linux-kernel - [PATCH v6 04/10] iommu/arm-smmu-v3: move stall

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Message-ID: <20230816211849.v6.4.I5aa89c849228794a64146cfe86df21fb71629384@changeid>
Date:   Wed, 16 Aug 2023 21:18:44 +0800
From:   Michael Shavit <mshavit@...gle.com>
To:     iommu@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org,
        linux-kernel@...r.kernel.org
Cc:     robin.murphy@....com, will@...nel.org, jean-philippe@...aro.org,
        jgg@...dia.com, nicolinc@...dia.com,
        Michael Shavit <mshavit@...gle.com>
Subject: [PATCH v6 04/10] iommu/arm-smmu-v3: move stall_enabled to the cd table

A domain can be attached to multiple masters with different
master->stall_enabled values. The stall bit of a CD entry should follow
master->stall_enabled and has an inverse relationship with the
STE.S1STALLD bit.

The stall_enabled bit does not depend on any property of the domain, so
move it out of the arm_smmu_domain struct.  Move it to the CD table
struct so that it can fully describe how CD entries should be written to
it.

Reviewed-by: Jason Gunthorpe <jgg@...dia.com>
Reviewed-by: Nicolin Chen <nicolinc@...dia.com>
Signed-off-by: Michael Shavit <mshavit@...gle.com>
---

(no changes since v5)

Changes in v5:
- Reword commit

Changes in v2:
- Use a bitfield instead of a bool for stall_enabled

 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 8 ++++----
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h | 3 ++-
 2 files changed, 6 insertions(+), 5 deletions(-)

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 5bb13fadb41ad..44df7c0926802 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -1114,7 +1114,7 @@ int arm_smmu_write_ctx_desc(struct arm_smmu_domain *smmu_domain, int ssid,
 			FIELD_PREP(CTXDESC_CD_0_ASID, cd->asid) |
 			CTXDESC_CD_0_V;
 
-		if (smmu_domain->stall_enabled)
+		if (smmu_domain->cd_table.stall_enabled)
 			val |= CTXDESC_CD_0_S;
 	}
 
@@ -1141,6 +1141,7 @@ static int arm_smmu_alloc_cd_tables(struct arm_smmu_domain *smmu_domain,
 	struct arm_smmu_device *smmu = smmu_domain->smmu;
 	struct arm_smmu_ctx_desc_cfg *cdcfg = &smmu_domain->cd_table;
 
+	cdcfg->stall_enabled = master->stall_enabled;
 	cdcfg->s1cdmax = master->ssid_bits;
 	max_contexts = 1 << cdcfg->s1cdmax;
 
@@ -2119,8 +2120,6 @@ static int arm_smmu_domain_finalise_s1(struct arm_smmu_domain *smmu_domain,
 	if (ret)
 		goto out_unlock;
 
-	smmu_domain->stall_enabled = master->stall_enabled;
-
 	ret = arm_smmu_alloc_cd_tables(smmu_domain, master);
 	if (ret)
 		goto out_free_asid;
@@ -2459,7 +2458,8 @@ static int arm_smmu_attach_dev(struct iommu_domain *domain, struct device *dev)
 		ret = -EINVAL;
 		goto out_unlock;
 	} else if (smmu_domain->stage == ARM_SMMU_DOMAIN_S1 &&
-		   smmu_domain->stall_enabled != master->stall_enabled) {
+		   smmu_domain->cd_table.stall_enabled !=
+			   master->stall_enabled) {
 		ret = -EINVAL;
 		goto out_unlock;
 	}
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 5f0e7468db5f3..007758df57610 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.h
@@ -598,6 +598,8 @@ struct arm_smmu_ctx_desc_cfg {
 	u8				s1fmt;
 	/* log2 of the maximum number of CDs supported by this table */
 	u8				s1cdmax;
+	/* Whether CD entries in this table have the stall bit set. */
+	u8				stall_enabled:1;
 };
 
 struct arm_smmu_s2_cfg {
@@ -715,7 +717,6 @@ struct arm_smmu_domain {
 	struct mutex			init_mutex; /* Protects smmu pointer */
 
 	struct io_pgtable_ops		*pgtbl_ops;
-	bool				stall_enabled;
 	atomic_t			nr_ats_masters;
 
 	enum arm_smmu_domain_stage	stage;
-- 
2.41.0.694.ge786442a9b-goog