diff mbox series

[v4,4/5] iommu/arm-smmu-v3: add support for non-strict mode

Message ID 1533558424-16748-5-git-send-email-thunder.leizhen@huawei.com
State New
Headers show
Series add non-strict mode support for arm-smmu-v3 | expand

Commit Message

Leizhen (ThunderTown) Aug. 6, 2018, 12:27 p.m. UTC
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>

---
 drivers/iommu/arm-smmu-v3.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

--
1.8.3

Comments

Robin Murphy Aug. 9, 2018, 11:06 a.m. UTC | #1
On 06/08/18 13:27, Zhen Lei wrote:
> 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>

> ---

>   drivers/iommu/arm-smmu-v3.c | 7 ++++++-

>   1 file changed, 6 insertions(+), 1 deletion(-)

> 

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

> index 2f1304b..904bc1e 100644

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

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

> @@ -1622,6 +1622,11 @@ 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 (domain->type == IOMMU_DOMAIN_DMA) {

> +		domain->non_strict = 1;

> +		pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;

> +	}

> +

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

>   	if (!pgtbl_ops)

>   		return -ENOMEM;

> @@ -1782,7 +1787,7 @@ static void arm_smmu_iotlb_sync(struct iommu_domain *domain)

>   {

>   	struct arm_smmu_device *smmu = to_smmu_domain(domain)->smmu;

> 

> -	if (smmu)

> +	if (smmu && !domain->non_strict)


That doesn't smell right - even in non-strict domains we still need 
stuff like walk cache invalidations for non-leaf unmaps to be 
synchronous, so we can't just ignore all sync operations at the driver 
level. I think the right thing to do to elide the "normal" sync on unmap 
is to first convert __iommu_dma_unmap to use 
iommu_unmap_fast()/iommu_tlb_sync(), then make it not issue that sync at 
all for non-strict domains.

Robin.

>   		__arm_smmu_tlb_sync(smmu);

>   }

> 

> --

> 1.8.3

> 

>
Leizhen (ThunderTown) Aug. 14, 2018, 1:49 a.m. UTC | #2
On 2018/8/9 19:06, Robin Murphy wrote:
> On 06/08/18 13:27, Zhen Lei wrote:

>> 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>

>> ---

>>   drivers/iommu/arm-smmu-v3.c | 7 ++++++-

>>   1 file changed, 6 insertions(+), 1 deletion(-)

>>

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

>> index 2f1304b..904bc1e 100644

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

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

>> @@ -1622,6 +1622,11 @@ 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 (domain->type == IOMMU_DOMAIN_DMA) {

>> +        domain->non_strict = 1;

>> +        pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;

>> +    }

>> +

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

>>       if (!pgtbl_ops)

>>           return -ENOMEM;

>> @@ -1782,7 +1787,7 @@ static void arm_smmu_iotlb_sync(struct iommu_domain *domain)

>>   {

>>       struct arm_smmu_device *smmu = to_smmu_domain(domain)->smmu;

>>

>> -    if (smmu)

>> +    if (smmu && !domain->non_strict)

> 

> That doesn't smell right - even in non-strict domains we still need stuff like walk cache invalidations for non-leaf unmaps to be synchronous, so we can't just ignore all sync operations at the driver level. I think the right thing to do to elide the "normal" sync on unmap is to first convert __iommu_dma_unmap to use iommu_unmap_fast()/iommu_tlb_sync(), then make it not issue that sync at all for non-strict domains.


OK, I will try it.

> 

> Robin.

> 

>>           __arm_smmu_tlb_sync(smmu);

>>   }

>>

>> -- 

>> 1.8.3

>>

>>

> 

> .

> 


-- 
Thanks!
BestRegards
diff mbox series

Patch

diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
index 2f1304b..904bc1e 100644
--- a/drivers/iommu/arm-smmu-v3.c
+++ b/drivers/iommu/arm-smmu-v3.c
@@ -1622,6 +1622,11 @@  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 (domain->type == IOMMU_DOMAIN_DMA) {
+		domain->non_strict = 1;
+		pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
+	}
+
 	pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain);
 	if (!pgtbl_ops)
 		return -ENOMEM;
@@ -1782,7 +1787,7 @@  static void arm_smmu_iotlb_sync(struct iommu_domain *domain)
 {
 	struct arm_smmu_device *smmu = to_smmu_domain(domain)->smmu;

-	if (smmu)
+	if (smmu && !domain->non_strict)
 		__arm_smmu_tlb_sync(smmu);
 }