diff mbox series

[15/17] iommu: remove DOMAIN_ATTR_NESTING

Message ID 20210301084257.945454-16-hch@lst.de (mailing list archive)
State New, archived
Headers show
Series [01/17] iommu: remove the unused domain_window_disable method | expand

Commit Message

Christoph Hellwig March 1, 2021, 8:42 a.m. UTC
Signed-off-by: Christoph Hellwig <hch@lst.de>
---
 drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 40 ++++++---------------
 drivers/iommu/arm/arm-smmu/arm-smmu.c       | 30 ++++++++++------
 drivers/iommu/intel/iommu.c                 | 28 +++++----------
 drivers/iommu/iommu.c                       |  8 +++++
 drivers/vfio/vfio_iommu_type1.c             |  5 +--
 include/linux/iommu.h                       |  4 ++-
 6 files changed, 50 insertions(+), 65 deletions(-)

Comments

Auger Eric March 14, 2021, 10:44 a.m. UTC | #1
Hi Christoph,

On 3/1/21 9:42 AM, Christoph Hellwig wrote:
> Signed-off-by: Christoph Hellwig <hch@lst.de>
> ---
>  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c | 40 ++++++---------------
>  drivers/iommu/arm/arm-smmu/arm-smmu.c       | 30 ++++++++++------
>  drivers/iommu/intel/iommu.c                 | 28 +++++----------
>  drivers/iommu/iommu.c                       |  8 +++++
>  drivers/vfio/vfio_iommu_type1.c             |  5 +--
>  include/linux/iommu.h                       |  4 ++-
>  6 files changed, 50 insertions(+), 65 deletions(-)

As mentionned by Robin, there are series planning to use
DOMAIN_ATTR_NESTING to get info about the nested caps of the iommu (ARM
and Intel):

[Patch v8 00/10] vfio: expose virtual Shared Virtual Addressing to VMs
patches 1, 2, 3

Is the plan to introduce a new domain_get_nesting_info ops then?

