-by: Robin Murphy <robin.murphy@xxxxxxx>
Link: https://lore.kernel.org/r/b409d9a17c52dc0db51faee91d92737bb7975f5b.1685637456.git.robin.murphy@xxxxxxx
Signed-off-by: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
index 340ef116d574a..67845f8e1df9f 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -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;
}
