[PATCH v6 09/10] iommu/arm-smmu-v3: Skip cd sync if CD table isn't active
From: Michael Shavit <hidden>
Date: 2023-08-16 13:21:10
Also in:
linux-iommu, lkml
Subsystem:
arm smmu drivers, iommu subsystem, the rest · Maintainers:
Will Deacon, Joerg Roedel, Linus Torvalds
This commit explicitly keeps track of whether a CD table is installed in an STE so that arm_smmu_sync_cd can skip the sync when unnecessary. This was previously achieved through the domain->devices list, but we are moving to a model where arm_smmu_sync_cd directly operates on a master and the master's CD table instead of a domain. Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> Reviewed-by: Nicolin Chen <redacted> Signed-off-by: Michael Shavit <redacted> --- Happy to drop this commit if we don't think it's useful. (no changes since v5) Changes in v5: - Fix an issue where cd_table.installed wasn't correctly updated. Changes in v3: - Flip the cd_table.installed bit back off when table is detached - re-order the commit later in the series since flipping the installed bit to off isn't obvious when the cd_table is still shared by multiple masters. Changes in v2: - Store field as a bit instead of a bool. Fix comment about STE being live before the sync in write_ctx_desc(). drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 7 +++++++ drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 2 ++ 2 files changed, 9 insertions(+)
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 3c8bfeca89d5c..104b8d6ea5972 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c@@ -985,6 +985,9 @@ static void arm_smmu_sync_cd(struct arm_smmu_master *master, }, }; + if (!master->cd_table.installed) + return; + cmds.num = 0; for (i = 0; i < master->num_streams; i++) { cmd.cfgi.sid = master->streams[i].id;
@@ -1335,6 +1338,7 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid, */ if (smmu) arm_smmu_sync_ste_for_sid(smmu, sid); + master->cd_table.installed = false; return; }
@@ -1358,6 +1362,9 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid, FIELD_PREP(STRTAB_STE_0_CFG, STRTAB_STE_0_CFG_S1_TRANS) | FIELD_PREP(STRTAB_STE_0_S1CDMAX, cd_table->s1cdmax) | FIELD_PREP(STRTAB_STE_0_S1FMT, cd_table->s1fmt); + cd_table->installed = true; + } else { + master->cd_table.installed = false; } if (s2_cfg) {
diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
index 2f4b832e0deb4..b7a91c8e9b523 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h@@ -600,6 +600,8 @@ struct arm_smmu_ctx_desc_cfg { u8 s1cdmax; /* Whether CD entries in this table have the stall bit set. */ u8 stall_enabled:1; + /* Whether this CD table is installed in any STE */ + u8 installed:1; }; struct arm_smmu_s2_cfg {
--
2.41.0.694.ge786442a9b-goog
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