Thanks

Eric	


> 
> 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 bf96172e8c1f71..8e6fee3ea454d3 100644
> --- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> +++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
> @@ -2466,41 +2466,21 @@ static void arm_smmu_dma_enable_flush_queue(struct iommu_domain *domain)
>  	to_smmu_domain(domain)->non_strict = true;
>  }
>  
> -static int arm_smmu_domain_set_attr(struct iommu_domain *domain,
> -				    enum iommu_attr attr, void *data)
> +static int arm_smmu_domain_enable_nesting(struct iommu_domain *domain)
>  {
> -	int ret = 0;
>  	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
> +	int ret = -EPERM;
>  
> -	mutex_lock(&smmu_domain->init_mutex);
> +	if (domain->type != IOMMU_DOMAIN_UNMANAGED)
> +		return -EINVAL;
>  
> -	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:
> -		ret = -ENODEV;
> -		break;
> -	default:
> -		ret = -EINVAL;
> +	mutex_lock(&smmu_domain->init_mutex);
> +	if (!smmu_domain->smmu) {
> +		smmu_domain->stage = ARM_SMMU_DOMAIN_NESTED;
> +		ret = 0;
>  	}
> -
> -out_unlock:
>  	mutex_unlock(&smmu_domain->init_mutex);
> +
>  	return ret;
>  }
>  
> @@ -2603,7 +2583,7 @@ static struct iommu_ops arm_smmu_ops = {
>  	.device_group		= arm_smmu_device_group,
>  	.dma_use_flush_queue	= arm_smmu_dma_use_flush_queue,
>  	.dma_enable_flush_queue	= arm_smmu_dma_enable_flush_queue,
> -	.domain_set_attr	= arm_smmu_domain_set_attr,
> +	.domain_enable_nesting	= arm_smmu_domain_enable_nesting,
>  	.of_xlate		= arm_smmu_of_xlate,
>  	.get_resv_regions	= arm_smmu_get_resv_regions,
>  	.put_resv_regions	= generic_iommu_put_resv_regions,
> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> index e7893e96f5177a..2e17d990d04481 100644
> --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
> @@ -1497,6 +1497,24 @@ static void arm_smmu_dma_enable_flush_queue(struct iommu_domain *domain)
>  	to_smmu_domain(domain)->pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
>  }
>  
> +static int arm_smmu_domain_enable_nesting(struct iommu_domain *domain)
> +{
> +	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
> +	int ret = -EPERM;
> +	
> +	if (domain->type != IOMMU_DOMAIN_UNMANAGED)
> +		return -EINVAL;
> +
> +	mutex_lock(&smmu_domain->init_mutex);
> +	if (!smmu_domain->smmu) {
> +		smmu_domain->stage = ARM_SMMU_DOMAIN_NESTED;
> +		ret = 0;
> +	}
> +	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)
>  {
> @@ -1508,17 +1526,6 @@ 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;
>  
> @@ -1603,6 +1610,7 @@ static struct iommu_ops arm_smmu_ops = {
>  	.dma_use_flush_queue	= arm_smmu_dma_use_flush_queue,
>  	.dma_enable_flush_queue	= arm_smmu_dma_enable_flush_queue,
>  	.domain_set_attr	= arm_smmu_domain_set_attr,
> +	.domain_enable_nesting	= arm_smmu_domain_enable_nesting,
>  	.of_xlate		= arm_smmu_of_xlate,
>  	.get_resv_regions	= arm_smmu_get_resv_regions,
>  	.put_resv_regions	= generic_iommu_put_resv_regions,
> diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
> index eaa80c33f4bc91..0f1374d6612a60 100644
> --- a/drivers/iommu/intel/iommu.c
> +++ b/drivers/iommu/intel/iommu.c
> @@ -5423,32 +5423,22 @@ static bool intel_iommu_is_attach_deferred(struct iommu_domain *domain,
>  }
>  
>  static int
> -intel_iommu_domain_set_attr(struct iommu_domain *domain,
> -			    enum iommu_attr attr, void *data)
> +intel_iommu_domain_enable_nesting(struct iommu_domain *domain)
>  {
>  	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() &&
> -		    list_empty(&dmar_domain->devices)) {
> -			dmar_domain->flags |= DOMAIN_FLAG_NESTING_MODE;
> -			dmar_domain->flags &= ~DOMAIN_FLAG_USE_FIRST_LEVEL;
> -		} else {
> -			ret = -ENODEV;
> -		}
> -		spin_unlock_irqrestore(&device_domain_lock, flags);
> -		break;
> -	default:
> -		ret = -EINVAL;
> -		break;
> +	spin_lock_irqsave(&device_domain_lock, flags);
> +	if (nested_mode_support() && list_empty(&dmar_domain->devices)) {
> +		dmar_domain->flags |= DOMAIN_FLAG_NESTING_MODE;
> +		dmar_domain->flags &= ~DOMAIN_FLAG_USE_FIRST_LEVEL;
> +		ret = 0;
>  	}
> +	spin_unlock_irqrestore(&device_domain_lock, flags);
>  
>  	return ret;
>  }
> @@ -5556,7 +5546,7 @@ const struct iommu_ops intel_iommu_ops = {
>  	.domain_alloc		= intel_iommu_domain_alloc,
>  	.domain_free		= intel_iommu_domain_free,
>  	.dma_use_flush_queue	= intel_iommu_dma_use_flush_queue,
> -	.domain_set_attr	= intel_iommu_domain_set_attr,
> +	.domain_enable_nesting	= intel_iommu_domain_enable_nesting,
>  	.attach_dev		= intel_iommu_attach_device,
>  	.detach_dev		= intel_iommu_detach_device,
>  	.aux_attach_dev		= intel_iommu_aux_attach_device,
> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
> index 0f12c4d58cdc42..2e9e058501a953 100644
> --- a/drivers/iommu/iommu.c
> +++ b/drivers/iommu/iommu.c
> @@ -2685,6 +2685,14 @@ int iommu_domain_set_attr(struct iommu_domain *domain,
>  }
>  EXPORT_SYMBOL_GPL(iommu_domain_set_attr);
>  
> +int iommu_domain_enable_nesting(struct iommu_domain *domain)
> +{
> +	if (!domain->ops->domain_enable_nesting)
> +		return -EINVAL;
> +	return domain->ops->domain_enable_nesting(domain);
> +}
> +EXPORT_SYMBOL_GPL(iommu_domain_enable_nesting);
> +
>  void iommu_get_resv_regions(struct device *dev, struct list_head *list)
>  {
>  	const struct iommu_ops *ops = dev->bus->iommu_ops;
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index c8e57f22f421c5..9cea4d80dd66ed 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/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_domain_set_attr(domain->domain, DOMAIN_ATTR_NESTING,
> -					    &attr);
> +		ret = iommu_domain_enable_nesting(domain->domain);
>  		if (ret)
>  			goto out_domain;
>  	}
> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
> index f30de33c6ff56e..aed88aa3bd3edf 100644
> --- a/include/linux/iommu.h
> +++ b/include/linux/iommu.h
> @@ -107,7 +107,6 @@ enum iommu_cap {
>   */
>  
>  enum iommu_attr {
> -	DOMAIN_ATTR_NESTING,	/* two stages of translation */
>  	DOMAIN_ATTR_IO_PGTABLE_CFG,
>  	DOMAIN_ATTR_MAX,
>  };
> @@ -196,6 +195,7 @@ struct iommu_iotlb_gather {
>   * @dma_use_flush_queue: Returns %true if a DMA flush queue is used
>   * @dma_enable_flush_queue: Try to enable the DMA flush queue
>   * @domain_set_attr: Change domain attributes
> + * @domain_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
> @@ -248,6 +248,7 @@ struct iommu_ops {
>  	void (*dma_enable_flush_queue)(struct iommu_domain *domain);
>  	int (*domain_set_attr)(struct iommu_domain *domain,
>  			       enum iommu_attr attr, void *data);
> +	int (*domain_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);
> @@ -494,6 +495,7 @@ extern struct iommu_domain *iommu_group_default_domain(struct iommu_group *);
>  bool iommu_dma_use_flush_queue(struct iommu_domain *domain);
>  extern int iommu_domain_set_attr(struct iommu_domain *domain, enum iommu_attr,
>  				 void *data);
> +int iommu_domain_enable_nesting(struct iommu_domain *domain);
>  
>  extern int report_iommu_fault(struct iommu_domain *domain, struct device *dev,
>  			      unsigned long iova, int flags);
>
Christoph Hellwig March 14, 2021, 3:58 p.m. UTC | #2
On Sun, Mar 14, 2021 at 11:44:52AM +0100, Auger Eric wrote:
> As mentionned by Robin, there are series planning to use
> DOMAIN_ATTR_NESTING to get info about the nested caps of the iommu (ARM
> and Intel):
> 
> [Patch v8 00/10] vfio: expose virtual Shared Virtual Addressing to VMs
> patches 1, 2, 3
> 
> Is the plan to introduce a new domain_get_nesting_info ops then?

