iommu: remove DOMAIN_ATTR_NESTING

Use an explicit enable_nesting method instead.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Will Deacon <will@kernel.org>
Acked-by: Li Yang <leoyang.li@nxp.com>
Link: https://lore.kernel.org/r/20210401155256.298656-17-hch@lst.de
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c

@@ -2555,15 +2555,6 @@ static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
 
 	switch (domain->type) {
-	case IOMMU_DOMAIN_UNMANAGED:
-		switch (attr) {
-		case DOMAIN_ATTR_NESTING:
-			*(int *)data = (smmu_domain->stage == ARM_SMMU_DOMAIN_NESTED);
-			return 0;
-		default:
-			return -ENODEV;
-		}
-		break;
 	case IOMMU_DOMAIN_DMA:
 		switch (attr) {
 		case DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE:
@@ -2587,23 +2578,6 @@ static int arm_smmu_domain_set_attr(struct iommu_domain *domain,
 	mutex_lock(&smmu_domain->init_mutex);
 
 	switch (domain->type) {
-	case IOMMU_DOMAIN_UNMANAGED:
-		switch (attr) {
-		case DOMAIN_ATTR_NESTING:
-			if (smmu_domain->smmu) {
-				ret = -EPERM;
-				goto out_unlock;
-			}
-
-			if (*(int *)data)
-				smmu_domain->stage = ARM_SMMU_DOMAIN_NESTED;
-			else
-				smmu_domain->stage = ARM_SMMU_DOMAIN_S1;
-			break;
-		default:
-			ret = -ENODEV;
-		}
-		break;
 	case IOMMU_DOMAIN_DMA:
 		switch(attr) {
 		case DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE:
@@ -2617,11 +2591,25 @@ static int arm_smmu_domain_set_attr(struct iommu_domain *domain,
 		ret = -EINVAL;
 	}
 
-out_unlock:
 	mutex_unlock(&smmu_domain->init_mutex);
 	return ret;
 }
 
+static int arm_smmu_enable_nesting(struct iommu_domain *domain)
+{
+	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+	int ret = 0;
+
+	mutex_lock(&smmu_domain->init_mutex);
+	if (smmu_domain->smmu)
+		ret = -EPERM;
+	else
+		smmu_domain->stage = ARM_SMMU_DOMAIN_NESTED;
+	mutex_unlock(&smmu_domain->init_mutex);
+
+	return ret;
+}
+
 static int arm_smmu_of_xlate(struct device *dev, struct of_phandle_args *args)
 {
 	return iommu_fwspec_add_ids(dev, args->args, 1);
@@ -2721,6 +2709,7 @@ static struct iommu_ops arm_smmu_ops = {
 	.device_group		= arm_smmu_device_group,
 	.domain_get_attr	= arm_smmu_domain_get_attr,
 	.domain_set_attr	= arm_smmu_domain_set_attr,
+	.enable_nesting		= arm_smmu_enable_nesting,
 	.of_xlate		= arm_smmu_of_xlate,
 	.get_resv_regions	= arm_smmu_get_resv_regions,
 	.put_resv_regions	= generic_iommu_put_resv_regions,

drivers/iommu/arm/arm-smmu/arm-smmu.c

@@ -1489,9 +1489,6 @@ static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
 	switch(domain->type) {
 	case IOMMU_DOMAIN_UNMANAGED:
 		switch (attr) {
-		case DOMAIN_ATTR_NESTING:
-			*(int *)data = (smmu_domain->stage == ARM_SMMU_DOMAIN_NESTED);
-			return 0;
 		case DOMAIN_ATTR_IO_PGTABLE_CFG: {
 			struct io_pgtable_domain_attr *pgtbl_cfg = data;
 			*pgtbl_cfg = smmu_domain->pgtbl_cfg;
@@ -1519,6 +1516,21 @@ static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
 	}
 }
 
+static int arm_smmu_enable_nesting(struct iommu_domain *domain)
+{
+	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+	int ret = 0;
+
+	mutex_lock(&smmu_domain->init_mutex);
+	if (smmu_domain->smmu)
+		ret = -EPERM;
+	else
+		smmu_domain->stage = ARM_SMMU_DOMAIN_NESTED;
+	mutex_unlock(&smmu_domain->init_mutex);
+
+	return ret;
+}
+
 static int arm_smmu_domain_set_attr(struct iommu_domain *domain,
 				    enum iommu_attr attr, void *data)
 {
@@ -1530,17 +1542,6 @@ static int arm_smmu_domain_set_attr(struct iommu_domain *domain,
 	switch(domain->type) {
 	case IOMMU_DOMAIN_UNMANAGED:
 		switch (attr) {
-		case DOMAIN_ATTR_NESTING:
-			if (smmu_domain->smmu) {
-				ret = -EPERM;
-				goto out_unlock;
-			}
-
-			if (*(int *)data)
-				smmu_domain->stage = ARM_SMMU_DOMAIN_NESTED;
-			else
-				smmu_domain->stage = ARM_SMMU_DOMAIN_S1;
-			break;
 		case DOMAIN_ATTR_IO_PGTABLE_CFG: {
 			struct io_pgtable_domain_attr *pgtbl_cfg = data;
 
