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From:   Tina Zhang <tina.zhang@intel.com>
To:     Jason Gunthorpe <jgg@ziepe.ca>, Kevin Tian <kevin.tian@intel.com>,
        Lu Baolu <baolu.lu@linux.intel.com>
Cc:     Michael Shavit <mshavit@google.com>,
        Vasant Hegde <vasant.hegde@amd.com>, iommu@lists.linux.dev,
        linux-kernel@vger.kernel.org, Tina Zhang <tina.zhang@intel.com>
Subject: [PATCH v5 3/6] iommu: Introduce mm_get_pasid() helper function
Date:   Mon, 25 Sep 2023 10:38:10 +0800
Message-Id: <20230925023813.575016-4-tina.zhang@intel.com>
In-Reply-To: <20230925023813.575016-1-tina.zhang@intel.com>
References: <20230925023813.575016-1-tina.zhang@intel.com>
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Use the helper function mm_get_pasid() to get a mm assigned pasid
value. The motivation is to replace mm->pasid with an iommu private
data structure that is introduced in a later patch.

The mm_get_pasid() is intended for generic usage of mm's pasid.
Using mm_get_pasid() for shared virtual addressing (SVA) with enqcmd
usage is discouraged. Instead, one should consider using
mm_get_enqcmd_pasid().

Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Tina Zhang <tina.zhang@intel.com>
---

Change in v5:
- Update commit message.

Change in v4:
- Rebase to v6.6-rc1.

Changes in v2:
- Update commit message.
- Let mm_get_enqcmd_pasid() call mm_get_pasid() to get pasid.

 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c | 12 ++++++------
 drivers/iommu/iommu-sva.c                       | 12 ++++++------
 include/linux/iommu.h                           | 10 +++++++++-
 3 files changed, 21 insertions(+), 13 deletions(-)

diff --git a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
index 4d83edc2be99..dbb3af323ede 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3-sva.c
@@ -215,7 +215,7 @@ static void arm_smmu_mm_arch_invalidate_secondary_tlbs(struct mmu_notifier *mn,
 						    smmu_domain);
 	}
 
-	arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, start, size);
+	arm_smmu_atc_inv_domain(smmu_domain, mm_get_pasid(mm), start, size);
 }
 
 static void arm_smmu_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
@@ -233,10 +233,10 @@ static void arm_smmu_mm_release(struct mmu_notifier *mn, struct mm_struct *mm)
 	 * DMA may still be running. Keep the cd valid to avoid C_BAD_CD events,
 	 * but disable translation.
 	 */
-	arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, &quiet_cd);
+	arm_smmu_write_ctx_desc(smmu_domain, mm_get_pasid(mm), &quiet_cd);
 
 	arm_smmu_tlb_inv_asid(smmu_domain->smmu, smmu_mn->cd->asid);
-	arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, 0, 0);
+	arm_smmu_atc_inv_domain(smmu_domain, mm_get_pasid(mm), 0, 0);
 
 	smmu_mn->cleared = true;
 	mutex_unlock(&sva_lock);
@@ -290,7 +290,7 @@ arm_smmu_mmu_notifier_get(struct arm_smmu_domain *smmu_domain,
 		goto err_free_cd;
 	}
 
-	ret = arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, cd);
+	ret = arm_smmu_write_ctx_desc(smmu_domain, mm_get_pasid(mm), cd);
 	if (ret)
 		goto err_put_notifier;
 
@@ -315,7 +315,7 @@ static void arm_smmu_mmu_notifier_put(struct arm_smmu_mmu_notifier *smmu_mn)
 		return;
 
 	list_del(&smmu_mn->list);
-	arm_smmu_write_ctx_desc(smmu_domain, mm->pasid, NULL);
+	arm_smmu_write_ctx_desc(smmu_domain, mm_get_pasid(mm), NULL);
 
 	/*
 	 * If we went through clear(), we've already invalidated, and no
@@ -323,7 +323,7 @@ static void arm_smmu_mmu_notifier_put(struct arm_smmu_mmu_notifier *smmu_mn)
 	 */
 	if (!smmu_mn->cleared) {
 		arm_smmu_tlb_inv_asid(smmu_domain->smmu, cd->asid);
-		arm_smmu_atc_inv_domain(smmu_domain, mm->pasid, 0, 0);
+		arm_smmu_atc_inv_domain(smmu_domain, mm_get_pasid(mm), 0, 0);
 	}
 
