[PATCH 18/20] iommu: Add ops->domain_alloc_paging()
Jason Gunthorpe
jgg at nvidia.com
Mon May 1 11:03:02 PDT 2023
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 <jgg at nvidia.com>
---
drivers/iommu/iommu.c | 40 ++++++++++++++++++++++++----------------
include/linux/iommu.h | 2 ++
2 files changed, 26 insertions(+), 16 deletions(-)
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index f20a031e2910b2..fee417df8f195d 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -93,6 +93,7 @@ static int iommu_bus_notifier(struct notifier_block *nb,
unsigned long action, void *data);
static void iommu_release_device(struct device *dev);
static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,
+ struct device *dev,
unsigned type);
static int __iommu_attach_device(struct iommu_domain *domain,
struct device *dev);
@@ -1618,12 +1619,12 @@ static int iommu_get_def_domain_type(struct device *dev)
}
static struct iommu_domain *
-__iommu_group_alloc_default_domain(struct bus_type *bus,
+__iommu_group_alloc_default_domain(struct group_device *gdev,
struct iommu_group *group, int req_type)
{
if (group->default_domain && group->default_domain->type == req_type)
return group->default_domain;
- return __iommu_domain_alloc(bus, req_type);
+ return __iommu_domain_alloc(gdev->dev->bus, gdev->dev, req_type);
}
/*
@@ -1633,9 +1634,9 @@ __iommu_group_alloc_default_domain(struct bus_type *bus,
static struct iommu_domain *
iommu_group_alloc_default_domain(struct iommu_group *group, int req_type)
{
- struct bus_type *bus =
- list_first_entry(&group->devices, struct group_device, list)
- ->dev->bus;
+ struct group_device *gdev =
+ list_first_entry(&group->devices, struct group_device, list);
+ const struct iommu_ops *ops = dev_iommu_ops(gdev->dev);
struct iommu_domain *dom;
lockdep_assert_held(&group->mutex);
@@ -1645,14 +1646,15 @@ iommu_group_alloc_default_domain(struct iommu_group *group, int req_type)
* domain. This should always be either an IDENTITY or PLATFORM domain.
* Do not use in new drivers.
*/
- if (bus->iommu_ops->default_domain) {
+ if (ops->default_domain) {
if (req_type)
return ERR_PTR(-EINVAL);
- return bus->iommu_ops->default_domain;
+ return ops->default_domain;
}
if (req_type)
- return __iommu_group_alloc_default_domain(bus, group, req_type);
+ return __iommu_group_alloc_default_domain(gdev, group,
+ req_type);
/*
* If ARM32 CONFIG_ARM_DMA_USE_IOMMU is enabled and the driver doesn't
@@ -1665,18 +1667,19 @@ iommu_group_alloc_default_domain(struct iommu_group *group, int req_type)
IS_ENABLED(CONFIG_IOMMU_DMA)));
return __iommu_group_alloc_default_domain(
- bus, group, IOMMU_DOMAIN_IDENTITY);
+ gdev, group, IOMMU_DOMAIN_IDENTITY);
}
/* The driver gave no guidance on what type to use, try the default */
- dom = __iommu_group_alloc_default_domain(bus, group, iommu_def_domain_type);
+ dom = __iommu_group_alloc_default_domain(gdev, group,
+ iommu_def_domain_type);
if (dom)
return dom;
/* Otherwise IDENTITY and DMA_FQ defaults will try DMA */
if (iommu_def_domain_type == IOMMU_DOMAIN_DMA)
return NULL;
- dom = __iommu_group_alloc_default_domain(bus, group, IOMMU_DOMAIN_DMA);
+ dom = __iommu_group_alloc_default_domain(gdev, group, IOMMU_DOMAIN_DMA);
if (!dom)
return NULL;
@@ -1930,6 +1933,7 @@ void iommu_set_fault_handler(struct iommu_domain *domain,
EXPORT_SYMBOL_GPL(iommu_set_fault_handler);
static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,
+ struct device *dev,
unsigned type)
{
struct iommu_domain *domain;
@@ -1940,7 +1944,11 @@ static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,
if (type == IOMMU_DOMAIN_IDENTITY && bus->iommu_ops->identity_domain)
return bus->iommu_ops->identity_domain;
- domain = bus->iommu_ops->domain_alloc(type);
+ if ((type == IOMMU_DOMAIN_UNMANAGED || type == IOMMU_DOMAIN_DMA) &&
+ bus->iommu_ops->domain_alloc_paging)
+ domain = bus->iommu_ops->domain_alloc_paging(dev);
+ else
+ domain = bus->iommu_ops->domain_alloc(type);
if (!domain)
return NULL;
@@ -1964,7 +1972,7 @@ static struct iommu_domain *__iommu_domain_alloc(struct bus_type *bus,
struct iommu_domain *iommu_domain_alloc(struct bus_type *bus)
{
- return __iommu_domain_alloc(bus, IOMMU_DOMAIN_UNMANAGED);
+ return __iommu_domain_alloc(bus, NULL, IOMMU_DOMAIN_UNMANAGED);
}
EXPORT_SYMBOL_GPL(iommu_domain_alloc);
@@ -3079,15 +3087,15 @@ static int __iommu_group_alloc_blocking_domain(struct iommu_group *group)
if (group->blocking_domain)
return 0;
- group->blocking_domain =
- __iommu_domain_alloc(dev->dev->bus, IOMMU_DOMAIN_BLOCKED);
+ group->blocking_domain = __iommu_domain_alloc(dev->dev->bus, dev->dev,
+ IOMMU_DOMAIN_BLOCKED);
if (!group->blocking_domain) {
/*
* For drivers that do not yet understand IOMMU_DOMAIN_BLOCKED
* create an empty domain instead.
*/
group->blocking_domain = __iommu_domain_alloc(
- dev->dev->bus, IOMMU_DOMAIN_UNMANAGED);
+ dev->dev->bus, dev->dev, IOMMU_DOMAIN_UNMANAGED);
if (!group->blocking_domain)
return -EINVAL;
}
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index f6a28ab78e607e..cc9aff2d213eec 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -227,6 +227,7 @@ 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_UNMANAGED
* @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 +259,7 @@ 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);
--
2.40.0
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