The plan as usual would be to add it the series adding that support.
Not sure what the merge plans are - if the series is ready to be
merged I could rebase on top of it, otherwise that series will need
to add the method.
Auger Eric March 15, 2021, 7:52 a.m. UTC | #3
Hi Christoph,

On 3/14/21 4:58 PM, Christoph Hellwig wrote:
> On Sun, Mar 14, 2021 at 11:44:52AM +0100, Auger Eric wrote:
>> As mentionned by Robin, there are series planning to use
>> DOMAIN_ATTR_NESTING to get info about the nested caps of the iommu (ARM
>> and Intel):
>>
>> [Patch v8 00/10] vfio: expose virtual Shared Virtual Addressing to VMs
>> patches 1, 2, 3
>>
>> Is the plan to introduce a new domain_get_nesting_info ops then?
> 
> The plan as usual would be to add it the series adding that support.
> Not sure what the merge plans are - if the series is ready to be
> merged I could rebase on top of it, otherwise that series will need
> to add the method.
OK I think your series may be upstreamed first.

Thanks

Eric
>
Tian, Kevin March 25, 2021, 6:12 a.m. UTC | #4
> From: Auger Eric
> Sent: Monday, March 15, 2021 3:52 PM
> To: Christoph Hellwig <hch@lst.de>
> Cc: kvm@vger.kernel.org; Will Deacon <will@kernel.org>; linuxppc-
> dev@lists.ozlabs.org; dri-devel@lists.freedesktop.org; Li Yang
> <leoyang.li@nxp.com>; iommu@lists.linux-foundation.org;
> 
> Hi Christoph,
> 
> On 3/14/21 4:58 PM, Christoph Hellwig wrote:
> > On Sun, Mar 14, 2021 at 11:44:52AM +0100, Auger Eric wrote:
> >> As mentionned by Robin, there are series planning to use
> >> DOMAIN_ATTR_NESTING to get info about the nested caps of the iommu
> (ARM
> >> and Intel):
> >>
> >> [Patch v8 00/10] vfio: expose virtual Shared Virtual Addressing to VMs
> >> patches 1, 2, 3
> >>
> >> Is the plan to introduce a new domain_get_nesting_info ops then?
> >
> > The plan as usual would be to add it the series adding that support.
> > Not sure what the merge plans are - if the series is ready to be
> > merged I could rebase on top of it, otherwise that series will need
> > to add the method.
> OK I think your series may be upstreamed first.
> 

Agree. The vSVA series is still undergoing a refactor according to Jason's
comment thus won't be ready in short term. It's better to let this one
go in first.

