diff mbox series

[v7,5/6] iommu/arm-smmu-v3: Add support for non-strict mode

Message ID 4f9444c7224ea0e6e4cef8ddbf77bb5292a383e3.1536935328.git.robin.murphy@arm.com
State New
Headers show
Series [v7,1/6] iommu/arm-smmu-v3: Implement flush_iotlb_all hook | expand

Commit Message

Robin Murphy Sept. 14, 2018, 2:30 p.m. UTC
From: Zhen Lei <thunder.leizhen@huawei.com>


Dynamically choose strict or non-strict mode for page table config based
on the iommu domain type.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>

[rm: convert to domain attribute]
Signed-off-by: Robin Murphy <robin.murphy@arm.com>

---
 drivers/iommu/arm-smmu-v3.c | 30 ++++++++++++++++++++++++------
 1 file changed, 24 insertions(+), 6 deletions(-)

-- 
2.19.0.dirty

Comments

Will Deacon Sept. 18, 2018, 5:10 p.m. UTC | #1
On Fri, Sep 14, 2018 at 03:30:23PM +0100, Robin Murphy wrote:
> From: Zhen Lei <thunder.leizhen@huawei.com>

> 

> Dynamically choose strict or non-strict mode for page table config based

> on the iommu domain type.


It's the domain type in conjunction with the attribute that determines
whether we use lazy or strict invalidation.

> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>

> [rm: convert to domain attribute]

> Signed-off-by: Robin Murphy <robin.murphy@arm.com>

> ---

>  drivers/iommu/arm-smmu-v3.c | 30 ++++++++++++++++++++++++------

>  1 file changed, 24 insertions(+), 6 deletions(-)

> 

> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c

> index f10c852479fc..7bbfa5f7ce8e 100644

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

> +++ b/drivers/iommu/arm-smmu-v3.c

> @@ -612,6 +612,7 @@ struct arm_smmu_domain {

>  	struct mutex			init_mutex; /* Protects smmu pointer */

>  

>  	struct io_pgtable_ops		*pgtbl_ops;

> +	bool				non_strict;

>  

>  	enum arm_smmu_domain_stage	stage;

>  	union {

> @@ -1633,6 +1634,9 @@ static int arm_smmu_domain_finalise(struct iommu_domain *domain)

>  	if (smmu->features & ARM_SMMU_FEAT_COHERENCY)

>  		pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_NO_DMA;

>  

> +	if (smmu_domain->non_strict)

> +		pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;

> +

>  	pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain);

>  	if (!pgtbl_ops)

>  		return -ENOMEM;

> @@ -1934,13 +1938,17 @@ static int arm_smmu_domain_get_attr(struct iommu_domain *domain,

>  {

>  	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);

>  

> -	if (domain->type != IOMMU_DOMAIN_UNMANAGED)

> -		return -EINVAL;

> -

>  	switch (attr) {

>  	case DOMAIN_ATTR_NESTING:

> +		if (domain->type != IOMMU_DOMAIN_UNMANAGED)

> +			return -EINVAL;

>  		*(int *)data = (smmu_domain->stage == ARM_SMMU_DOMAIN_NESTED);

>  		return 0;

> +	case DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE:

> +		if (domain->type != IOMMU_DOMAIN_DMA)

> +			return -EINVAL;

> +		*(int *)data = smmu_domain->non_strict;

> +		return 0;

>  	default:

>  		return -ENODEV;


Hmm, there's a change in behaviour here (and also in the set function)
which is that unknown attributes now return -ENODEV for managed domains
instead of -EINVAL. I don't know if that's a problem, but I'd be inclined
to switch on the domain type and then have a nested switch for the supported
attributes.

Will
Robin Murphy Sept. 18, 2018, 7:09 p.m. UTC | #2
On 2018-09-18 6:10 PM, Will Deacon wrote:
> On Fri, Sep 14, 2018 at 03:30:23PM +0100, Robin Murphy wrote:

>> From: Zhen Lei <thunder.leizhen@huawei.com>

>>

>> Dynamically choose strict or non-strict mode for page table config based

>> on the iommu domain type.

> 

> It's the domain type in conjunction with the attribute that determines

> whether we use lazy or strict invalidation.

