Re: [PATCH 18/23] iommu: Express DMA strictness via the domain type

2021-07-26 Thread Robin Murphy 

On 2021-07-26 13:29, Lu Baolu wrote:
[...]

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index b1af1ff324c5..a114a7ad88ec 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -363,13 +363,15 @@ static int iommu_dma_init_domain(struct 
iommu_domain *domain, dma_addr_t base,

  init_iova_domain(iovad, 1UL << order, base_pfn);
-    if (!cookie->fq_domain && !dev_is_untrusted(dev) &&
-    domain->ops->flush_iotlb_all && 
!iommu_get_dma_strict(domain)) {

+    if (domain->type == IOMMU_DOMAIN_DMA_FQ && !cookie->fq_domain &&
+    domain->ops->flush_iotlb_all) {


Perhaps we can remove the ops->flush_iotlb_all check with the
assumption that any vendor iommu driver with DMA_FQ domain support
should always provides this callback?


Oh yes, indeed it wouldn't make sense for a driver to claim 
IOMMU_DOMAIN_DMA_FQ support but not implement the one thing that that 
needs the driver to provide. That's yet another neat little cleanup, thanks!


Robin.
___
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

Re: [PATCH 18/23] iommu: Express DMA strictness via the domain type

2021-07-26 Thread Lu Baolu 

On 2021/7/26 16:27, Robin Murphy wrote:

On 2021-07-24 06:29, Lu Baolu wrote:

Hi Robin,

On 2021/7/22 2:20, Robin Murphy wrote:

Eliminate the iommu_get_dma_strict() indirection and pipe the
information through the domain type from the beginning. Besides
the flow simplification this also has several nice side-effects:

  - Automatically implies strict mode for untrusted devices by
    virtue of their IOMMU_DOMAIN_DMA override.
  - Ensures that we only ends up using flush queues for drivers
    which are aware of them and can actually benefit.


Is this expressed by vendor iommu driver has ops->flush_iotlb_all?


No, it's literally whether ->domain_alloc accepts the DMA_DOMAIN_FQ type 
or not.



  - Allows us to handle flush queue init failure by falling back
    to strict mode instead of leaving it to possibly blow up later.

Signed-off-by: Robin Murphy 
---
  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c |  2 +-
  drivers/iommu/arm/arm-smmu/arm-smmu.c   |  2 +-
  drivers/iommu/dma-iommu.c   | 10 ++
  drivers/iommu/iommu.c   | 14 --
  include/linux/iommu.h   |  1 -
  5 files changed, 12 insertions(+), 17 deletions(-)

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 fa41026d272e..260b560d0075 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2175,7 +2175,7 @@ static int arm_smmu_domain_finalise(struct 
iommu_domain *domain,

  .iommu_dev    = smmu->dev,
  };
-    if (!iommu_get_dma_strict(domain))
+    if (domain->type == IOMMU_DOMAIN_DMA_FQ)
  pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
  pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain);
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c 
b/drivers/iommu/arm/arm-smmu/arm-smmu.c

index dbc14c265b15..2c717f3be056 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -765,7 +765,7 @@ static int arm_smmu_init_domain_context(struct 
iommu_domain *domain,

  .iommu_dev    = smmu->dev,
  };
-    if (!iommu_get_dma_strict(domain))
+    if (domain->type == IOMMU_DOMAIN_DMA_FQ)
  pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
  if (smmu->impl && smmu->impl->init_context) {
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index b1af1ff324c5..a114a7ad88ec 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -363,13 +363,15 @@ static int iommu_dma_init_domain(struct 
iommu_domain *domain, dma_addr_t base,

  init_iova_domain(iovad, 1UL << order, base_pfn);
-    if (!cookie->fq_domain && !dev_is_untrusted(dev) &&
-    domain->ops->flush_iotlb_all && 
!iommu_get_dma_strict(domain)) {

+    if (domain->type == IOMMU_DOMAIN_DMA_FQ && !cookie->fq_domain &&
+    domain->ops->flush_iotlb_all) {


Perhaps we can remove the ops->flush_iotlb_all check with the
assumption that any vendor iommu driver with DMA_FQ domain support
should always provides this callback?