Thanks
Kevin
Christoph Hellwig March 25, 2021, 6:51 a.m. UTC | #5
On Thu, Mar 25, 2021 at 06:12:37AM +0000, Tian, Kevin wrote:
> Agree. The vSVA series is still undergoing a refactor according to Jason's
> comment thus won't be ready in short term. It's better to let this one
> go in first.

Would be great to get a few more reviews while we're at it :)
diff mbox series

Patch

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 bf96172e8c1f71..8e6fee3ea454d3 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2466,41 +2466,21 @@  static void arm_smmu_dma_enable_flush_queue(struct iommu_domain *domain)
 	to_smmu_domain(domain)->non_strict = true;
 }
 
-static int arm_smmu_domain_set_attr(struct iommu_domain *domain,
-				    enum iommu_attr attr, void *data)
+static int arm_smmu_domain_enable_nesting(struct iommu_domain *domain)
 {
-	int ret = 0;
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+	int ret = -EPERM;
 
-	mutex_lock(&smmu_domain->init_mutex);
+	if (domain->type != IOMMU_DOMAIN_UNMANAGED)
+		return -EINVAL;
 
-	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:
-		ret = -ENODEV;
-		break;
-	default:
-		ret = -EINVAL;
+	mutex_lock(&smmu_domain->init_mutex);
+	if (!smmu_domain->smmu) {
+		smmu_domain->stage = ARM_SMMU_DOMAIN_NESTED;
+		ret = 0;
 	}
-
-out_unlock:
 	mutex_unlock(&smmu_domain->init_mutex);
+
 	return ret;
 }
 
@@ -2603,7 +2583,7 @@  static struct iommu_ops arm_smmu_ops = {
 	.device_group		= arm_smmu_device_group,
 	.dma_use_flush_queue	= arm_smmu_dma_use_flush_queue,
 	.dma_enable_flush_queue	= arm_smmu_dma_enable_flush_queue,
-	.domain_set_attr	= arm_smmu_domain_set_attr,
+	.domain_enable_nesting	= arm_smmu_domain_enable_nesting,
 	.of_xlate		= arm_smmu_of_xlate,
 	.get_resv_regions	= arm_smmu_get_resv_regions,
 	.put_resv_regions	= generic_iommu_put_resv_regions,
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index e7893e96f5177a..2e17d990d04481 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -1497,6 +1497,24 @@  static void arm_smmu_dma_enable_flush_queue(struct iommu_domain *domain)
 	to_smmu_domain(domain)->pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
 }
 
+static int arm_smmu_domain_enable_nesting(struct iommu_domain *domain)
+{
+	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
+	int ret = -EPERM;
+	
+	if (domain->type != IOMMU_DOMAIN_UNMANAGED)
+		return -EINVAL;
+
+	mutex_lock(&smmu_domain->init_mutex);
+	if (!smmu_domain->smmu) {
+		smmu_domain->stage = ARM_SMMU_DOMAIN_NESTED;
+		ret = 0;
+	}
+	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)
 {
@@ -1508,17 +1526,6 @@  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;
 
@@ -1603,6 +1610,7 @@  static struct iommu_ops arm_smmu_ops = {
 	.dma_use_flush_queue	= arm_smmu_dma_use_flush_queue,
 	.dma_enable_flush_queue	= arm_smmu_dma_enable_flush_queue,
 	.domain_set_attr	= arm_smmu_domain_set_attr,
+	.domain_enable_nesting	= arm_smmu_domain_enable_nesting,
 	.of_xlate		= arm_smmu_of_xlate,
 	.get_resv_regions	= arm_smmu_get_resv_regions,
 	.put_resv_regions	= generic_iommu_put_resv_regions,
diff --git a/drivers/iommu/intel/iommu.c b/drivers/iommu/intel/iommu.c
index eaa80c33f4bc91..0f1374d6612a60 100644
--- a/drivers/iommu/intel/iommu.c
+++ b/drivers/iommu/intel/iommu.c
@@ -5423,32 +5423,22 @@  static bool intel_iommu_is_attach_deferred(struct iommu_domain *domain,
 }
 