> 

>> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>

>> [rm: convert to domain attribute]

>> Signed-off-by: Robin Murphy <robin.murphy@arm.com>

>> ---

>>   drivers/iommu/arm-smmu-v3.c | 30 ++++++++++++++++++++++++------

>>   1 file changed, 24 insertions(+), 6 deletions(-)

>>

>> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c

>> index f10c852479fc..7bbfa5f7ce8e 100644

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

>> +++ b/drivers/iommu/arm-smmu-v3.c

>> @@ -612,6 +612,7 @@ struct arm_smmu_domain {

>>   	struct mutex			init_mutex; /* Protects smmu pointer */

>>   

>>   	struct io_pgtable_ops		*pgtbl_ops;

>> +	bool				non_strict;

>>   

>>   	enum arm_smmu_domain_stage	stage;

>>   	union {

>> @@ -1633,6 +1634,9 @@ static int arm_smmu_domain_finalise(struct iommu_domain *domain)

>>   	if (smmu->features & ARM_SMMU_FEAT_COHERENCY)

>>   		pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_NO_DMA;

>>   

>> +	if (smmu_domain->non_strict)

>> +		pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;

>> +

>>   	pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain);

>>   	if (!pgtbl_ops)

>>   		return -ENOMEM;

>> @@ -1934,13 +1938,17 @@ static int arm_smmu_domain_get_attr(struct iommu_domain *domain,

>>   {

>>   	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);

>>   

>> -	if (domain->type != IOMMU_DOMAIN_UNMANAGED)

>> -		return -EINVAL;

>> -

>>   	switch (attr) {

>>   	case DOMAIN_ATTR_NESTING:

>> +		if (domain->type != IOMMU_DOMAIN_UNMANAGED)

>> +			return -EINVAL;

>>   		*(int *)data = (smmu_domain->stage == ARM_SMMU_DOMAIN_NESTED);

>>   		return 0;

>> +	case DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE:

>> +		if (domain->type != IOMMU_DOMAIN_DMA)

>> +			return -EINVAL;

>> +		*(int *)data = smmu_domain->non_strict;

>> +		return 0;

>>   	default:

>>   		return -ENODEV;

> 

> Hmm, there's a change in behaviour here (and also in the set function)

> which is that unknown attributes now return -ENODEV for managed domains

> instead of -EINVAL. I don't know if that's a problem, but I'd be inclined

> to switch on the domain type and then have a nested switch for the supported

> attributes.


Sure, a nested switch did actually cross my mind, but I was worried it 
might be a little boilerplate-heavy since there's still only one of each 
case (and this quick'n'dirty copy-paste job didn't need any thought...)

If that's your preference too, though, I'll respin both driver patches 
that way.

Robin.
diff mbox series

Patch

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index f10c852479fc..7bbfa5f7ce8e 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -612,6 +612,7 @@  struct arm_smmu_domain {
 	struct mutex			init_mutex; /* Protects smmu pointer */
 
 	struct io_pgtable_ops		*pgtbl_ops;
+	bool				non_strict;
 
 	enum arm_smmu_domain_stage	stage;
 	union {
@@ -1633,6 +1634,9 @@  static int arm_smmu_domain_finalise(struct iommu_domain *domain)
 	if (smmu->features & ARM_SMMU_FEAT_COHERENCY)
 		pgtbl_cfg.quirks = IO_PGTABLE_QUIRK_NO_DMA;
 
+	if (smmu_domain->non_strict)
+		pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
+
 	pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain);
 	if (!pgtbl_ops)
 		return -ENOMEM;
@@ -1934,13 +1938,17 @@  static int arm_smmu_domain_get_attr(struct iommu_domain *domain,
 {
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
 
-	if (domain->type != IOMMU_DOMAIN_UNMANAGED)
-		return -EINVAL;
-
 	switch (attr) {
 	case DOMAIN_ATTR_NESTING:
+		if (domain->type != IOMMU_DOMAIN_UNMANAGED)
+			return -EINVAL;
 		*(int *)data = (smmu_domain->stage == ARM_SMMU_DOMAIN_NESTED);
 		return 0;
+	case DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE:
+		if (domain->type != IOMMU_DOMAIN_DMA)
+			return -EINVAL;
+		*(int *)data = smmu_domain->non_strict;
+		return 0;
 	default:
 		return -ENODEV;
 	}
@@ -1952,13 +1960,15 @@  static int arm_smmu_domain_set_attr(struct iommu_domain *domain,
 	int ret = 0;
 	struct arm_smmu_domain *smmu_domain = to_smmu_domain(domain);
 
-	if (domain->type != IOMMU_DOMAIN_UNMANAGED)
-		return -EINVAL;
-
 	mutex_lock(&smmu_domain->init_mutex);
 
 	switch (attr) {
 	case DOMAIN_ATTR_NESTING:
+		if (domain->type != IOMMU_DOMAIN_UNMANAGED) {
+			ret = -EINVAL;
+			goto out_unlock;
+		}
+
 		if (smmu_domain->smmu) {
 			ret = -EPERM;
 			goto out_unlock;
@@ -1969,6 +1979,14 @@  static int arm_smmu_domain_set_attr(struct iommu_domain *domain,
 		else
 			smmu_domain->stage = ARM_SMMU_DOMAIN_S1;
 
+		break;
+	case DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE:
+		if (domain->type != IOMMU_DOMAIN_DMA) {
+			ret = -EINVAL;
+			goto out_unlock;
+		}
+
+		smmu_domain->non_strict = *(int *)data;
 		break;
 	default:
 		ret = -ENODEV;