Best regards,
baolu


  if (init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all,
-  iommu_dma_entry_dtor))
+  iommu_dma_entry_dtor)) {
  pr_warn("iova flush queue initialization failed\n");
-    else
+    domain->type = IOMMU_DOMAIN_DMA;
+    } else {
  cookie->fq_domain = domain;
+    }
  }
  return iova_reserve_iommu_regions(dev, domain);
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 8333c334891e..d7eaacae0944 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -135,6 +135,9 @@ static int __init iommu_subsys_init(void)
  }
  }
+    if (!iommu_default_passthrough() && !iommu_dma_strict)
+    iommu_def_domain_type = IOMMU_DOMAIN_DMA_FQ;
+
  pr_info("Default domain type: %s %s\n",
  iommu_domain_type_str(iommu_def_domain_type),
  (iommu_cmd_line & IOMMU_CMD_LINE_DMA_API) ?
@@ -352,15 +355,6 @@ void iommu_set_dma_strict(bool strict)
  iommu_dma_strict = strict;
  }
-bool iommu_get_dma_strict(struct iommu_domain *domain)
-{
-    /* only allow lazy flushing for DMA domains */
-    if (domain->type == IOMMU_DOMAIN_DMA)
-    return iommu_dma_strict;
-    return true;
-}
-EXPORT_SYMBOL_GPL(iommu_get_dma_strict);
-
  static ssize_t iommu_group_attr_show(struct kobject *kobj,
   struct attribute *__attr, char *buf)
  {
@@ -764,7 +758,7 @@ static int 
iommu_create_device_direct_mappings(struct iommu_group *group,

  unsigned long pg_size;
  int ret = 0;
-    if (!domain || domain->type != IOMMU_DOMAIN_DMA)
+    if (!domain || !(domain->type & __IOMMU_DOMAIN_DMA_API))


Nit: probably move above change to patch 14?


Indeed I'm not sure why this one ended up here, good catch!

Thanks,
Robin.


  return 0;
  BUG_ON(!domain->pgsize_bitmap);
diff --git

Re: [PATCH 18/23] iommu: Express DMA strictness via the domain type

2021-07-26 Thread Lu Baolu 

On 2021/7/26 16:27, Robin Murphy wrote:

On 2021-07-24 06:29, Lu Baolu wrote:

Hi Robin,

On 2021/7/22 2:20, Robin Murphy wrote:

Eliminate the iommu_get_dma_strict() indirection and pipe the
information through the domain type from the beginning. Besides
the flow simplification this also has several nice side-effects:

  - Automatically implies strict mode for untrusted devices by
    virtue of their IOMMU_DOMAIN_DMA override.
  - Ensures that we only ends up using flush queues for drivers
    which are aware of them and can actually benefit.


Is this expressed by vendor iommu driver has ops->flush_iotlb_all?


No, it's literally whether ->domain_alloc accepts the DMA_DOMAIN_FQ type 
or not.


Get it. Thank you!

Best regards,
baolu
___
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu

Re: [PATCH 18/23] iommu: Express DMA strictness via the domain type

2021-07-26 Thread Robin Murphy 

On 2021-07-24 06:29, Lu Baolu wrote:

Hi Robin,

On 2021/7/22 2:20, Robin Murphy wrote:

Eliminate the iommu_get_dma_strict() indirection and pipe the
information through the domain type from the beginning. Besides
the flow simplification this also has several nice side-effects:

  - Automatically implies strict mode for untrusted devices by
    virtue of their IOMMU_DOMAIN_DMA override.
  - Ensures that we only ends up using flush queues for drivers
    which are aware of them and can actually benefit.


Is this expressed by vendor iommu driver has ops->flush_iotlb_all?


No, it's literally whether ->domain_alloc accepts the DMA_DOMAIN_FQ type 
or not.



  - Allows us to handle flush queue init failure by falling back
    to strict mode instead of leaving it to possibly blow up later.

