[PATCH v7 09/24] iommu: Allow an IDENTITY domain as the default_domain in ARM32

2023-08-23 Thread Jason Gunthorpe
Even though dma-iommu.c and CONFIG_ARM_DMA_USE_IOMMU do approximately the
same stuff, the way they relate to the IOMMU core is quiet different.

dma-iommu.c expects the core code to setup an UNMANAGED domain (of type
IOMMU_DOMAIN_DMA) and then configures itself to use that domain. This
becomes the default_domain for the group.

ARM_DMA_USE_IOMMU does not use the default_domain, instead it directly
allocates an UNMANAGED domain and operates it just like an external
driver. In this case group->default_domain is NULL.

If the driver provides a global static identity_domain then automatically
use it as the default_domain when in ARM_DMA_USE_IOMMU mode.

This allows drivers that implemented default_domain == NULL as an IDENTITY
translation to trivially get a properly labeled non-NULL default_domain on
ARM32 configs.

With this arrangment when ARM_DMA_USE_IOMMU wants to disconnect from the
device the normal detach_domain flow will restore the IDENTITY domain as
the default domain. Overall this makes attach_dev() of the IDENTITY domain
called in the same places as detach_dev().

This effectively migrates these drivers to default_domain mode. For
drivers that support ARM64 they will gain support for the IDENTITY
translation mode for the dma_api and behave in a uniform way.

Drivers use this by setting ops->identity_domain to a static singleton
iommu_domain that implements the identity attach. If the core detects
ARM_DMA_USE_IOMMU mode then it automatically attaches the IDENTITY domain
during probe.

Drivers can continue to prevent the use of DMA translation by returning
IOMMU_DOMAIN_IDENTITY from def_domain_type, this will completely prevent
IOMMU_DMA from running but will not impact ARM_DMA_USE_IOMMU.

This allows removing the set_platform_dma_ops() from every remaining
driver.

Remove the set_platform_dma_ops from rockchip and mkt_v1 as all it does
is set an existing global static identity domain. mkt_v1 does not support
IOMMU_DOMAIN_DMA and it does not compile on ARM64 so this transformation
is safe.

Tested-by: Steven Price 
Tested-by: Marek Szyprowski 
Tested-by: Nicolin Chen 
Reviewed-by: Lu Baolu 
Signed-off-by: Jason Gunthorpe 
---
 drivers/iommu/iommu.c  | 21 -
 drivers/iommu/mtk_iommu_v1.c   | 12 
 drivers/iommu/rockchip-iommu.c | 10 --
 3 files changed, 20 insertions(+), 23 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index bdeeb574d9495c..5fb25bcbc42f76 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1865,17 +1865,36 @@ static int iommu_get_def_domain_type(struct iommu_group 
*group,
 static int iommu_get_default_domain_type(struct iommu_group *group,
 int target_type)
 {
+   const struct iommu_ops *ops = group_iommu_ops(group);
struct device *untrusted = NULL;
struct group_device *gdev;
int driver_type = 0;
 
lockdep_assert_held(&group->mutex);
+
+   /*
+* ARM32 drivers supporting CONFIG_ARM_DMA_USE_IOMMU can declare an
+* identity_domain and it will automatically become their default
+* domain. Later on ARM_DMA_USE_IOMMU will install its UNMANAGED domain.
+* Override the selection to IDENTITY if we are sure the driver supports
+* it.
+*/
+   if (IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU) && ops->identity_domain)
+   driver_type = IOMMU_DOMAIN_IDENTITY;
+
for_each_group_device(group, gdev) {
driver_type = iommu_get_def_domain_type(group, gdev->dev,
driver_type);
 
