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iommu: Allow an IDENTITY domain as the default_domain in ARM32

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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 <steven.price@arm.com>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Tested-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/9-v8-81230027b2fa+9d-iommu_all_defdom_jgg@nvidia.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
This commit is contained in:
Jason Gunthorpe 2023-09-13 10:43:42 -03:00 committed by Joerg Roedel
parent 59ddce4418
commit e98befd010
3 changed files with 20 additions and 23 deletions
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21
drivers/iommu/iommu.c
View File

@ -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) {

12
drivers/iommu/mtk_iommu_v1.c
View File

@ -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;
}
static int mtk_iommu_v1_def_domain_type(struct device *dev)
{
return IOMMU_DOMAIN_IDENTITY;
}
static struct iommu_device *mtk_iommu_v1_probe_device(struct device *dev)
{
struct iommu_fwspec *fwspec = dev_iommu_fwspec_get(dev);
@ -599,10 +589,8 @@ static const struct iommu_ops mtk_iommu_v1_ops = {
.probe_device = mtk_iommu_v1_probe_device,
.probe_finalize = mtk_iommu_v1_probe_finalize,
.release_device = mtk_iommu_v1_release_device,
.def_domain_type = mtk_iommu_v1_def_domain_type,
.device_group = generic_device_group,
.pgsize_bitmap = MT2701_IOMMU_PAGE_SIZE,
.set_platform_dma_ops = mtk_iommu_v1_set_platform_dma,
.owner = THIS_MODULE,
.default_domain_ops = &(const struct iommu_domain_ops) {
.attach_dev = mtk_iommu_v1_attach_device,

10
drivers/iommu/rockchip-iommu.c
View File

@ -998,13 +998,6 @@ static struct iommu_domain rk_identity_domain = {
.ops = &rk_identity_ops,
};
#ifdef CONFIG_ARM
static void rk_iommu_set_platform_dma(struct device *dev)
{
WARN_ON(rk_iommu_identity_attach(&rk_identity_domain, dev));
}
#endif
static int rk_iommu_attach_device(struct iommu_domain *domain,
struct device *dev)
{
@ -1183,9 +1176,6 @@ static const struct iommu_ops rk_iommu_ops = {
.probe_device = rk_iommu_probe_device,
.release_device = rk_iommu_release_device,
.device_group = rk_iommu_device_group,
#ifdef CONFIG_ARM
.set_platform_dma_ops = rk_iommu_set_platform_dma,
#endif
.pgsize_bitmap = RK_IOMMU_PGSIZE_BITMAP,
.of_xlate = rk_iommu_of_xlate,
.default_domain_ops = &(const struct iommu_domain_ops) {