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Message-ID: <20230803003234.v4.7.Idedc0f496231e2faab3df057219c5e2d937bbfe4@changeid>
Date: Thu, 3 Aug 2023 00:32:35 +0800
From: Michael Shavit <mshavit@...gle.com>
To: iommu@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org,
linux-kernel@...r.kernel.org
Cc: will@...nel.org, robin.murphy@....com, nicolinc@...dia.com,
jgg@...dia.com, jean-philippe@...aro.org,
Michael Shavit <mshavit@...gle.com>
Subject: [PATCH v4 7/8] iommu/arm-smmu-v3: Skip cd sync if CD table isn't active
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@...gle.com>
Reviewed-by: Jason Gunthorpe <jgg@...dia.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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