@@ -1633,6 +1634,7 @@ static struct iommu_ops arm_smmu_ops = {
 	.device_group		= arm_smmu_device_group,
 	.domain_get_attr	= arm_smmu_domain_get_attr,
 	.domain_set_attr	= arm_smmu_domain_set_attr,
+	.enable_nesting		= arm_smmu_enable_nesting,
 	.of_xlate		= arm_smmu_of_xlate,
 	.get_resv_regions	= arm_smmu_get_resv_regions,
 	.put_resv_regions	= generic_iommu_put_resv_regions,

drivers/iommu/intel/iommu.c

@@ -5396,32 +5396,19 @@ static bool intel_iommu_is_attach_deferred(struct iommu_domain *domain,
 }
 
 static int
-intel_iommu_domain_set_attr(struct iommu_domain *domain,
+intel_iommu_enable_nesting(struct iommu_domain *domain)
-			    enum iommu_attr attr, void *data)
 {
 	struct dmar_domain *dmar_domain = to_dmar_domain(domain);
 	unsigned long flags;
-	int ret = 0;
+	int ret = -ENODEV;
 
-	if (domain->type != IOMMU_DOMAIN_UNMANAGED)
-		return -EINVAL;
-
-	switch (attr) {
-	case DOMAIN_ATTR_NESTING:
 	spin_lock_irqsave(&device_domain_lock, flags);
-		if (nested_mode_support() &&
+	if (nested_mode_support() && list_empty(&dmar_domain->devices)) {
-		    list_empty(&dmar_domain->devices)) {
 		dmar_domain->flags |= DOMAIN_FLAG_NESTING_MODE;
 		dmar_domain->flags &= ~DOMAIN_FLAG_USE_FIRST_LEVEL;
-		} else {
+		ret = 0;
-			ret = -ENODEV;
 	}
 	spin_unlock_irqrestore(&device_domain_lock, flags);
-		break;
-	default:
-		ret = -EINVAL;
-		break;
-	}
 
 	return ret;
 }
@@ -5550,7 +5537,7 @@ const struct iommu_ops intel_iommu_ops = {
 	.domain_alloc		= intel_iommu_domain_alloc,
 	.domain_free		= intel_iommu_domain_free,
 	.domain_get_attr        = intel_iommu_domain_get_attr,
-	.domain_set_attr	= intel_iommu_domain_set_attr,
+	.enable_nesting		= intel_iommu_enable_nesting,
 	.attach_dev		= intel_iommu_attach_device,
 	.detach_dev		= intel_iommu_detach_device,
 	.aux_attach_dev		= intel_iommu_aux_attach_device,

drivers/iommu/iommu.c

@@ -2690,6 +2690,16 @@ int iommu_domain_set_attr(struct iommu_domain *domain,
 }
 EXPORT_SYMBOL_GPL(iommu_domain_set_attr);
 
+int iommu_enable_nesting(struct iommu_domain *domain)
+{
+	if (domain->type != IOMMU_DOMAIN_UNMANAGED)
+		return -EINVAL;
+	if (!domain->ops->enable_nesting)
+		return -EINVAL;
+	return domain->ops->enable_nesting(domain);
+}
+EXPORT_SYMBOL_GPL(iommu_enable_nesting);
+
 void iommu_get_resv_regions(struct device *dev, struct list_head *list)
 {
 	const struct iommu_ops *ops = dev->bus->iommu_ops;

drivers/vfio/vfio_iommu_type1.c

@@ -2320,10 +2320,7 @@ static int vfio_iommu_type1_attach_group(void *iommu_data,
 	}
 
 	if (iommu->nesting) {
-		int attr = 1;
+		ret = iommu_enable_nesting(domain->domain);
-
-		ret = iommu_domain_set_attr(domain->domain, DOMAIN_ATTR_NESTING,
-					    &attr);
 		if (ret)
 			goto out_domain;
 	}

include/linux/iommu.h

@@ -107,7 +107,6 @@ enum iommu_cap {
  */
 
 enum iommu_attr {
-	DOMAIN_ATTR_NESTING,	/* two stages of translation */
 	DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE,
 	DOMAIN_ATTR_IO_PGTABLE_CFG,
 	DOMAIN_ATTR_MAX,
@@ -210,6 +209,7 @@ struct iommu_iotlb_gather {
  * @device_group: find iommu group for a particular device
  * @domain_get_attr: Query domain attributes
  * @domain_set_attr: Change domain attributes
+ * @enable_nesting: Enable nesting
  * @get_resv_regions: Request list of reserved regions for a device
  * @put_resv_regions: Free list of reserved regions for a device
  * @apply_resv_region: Temporary helper call-back for iova reserved ranges
@@ -262,6 +262,7 @@ struct iommu_ops {
 			       enum iommu_attr attr, void *data);
 	int (*domain_set_attr)(struct iommu_domain *domain,
 			       enum iommu_attr attr, void *data);
+	int (*enable_nesting)(struct iommu_domain *domain);
 
 	/* Request/Free a list of reserved regions for a device */
 	void (*get_resv_regions)(struct device *dev, struct list_head *list);
@@ -511,6 +512,7 @@ extern int iommu_domain_get_attr(struct iommu_domain *domain, enum iommu_attr,
 				 void *data);
 extern int iommu_domain_set_attr(struct iommu_domain *domain, enum iommu_attr,
 				 void *data);
+int iommu_enable_nesting(struct iommu_domain *domain);
 
 extern int report_iommu_fault(struct iommu_domain *domain, struct device *dev,
 			      unsigned long iova, int flags);