This callback requests the driver to create only a __IOMMU_DOMAIN_PAGING
domain, so it saves a few lines in a lot of drivers needlessly checking
the type.
More critically, this allows us to sweep out all the
IOMMU_DOMAIN_UNMANAGED and IOMMU_DOMAIN_DMA checks from a lot of the
drivers, simplifying what is going on in the code and ultimately removing
the now-unused special cases in drivers where they did not support
IOMMU_DOMAIN_DMA.
domain_alloc_paging() should return a struct iommu_domain that is
functionally compatible with ARM_DMA_USE_IOMMU, dma-iommu.c and iommufd.
Be forwards looking and pass in a 'struct device *' argument. We can
provide this when allocating the default_domain. No drivers will look at
this.
Signed-off-by: Jason Gunthorpe <j...@nvidia.com>
---
drivers/iommu/iommu.c | 18 +++++++++++++++---
include/linux/iommu.h | 3 +++
2 files changed, 18 insertions(+), 3 deletions(-)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index c4cac1dcf80610..15aa51c356bd74 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1995,14 +1995,25 @@ void iommu_set_fault_handler(struct iommu_domain
*domain,
EXPORT_SYMBOL_GPL(iommu_set_fault_handler);
static struct iommu_domain *__iommu_domain_alloc(const struct iommu_ops *ops,
+ struct device *dev,
unsigned int type)
{
struct iommu_domain *domain;
if (type == IOMMU_DOMAIN_IDENTITY && ops->identity_domain)
return ops->identity_domain;
+ else if ((type == IOMMU_DOMAIN_UNMANAGED || type == IOMMU_DOMAIN_DMA) &&
+ ops->domain_alloc_paging) {
+ /*
+ * For now exclude DMA_FQ since it is still a driver policy
+ * decision through domain_alloc() if we can use FQ mode.
+ */
+ domain = ops->domain_alloc_paging(dev);
+ } else if (ops->domain_alloc)
+ domain = ops->domain_alloc(type);
+ else
+ return NULL;
- domain = ops->domain_alloc(type);
if (!domain)
return NULL;
@@ -2033,14 +2044,15 @@ __iommu_group_domain_alloc(struct iommu_group *group,
unsigned int type)
lockdep_assert_held(&group->mutex);
- return __iommu_domain_alloc(dev_iommu_ops(dev), type);
+ return __iommu_domain_alloc(dev_iommu_ops(dev), dev, type);
}
struct iommu_domain *iommu_domain_alloc(const struct bus_type *bus)
{
if (bus == NULL || bus->iommu_ops == NULL)
return NULL;
- return __iommu_domain_alloc(bus->iommu_ops, IOMMU_DOMAIN_UNMANAGED);
+ return __iommu_domain_alloc(bus->iommu_ops, NULL,
+ IOMMU_DOMAIN_UNMANAGED);
}
EXPORT_SYMBOL_GPL(iommu_domain_alloc);
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index 387746f8273c99..18b0df42cc80d1 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -227,6 +227,8 @@ struct iommu_iotlb_gather {
* struct iommu_ops - iommu ops and capabilities
* @capable: check capability
* @domain_alloc: allocate iommu domain
+ * @domain_alloc_paging: Allocate an iommu_domain that can be used for
+ * UNMANAGED, DMA, and DMA_FQ domain types.
* @probe_device: Add device to iommu driver handling
* @release_device: Remove device from iommu driver handling
* @probe_finalize: Do final setup work after the device is added to an IOMMU
@@ -258,6 +260,7 @@ struct iommu_ops {
/* Domain allocation and freeing by the iommu driver */
struct iommu_domain *(*domain_alloc)(unsigned iommu_domain_type);
+ struct iommu_domain *(*domain_alloc_paging)(struct device *dev);
struct iommu_device *(*probe_device)(struct device *dev);
void (*release_device)(struct device *dev);
--
2.40.1