 static int
-intel_iommu_domain_set_attr(struct iommu_domain *domain,
-			    enum iommu_attr attr, void *data)
+intel_iommu_domain_enable_nesting(struct iommu_domain *domain)
 {
 	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() &&
-		    list_empty(&dmar_domain->devices)) {
-			dmar_domain->flags |= DOMAIN_FLAG_NESTING_MODE;
-			dmar_domain->flags &= ~DOMAIN_FLAG_USE_FIRST_LEVEL;
-		} else {
-			ret = -ENODEV;
-		}
-		spin_unlock_irqrestore(&device_domain_lock, flags);
-		break;
-	default:
-		ret = -EINVAL;
-		break;
+	spin_lock_irqsave(&device_domain_lock, flags);
+	if (nested_mode_support() && list_empty(&dmar_domain->devices)) {
+		dmar_domain->flags |= DOMAIN_FLAG_NESTING_MODE;
+		dmar_domain->flags &= ~DOMAIN_FLAG_USE_FIRST_LEVEL;
+		ret = 0;
 	}
+	spin_unlock_irqrestore(&device_domain_lock, flags);
 
 	return ret;
 }
@@ -5556,7 +5546,7 @@  const struct iommu_ops intel_iommu_ops = {
 	.domain_alloc		= intel_iommu_domain_alloc,
 	.domain_free		= intel_iommu_domain_free,
 	.dma_use_flush_queue	= intel_iommu_dma_use_flush_queue,
-	.domain_set_attr	= intel_iommu_domain_set_attr,
+	.domain_enable_nesting	= intel_iommu_domain_enable_nesting,
 	.attach_dev		= intel_iommu_attach_device,
 	.detach_dev		= intel_iommu_detach_device,
 	.aux_attach_dev		= intel_iommu_aux_attach_device,
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 0f12c4d58cdc42..2e9e058501a953 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2685,6 +2685,14 @@  int iommu_domain_set_attr(struct iommu_domain *domain,
 }
 EXPORT_SYMBOL_GPL(iommu_domain_set_attr);
 
+int iommu_domain_enable_nesting(struct iommu_domain *domain)
+{
+	if (!domain->ops->domain_enable_nesting)
+		return -EINVAL;
+	return domain->ops->domain_enable_nesting(domain);
+}
+EXPORT_SYMBOL_GPL(iommu_domain_enable_nesting);
+
 void iommu_get_resv_regions(struct device *dev, struct list_head *list)
 {
 	const struct iommu_ops *ops = dev->bus->iommu_ops;
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index c8e57f22f421c5..9cea4d80dd66ed 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/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_domain_set_attr(domain->domain, DOMAIN_ATTR_NESTING,
-					    &attr);
+		ret = iommu_domain_enable_nesting(domain->domain);
 		if (ret)
 			goto out_domain;
 	}
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index f30de33c6ff56e..aed88aa3bd3edf 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -107,7 +107,6 @@  enum iommu_cap {
  */
 
 enum iommu_attr {
-	DOMAIN_ATTR_NESTING,	/* two stages of translation */
 	DOMAIN_ATTR_IO_PGTABLE_CFG,
 	DOMAIN_ATTR_MAX,
 };
@@ -196,6 +195,7 @@  struct iommu_iotlb_gather {
  * @dma_use_flush_queue: Returns %true if a DMA flush queue is used
  * @dma_enable_flush_queue: Try to enable the DMA flush queue
  * @domain_set_attr: Change domain attributes
+ * @domain_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
@@ -248,6 +248,7 @@  struct iommu_ops {
 	void (*dma_enable_flush_queue)(struct iommu_domain *domain);
 	int (*domain_set_attr)(struct iommu_domain *domain,
 			       enum iommu_attr attr, void *data);
+	int (*domain_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);
@@ -494,6 +495,7 @@  extern struct iommu_domain *iommu_group_default_domain(struct iommu_group *);
 bool iommu_dma_use_flush_queue(struct iommu_domain *domain);
 extern int iommu_domain_set_attr(struct iommu_domain *domain, enum iommu_attr,
 				 void *data);
+int iommu_domain_enable_nesting(struct iommu_domain *domain);
 
 extern int report_iommu_fault(struct iommu_domain *domain, struct device *dev,
 			      unsigned long iova, int flags);