 	/* Frees smmu_mn */
diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c
index b78671a8a914..0f956ecd0c9b 100644
--- a/drivers/iommu/iommu-sva.c
+++ b/drivers/iommu/iommu-sva.c
@@ -23,7 +23,7 @@ static int iommu_sva_alloc_pasid(struct mm_struct *mm, struct device *dev)
 	mutex_lock(&iommu_sva_lock);
 	/* Is a PASID already associated with this mm? */
 	if (mm_valid_pasid(mm)) {
-		if (mm->pasid >= dev->iommu->max_pasids)
+		if (mm_get_pasid(mm) >= dev->iommu->max_pasids)
 			ret = -EOVERFLOW;
 		goto out;
 	}
@@ -73,7 +73,7 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm
 
 	mutex_lock(&iommu_sva_lock);
 	/* Search for an existing domain. */
-	domain = iommu_get_domain_for_dev_pasid(dev, mm->pasid,
+	domain = iommu_get_domain_for_dev_pasid(dev, mm_get_pasid(mm),
 						IOMMU_DOMAIN_SVA);
 	if (IS_ERR(domain)) {
 		ret = PTR_ERR(domain);
@@ -92,7 +92,7 @@ struct iommu_sva *iommu_sva_bind_device(struct device *dev, struct mm_struct *mm
 		goto out_unlock;
 	}
 
-	ret = iommu_attach_device_pasid(domain, dev, mm->pasid);
+	ret = iommu_attach_device_pasid(domain, dev, mm_get_pasid(mm));
 	if (ret)
 		goto out_free_domain;
 	domain->users = 1;
@@ -124,7 +124,7 @@ EXPORT_SYMBOL_GPL(iommu_sva_bind_device);
 void iommu_sva_unbind_device(struct iommu_sva *handle)
 {
 	struct iommu_domain *domain = handle->domain;
-	ioasid_t pasid = domain->mm->pasid;
+	ioasid_t pasid = mm_get_pasid(domain->mm);
 	struct device *dev = handle->dev;
 
 	mutex_lock(&iommu_sva_lock);
@@ -141,7 +141,7 @@ u32 iommu_sva_get_pasid(struct iommu_sva *handle)
 {
 	struct iommu_domain *domain = handle->domain;
 
-	return domain->mm->pasid;
+	return mm_get_pasid(domain->mm);
 }
 EXPORT_SYMBOL_GPL(iommu_sva_get_pasid);
 
@@ -208,5 +208,5 @@ void mm_pasid_drop(struct mm_struct *mm)
 	if (likely(!mm_valid_pasid(mm)))
 		return;
 
-	iommu_free_global_pasid(mm->pasid);
+	iommu_free_global_pasid(mm_get_pasid(mm));
 }
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index a4eab6697fe1..db2510da28c1 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -1189,10 +1189,14 @@ static inline bool mm_valid_pasid(struct mm_struct *mm)
 {
 	return mm->pasid != IOMMU_PASID_INVALID;
 }
-static inline u32 mm_get_enqcmd_pasid(struct mm_struct *mm)
+static inline u32 mm_get_pasid(struct mm_struct *mm)
 {
 	return mm->pasid;
 }
+static inline u32 mm_get_enqcmd_pasid(struct mm_struct *mm)
+{
+	return mm_get_pasid(mm);
+}
 void mm_pasid_drop(struct mm_struct *mm);
 struct iommu_sva *iommu_sva_bind_device(struct device *dev,
 					struct mm_struct *mm);
@@ -1215,6 +1219,10 @@ static inline u32 iommu_sva_get_pasid(struct iommu_sva *handle)
 }
 static inline void mm_pasid_init(struct mm_struct *mm) {}
 static inline bool mm_valid_pasid(struct mm_struct *mm) { return false; }
+static inline u32 mm_get_pasid(struct mm_struct *mm)
+{
+	return IOMMU_PASID_INVALID;
+}
 static inline u32 mm_get_enqcmd_pasid(struct mm_struct *mm)
 {
 	return IOMMU_PASID_INVALID;
-- 
2.34.1