-   if (dev_is_pci(gdev->dev) && to_pci_dev(gdev->dev)->untrusted)
+   if (dev_is_pci(gdev->dev) && to_pci_dev(gdev->dev)->untrusted) {
+   /*
+* No ARM32 using systems will set untrusted, it cannot
+* work.
+*/
+   if (WARN_ON(IS_ENABLED(CONFIG_ARM_DMA_USE_IOMMU)))
+   return -1;
untrusted = gdev->dev;
+   }
}
 
if (untrusted) {
diff --git a/drivers/iommu/mtk_iommu_v1.c b/drivers/iommu/mtk_iommu_v1.c
index cc3e7d53d33ad9..7c0c1d50df5f75 100644
--- a/drivers/iommu/mtk_iommu_v1.c
+++ b/drivers/iommu/mtk_iommu_v1.c
@@ -337,11 +337,6 @@ static struct iommu_domain mtk_iommu_v1_identity_domain = {
.ops = &mtk_iommu_v1_identity_ops,
 };
 
-static void mtk_iommu_v1_set_platform_dma(struct device *dev)
-{
-   mtk_iommu_v1_identity_attach(&mtk_iommu_v1_identity_domain, dev);
-}
-
 static int mtk_iommu_v1_map(struct iommu_domain *domain, unsigned long iova,
phys_addr_t paddr, size_t pgsize, size_t pgcount,
int prot, gfp_t gfp, size_t *mapped)
@@ -457,11 +452,6 @@ static int mtk_iommu_v1_create_mapping(struct device *dev, 
struct of_phandle_arg
return 0;
 }
 

Re: [PATCH v7 09/24] iommu: Allow an IDENTITY domain as the default_domain in ARM32

2023-08-28 Thread Jerry Snitselaar
On Wed, Aug 23, 2023 at 01:47:23PM -0300, Jason Gunthorpe wrote:
> Even though dma-iommu.c and CONFIG_ARM_DMA_USE_IOMMU do approximately the
> same stuff, the way they relate to the IOMMU core is quiet different.
> 
> dma-iommu.c expects the core code to setup an UNMANAGED domain (of type
> IOMMU_DOMAIN_DMA) and then configures itself to use that domain. This
> becomes the default_domain for the group.
> 
> ARM_DMA_USE_IOMMU does not use the default_domain, instead it directly
> allocates an UNMANAGED domain and operates it just like an external
> driver. In this case group->default_domain is NULL.
> 
> If the driver provides a global static identity_domain then automatically
> use it as the default_domain when in ARM_DMA_USE_IOMMU mode.
> 
> This allows drivers that implemented default_domain == NULL as an IDENTITY
> translation to trivially get a properly labeled non-NULL default_domain on
> ARM32 configs.
> 
> With this arrangment when ARM_DMA_USE_IOMMU wants to disconnect from the
> device the normal detach_domain flow will restore the IDENTITY domain as
> the default domain. Overall this makes attach_dev() of the IDENTITY domain
> called in the same places as detach_dev().
> 
> This effectively migrates these drivers to default_domain mode. For
> drivers that support ARM64 they will gain support for the IDENTITY
> translation mode for the dma_api and behave in a uniform way.
> 
> Drivers use this by setting ops->identity_domain to a static singleton
> iommu_domain that implements the identity attach. If the core detects
> ARM_DMA_USE_IOMMU mode then it automatically attaches the IDENTITY domain
> during probe.
> 
> Drivers can continue to prevent the use of DMA translation by returning
> IOMMU_DOMAIN_IDENTITY from def_domain_type, this will completely prevent
> IOMMU_DMA from running but will not impact ARM_DMA_USE_IOMMU.
> 
> This allows removing the set_platform_dma_ops() from every remaining
> driver.
> 
> Remove the set_platform_dma_ops from rockchip and mkt_v1 as all it does
> is set an existing global static identity domain. mkt_v1 does not support
> IOMMU_DOMAIN_DMA and it does not compile on ARM64 so this transformation
> is safe.
> 
> Tested-by: Steven Price 
> Tested-by: Marek Szyprowski 
> Tested-by: Nicolin Chen 
> Reviewed-by: Lu Baolu 
> Signed-off-by: Jason Gunthorpe 
> ---
>  drivers/iommu/iommu.c  | 21 -
>  drivers/iommu/mtk_iommu_v1.c   | 12 
>  drivers/iommu/rockchip-iommu.c | 10 --
>  3 files changed, 20 insertions(+), 23 deletions(-)
> 

Reviewed-by: Jerry Snitselaar