Signed-off-by: Robin Murphy 
---
  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c |  2 +-
  drivers/iommu/arm/arm-smmu/arm-smmu.c   |  2 +-
  drivers/iommu/dma-iommu.c   | 10 ++
  drivers/iommu/iommu.c   | 14 --
  include/linux/iommu.h   |  1 -
  5 files changed, 12 insertions(+), 17 deletions(-)

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 fa41026d272e..260b560d0075 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2175,7 +2175,7 @@ static int arm_smmu_domain_finalise(struct 
iommu_domain *domain,

  .iommu_dev    = smmu->dev,
  };
-    if (!iommu_get_dma_strict(domain))
+    if (domain->type == IOMMU_DOMAIN_DMA_FQ)
  pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
  pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain);
diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c 
b/drivers/iommu/arm/arm-smmu/arm-smmu.c

index dbc14c265b15..2c717f3be056 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -765,7 +765,7 @@ static int arm_smmu_init_domain_context(struct 
iommu_domain *domain,

  .iommu_dev    = smmu->dev,
  };
-    if (!iommu_get_dma_strict(domain))
+    if (domain->type == IOMMU_DOMAIN_DMA_FQ)
  pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
  if (smmu->impl && smmu->impl->init_context) {
diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index b1af1ff324c5..a114a7ad88ec 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -363,13 +363,15 @@ static int iommu_dma_init_domain(struct 
iommu_domain *domain, dma_addr_t base,

  init_iova_domain(iovad, 1UL << order, base_pfn);
-    if (!cookie->fq_domain && !dev_is_untrusted(dev) &&
-    domain->ops->flush_iotlb_all && !iommu_get_dma_strict(domain)) {
+    if (domain->type == IOMMU_DOMAIN_DMA_FQ && !cookie->fq_domain &&
+    domain->ops->flush_iotlb_all) {
  if (init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all,
-  iommu_dma_entry_dtor))
+  iommu_dma_entry_dtor)) {
  pr_warn("iova flush queue initialization failed\n");
-    else
+    domain->type = IOMMU_DOMAIN_DMA;
+    } else {
  cookie->fq_domain = domain;
+    }
  }
  return iova_reserve_iommu_regions(dev, domain);
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 8333c334891e..d7eaacae0944 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -135,6 +135,9 @@ static int __init iommu_subsys_init(void)
  }
  }
+    if (!iommu_default_passthrough() && !iommu_dma_strict)
+    iommu_def_domain_type = IOMMU_DOMAIN_DMA_FQ;
+
  pr_info("Default domain type: %s %s\n",
  iommu_domain_type_str(iommu_def_domain_type),
  (iommu_cmd_line & IOMMU_CMD_LINE_DMA_API) ?
@@ -352,15 +355,6 @@ void iommu_set_dma_strict(bool strict)
  iommu_dma_strict = strict;
  }
-bool iommu_get_dma_strict(struct iommu_domain *domain)
-{
-    /* only allow lazy flushing for DMA domains */
-    if (domain->type == IOMMU_DOMAIN_DMA)
-    return iommu_dma_strict;
-    return true;
-}
-EXPORT_SYMBOL_GPL(iommu_get_dma_strict);
-
  static ssize_t iommu_group_attr_show(struct kobject *kobj,
   struct attribute *__attr, char *buf)
  {
@@ -764,7 +758,7 @@ static int 
iommu_create_device_direct_mappings(struct iommu_group *group,

  unsigned long pg_size;
  int ret = 0;
-    if (!domain || domain->type != IOMMU_DOMAIN_DMA)
+    if (!domain || !(domain->type & __IOMMU_DOMAIN_DMA_API))


Nit: probably move above change to patch 14?


Indeed I'm not sure why this one ended up here, good catch!

Thanks,
Robin.


  return 0;
  BUG_ON(!domain->pgsize_bitmap);
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 56519110d43f..557c4c12e2cf 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -484,7 +484,6 @@ int iommu_set_pgtable_quirks(struct iommu_domain 
*domain,

 

Re: [PATCH 18/23] iommu: Express DMA strictness via the domain type

2021-07-23 Thread Lu Baolu 

Hi Robin,

On 2021/7/22 2:20, Robin Murphy wrote:

Eliminate the iommu_get_dma_strict() indirection and pipe the
information through the domain type from the beginning. Besides
the flow simplification this also has several nice side-effects:

  - Automatically implies strict mode for untrusted devices by
virtue of their IOMMU_DOMAIN_DMA override.
  - Ensures that we only ends up using flush queues for drivers
which are aware of them and can actually benefit.


Is this expressed by vendor iommu driver has ops->flush_iotlb_all?


