[PATCH v2 07/12] iommu/vt-d: Acquiring lock in pasid manipulation helpers

[Lu Baolu <baolu.lu@linux.intel.com>]

The iommu->lock is used to protect the per-IOMMU pasid directory table
and pasid table. Move the spinlock acquisition/release into the helpers
to make the code self-contained. Again, the iommu->lock is never used
in interrupt contexts, hence there's no need to disable the interrupts
when holding the lock.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
---
 drivers/iommu/intel/iommu.c |   2 -
 drivers/iommu/intel/pasid.c | 108 +++++++++++++++++++-----------------
 drivers/iommu/intel/svm.c   |   5 +-
 3 files changed, 57 insertions(+), 58 deletions(-)

diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index 8fdaa01ef10d..12cd12fc86a4 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -2496,7 +2496,6 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
 		}
 
 		/* Setup the PASID entry for requests without PASID: */
-		spin_lock_irqsave(&iommu->lock, flags);
 		if (hw_pass_through && domain_type_is_si(domain))
 			ret = intel_pasid_setup_pass_through(iommu, domain,
 					dev, PASID_RID2PASID);
@@ -2506,7 +2505,6 @@ static int domain_add_dev_info(struct dmar_domain *domain, struct device *dev)
 		else
 			ret = intel_pasid_setup_second_level(iommu, domain,
 					dev, PASID_RID2PASID);
-		spin_unlock_irqrestore(&iommu->lock, flags);
 		if (ret) {
 			dev_err(dev, "Setup RID2PASID failed\n");
 			dmar_remove_one_dev_info(dev);
diff --git a/drivers/iommu/intel/pasid.c b/drivers/iommu/intel/pasid.c
index 641a4a6eb61e..3276895d7ba7 100644
--- a/drivers/iommu/intel/pasid.c
+++ b/drivers/iommu/intel/pasid.c
@@ -496,17 +496,17 @@ void intel_pasid_tear_down_entry(struct intel_iommu *iommu, struct device *dev,
 	struct pasid_entry *pte;
 	u16 did, pgtt;
 
+	spin_lock(&iommu->lock);
 	pte = intel_pasid_get_entry(dev, pasid);
-	if (WARN_ON(!pte))
-		return;
-
-	if (!pasid_pte_is_present(pte))
+	if (WARN_ON(!pte) || !pasid_pte_is_present(pte)) {
+		spin_unlock(&iommu->lock);
 		return;
+	}
 
 	did = pasid_get_domain_id(pte);
 	pgtt = pasid_pte_get_pgtt(pte);
-
 	intel_pasid_clear_entry(dev, pasid, fault_ignore);
+	spin_unlock(&iommu->lock);
 
 	if (!ecap_coherent(iommu->ecap))
 		clflush_cache_range(pte, sizeof(*pte));
@@ -542,21 +542,17 @@ static void pasid_flush_caches(struct intel_iommu *iommu,
 	}
 }
 
-static inline int pasid_enable_wpe(struct pasid_entry *pte)
+static struct pasid_entry *get_non_present_pasid_entry(struct device *dev,
+						       u32 pasid)
 {
-#ifdef CONFIG_X86
-	unsigned long cr0 = read_cr0();
+	struct pasid_entry *pte;
 
-	/* CR0.WP is normally set but just to be sure */
-	if (unlikely(!(cr0 & X86_CR0_WP))) {
-		pr_err_ratelimited("No CPU write protect!\n");
-		return -EINVAL;
-	}
-#endif
-	pasid_set_wpe(pte);
+	pte = intel_pasid_get_entry(dev, pasid);
+	if (!pte || pasid_pte_is_present(pte))
+		return NULL;
 
-	return 0;
-};
+	return pte;
+}
 
 /*
  * Set up the scalable mode pasid table entry for first only
@@ -574,39 +570,47 @@ int intel_pasid_setup_first_level(struct intel_iommu *iommu,
 		return -EINVAL;
 	}
 
-	pte = intel_pasid_get_entry(dev, pasid);
-	if (WARN_ON(!pte))
+	if ((flags & PASID_FLAG_SUPERVISOR_MODE)) {
+#ifdef CONFIG_X86
+		unsigned long cr0 = read_cr0();
+
+		/* CR0.WP is normally set but just to be sure */
+		if (unlikely(!(cr0 & X86_CR0_WP))) {
+			pr_err("No CPU write protect!\n");
+			return -EINVAL;
+		}
+#endif
+		if (!ecap_srs(iommu->ecap)) {
+			pr_err("No supervisor request support on %s\n",
+			       iommu->name);
+			return -EINVAL;
+		}
+	}
+
+	if ((flags & PASID_FLAG_FL5LP) && !cap_5lp_support(iommu->cap)) {
+		pr_err("No 5-level paging support for first-level on %s\n",
+		       iommu->name);
 		return -EINVAL;
+	}
 
-	/* Caller must ensure PASID entry is not in use. */
-	if (pasid_pte_is_present(pte))
+	spin_lock(&iommu->lock);
+	pte = get_non_present_pasid_entry(dev, pasid);
+	if (!pte) {
+		spin_unlock(&iommu->lock);
 		return -EBUSY;
+	}
 
 	pasid_clear_entry(pte);
 
