Messages in this thread Patch in this message | | | Date | Thu, 3 Aug 2023 00:32:35 +0800 | Subject | [PATCH v4 7/8] iommu/arm-smmu-v3: Skip cd sync if CD table isn't active | From | Michael Shavit <> |
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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.
Signed-off-by: Michael Shavit <mshavit@google.com> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com> ---
(no changes since v3)
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 | 8 +++++++- drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 2 ++ 2 files changed, 9 insertions(+), 1 deletion(-)
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 e2c33024ad85..00b602ae9636 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; @@ -1091,7 +1094,7 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_master *master, int ssid, cdptr[3] = cpu_to_le64(cd->mair); /* - * STE is live, and the SMMU might read dwords of this CD in any + * STE may be live, and the SMMU might read dwords of this CD in any * order. Ensure that it observes valid values before reading * V=1. */ @@ -1360,6 +1363,9 @@ static void arm_smmu_write_strtab_ent(struct arm_smmu_master *master, u32 sid, cd_table->l1_desc ? STRTAB_STE_0_S1FMT_64K_L2 : STRTAB_STE_0_S1FMT_LINEAR); + 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 1f3b37025777..e76452e735a0 100644 --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h @@ -599,6 +599,8 @@ struct arm_smmu_ctx_desc_cfg { u8 max_cds_bits; /* 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 { -- 2.41.0.585.gd2178a4bd4-goog
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