  - Allows us to handle flush queue init failure by falling back
to strict mode instead of leaving it to possibly blow up later.

Signed-off-by: Robin Murphy 
---
  drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c |  2 +-
  drivers/iommu/arm/arm-smmu/arm-smmu.c   |  2 +-
  drivers/iommu/dma-iommu.c   | 10 ++
  drivers/iommu/iommu.c   | 14 --
  include/linux/iommu.h   |  1 -
  5 files changed, 12 insertions(+), 17 deletions(-)

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 fa41026d272e..260b560d0075 100644
--- a/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
+++ b/drivers/iommu/arm/arm-smmu-v3/arm-smmu-v3.c
@@ -2175,7 +2175,7 @@ static int arm_smmu_domain_finalise(struct iommu_domain 
*domain,
.iommu_dev  = smmu->dev,
};
  
-	if (!iommu_get_dma_strict(domain))

+   if (domain->type == IOMMU_DOMAIN_DMA_FQ)
pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
  
  	pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain);

diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c 
b/drivers/iommu/arm/arm-smmu/arm-smmu.c
index dbc14c265b15..2c717f3be056 100644
--- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
+++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
@@ -765,7 +765,7 @@ static int arm_smmu_init_domain_context(struct iommu_domain 
*domain,
.iommu_dev  = smmu->dev,
};
  
-	if (!iommu_get_dma_strict(domain))

+   if (domain->type == IOMMU_DOMAIN_DMA_FQ)
pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
  
  	if (smmu->impl && smmu->impl->init_context) {

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index b1af1ff324c5..a114a7ad88ec 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -363,13 +363,15 @@ static int iommu_dma_init_domain(struct iommu_domain 
*domain, dma_addr_t base,
  
  	init_iova_domain(iovad, 1UL << order, base_pfn);
  
-	if (!cookie->fq_domain && !dev_is_untrusted(dev) &&

-   domain->ops->flush_iotlb_all && !iommu_get_dma_strict(domain)) {
+   if (domain->type == IOMMU_DOMAIN_DMA_FQ && !cookie->fq_domain &&
+   domain->ops->flush_iotlb_all) {
if (init_iova_flush_queue(iovad, iommu_dma_flush_iotlb_all,
- iommu_dma_entry_dtor))
+ iommu_dma_entry_dtor)) {
pr_warn("iova flush queue initialization failed\n");
-   else
+   domain->type = IOMMU_DOMAIN_DMA;
+   } else {
cookie->fq_domain = domain;
+   }
}
  
  	return iova_reserve_iommu_regions(dev, domain);

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 8333c334891e..d7eaacae0944 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -135,6 +135,9 @@ static int __init iommu_subsys_init(void)
}
}
  
+	if (!iommu_default_passthrough() && !iommu_dma_strict)

+   iommu_def_domain_type = IOMMU_DOMAIN_DMA_FQ;
+
pr_info("Default domain type: %s %s\n",
iommu_domain_type_str(iommu_def_domain_type),
(iommu_cmd_line & IOMMU_CMD_LINE_DMA_API) ?
@@ -352,15 +355,6 @@ void iommu_set_dma_strict(bool strict)
iommu_dma_strict = strict;
  }
  
-bool iommu_get_dma_strict(struct iommu_domain *domain)

-{
-   /* only allow lazy flushing for DMA domains */
-   if (domain->type == IOMMU_DOMAIN_DMA)
-   return iommu_dma_strict;
-   return true;
-}
-EXPORT_SYMBOL_GPL(iommu_get_dma_strict);
-
  static ssize_t iommu_group_attr_show(struct kobject *kobj,
 struct attribute *__attr, char *buf)
  {
@@ -764,7 +758,7 @@ static int iommu_create_device_direct_mappings(struct 
iommu_group *group,
unsigned long pg_size;
int ret = 0;
  
-	if (!domain || domain->type != IOMMU_DOMAIN_DMA)

+   if (!domain || !(domain->type & __IOMMU_DOMAIN_DMA_API))


Nit: probably move above change to patch 14?


return 0;
  
  	BUG_ON(!domain->pgsize_bitmap);

diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 56519110d43f..557c4c12e2cf 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -484,7 +484,6 @@ int iommu_set_pgtable_quirks(struct iommu