 	/* Setup the first level page table pointer: */
 	pasid_set_flptr(pte, (u64)__pa(pgd));
 	if (flags & PASID_FLAG_SUPERVISOR_MODE) {
-		if (!ecap_srs(iommu->ecap)) {
-			pr_err("No supervisor request support on %s\n",
-			       iommu->name);
-			return -EINVAL;
-		}
 		pasid_set_sre(pte);
-		if (pasid_enable_wpe(pte))
-			return -EINVAL;
-
+		pasid_set_wpe(pte);
 	}
 
-	if (flags & PASID_FLAG_FL5LP) {
-		if (cap_5lp_support(iommu->cap)) {
-			pasid_set_flpm(pte, 1);
-		} else {
-			pr_err("No 5-level paging support for first-level\n");
-			pasid_clear_entry(pte);
-			return -EINVAL;
-		}
-	}
+	if (flags & PASID_FLAG_FL5LP)
+		pasid_set_flpm(pte, 1);
 
 	if (flags & PASID_FLAG_PAGE_SNOOP)
 		pasid_set_pgsnp(pte);
@@ -618,6 +622,8 @@ int intel_pasid_setup_first_level(struct intel_iommu *iommu,
 	/* Setup Present and PASID Granular Transfer Type: */
 	pasid_set_translation_type(pte, PASID_ENTRY_PGTT_FL_ONLY);
 	pasid_set_present(pte);
+	spin_unlock(&iommu->lock);
+
 	pasid_flush_caches(iommu, pte, pasid, did);
 
 	return 0;
@@ -675,15 +681,12 @@ int intel_pasid_setup_second_level(struct intel_iommu *iommu,
 	pgd_val = virt_to_phys(pgd);
 	did = domain->iommu_did[iommu->seq_id];
 
-	pte = intel_pasid_get_entry(dev, pasid);
+	spin_lock(&iommu->lock);
+	pte = get_non_present_pasid_entry(dev, pasid);
 	if (!pte) {
-		dev_err(dev, "Failed to get pasid entry of PASID %d\n", pasid);
-		return -ENODEV;
-	}
-
-	/* Caller must ensure PASID entry is not in use. */
-	if (pasid_pte_is_present(pte))
+		spin_unlock(&iommu->lock);
 		return -EBUSY;
+	}
 
 	pasid_clear_entry(pte);
 	pasid_set_domain_id(pte, did);
@@ -700,6 +703,8 @@ int intel_pasid_setup_second_level(struct intel_iommu *iommu,
 	if (pasid != PASID_RID2PASID)
 		pasid_set_sre(pte);
 	pasid_set_present(pte);
+	spin_unlock(&iommu->lock);
+
 	pasid_flush_caches(iommu, pte, pasid, did);
 
 	return 0;
@@ -715,15 +720,12 @@ int intel_pasid_setup_pass_through(struct intel_iommu *iommu,
 	u16 did = FLPT_DEFAULT_DID;
 	struct pasid_entry *pte;
 
-	pte = intel_pasid_get_entry(dev, pasid);
+	spin_lock(&iommu->lock);
+	pte = get_non_present_pasid_entry(dev, pasid);
 	if (!pte) {
-		dev_err(dev, "Failed to get pasid entry of PASID %d\n", pasid);
-		return -ENODEV;
-	}
-
-	/* Caller must ensure PASID entry is not in use. */
-	if (pasid_pte_is_present(pte))
+		spin_unlock(&iommu->lock);
 		return -EBUSY;
+	}
 
 	pasid_clear_entry(pte);
 	pasid_set_domain_id(pte, did);
@@ -738,6 +740,8 @@ int intel_pasid_setup_pass_through(struct intel_iommu *iommu,
 	 */
 	pasid_set_sre(pte);
 	pasid_set_present(pte);
+	spin_unlock(&iommu->lock);
+
 	pasid_flush_caches(iommu, pte, pasid, did);
 
 	return 0;
diff --git a/drivers/iommu/intel/svm.c b/drivers/iommu/intel/svm.c
index 580713aa9e07..64072e628bbd 100644
--- a/drivers/iommu/intel/svm.c
+++ b/drivers/iommu/intel/svm.c
@@ -328,9 +328,9 @@ static struct iommu_sva *intel_svm_bind_mm(struct intel_iommu *iommu,
 					   unsigned int flags)
 {
 	struct device_domain_info *info = dev_iommu_priv_get(dev);
-	unsigned long iflags, sflags;
 	struct intel_svm_dev *sdev;
 	struct intel_svm *svm;
+	unsigned long sflags;
 	int ret = 0;
 
 	svm = pasid_private_find(mm->pasid);
@@ -394,11 +394,8 @@ static struct iommu_sva *intel_svm_bind_mm(struct intel_iommu *iommu,
 	sflags = (flags & SVM_FLAG_SUPERVISOR_MODE) ?
 			PASID_FLAG_SUPERVISOR_MODE : 0;
 	sflags |= cpu_feature_enabled(X86_FEATURE_LA57) ? PASID_FLAG_FL5LP : 0;
-	spin_lock_irqsave(&iommu->lock, iflags);
 	ret = intel_pasid_setup_first_level(iommu, dev, mm->pgd, mm->pasid,
 					    FLPT_DEFAULT_DID, sflags);
-	spin_unlock_irqrestore(&iommu->lock, iflags);
-
 	if (ret)
 		goto free_sdev;
 
-- 
2.25.1