@@ -882,6 +882,10 @@ struct module;
* created once it is bound to the driver.
* @driver: Driver model structure.
* @dynids: List of dynamically added device IDs.
+ * @suppress_auto_claim_dma_owner: Disable auto claiming of kernel DMA owner.
+ * Drivers which don't require DMA or want to manually claim the
+ * owner type (e.g. userspace driver frameworks) could set this
+ * flag.
*/
struct pci_driver {
struct list_head node;
@@ -900,6 +904,7 @@ struct pci_driver {
const struct attribute_group **dev_groups;
struct device_driver driver;
struct pci_dynids dynids;
+ bool suppress_auto_claim_dma_owner;
};
static inline struct pci_driver *to_pci_driver(struct device_driver *drv)
@@ -20,6 +20,7 @@
#include <linux/of_device.h>
#include <linux/acpi.h>
#include <linux/dma-map-ops.h>
+#include <linux/iommu.h>
#include "pci.h"
#include "pcie/portdrv.h"
@@ -1590,9 +1591,16 @@ static int pci_bus_num_vf(struct device *dev)
*/
static int pci_dma_configure(struct device *dev)
{
+ struct pci_driver *driver = to_pci_driver(dev->driver);
struct device *bridge;
int ret = 0;
+ if (!driver->suppress_auto_claim_dma_owner) {
+ ret = iommu_device_set_dma_owner(dev, DMA_OWNER_DMA_API, NULL);
+ if (ret)
+ return ret;
+ }
+
bridge = pci_get_host_bridge_device(to_pci_dev(dev));
if (IS_ENABLED(CONFIG_OF) && bridge->parent &&
@@ -1605,9 +1613,21 @@ static int pci_dma_configure(struct device *dev)
}
pci_put_host_bridge_device(bridge);
+
+ if (ret && !driver->suppress_auto_claim_dma_owner)
+ iommu_device_release_dma_owner(dev, DMA_OWNER_DMA_API);
+
return ret;
}
+static void pci_dma_unconfigure(struct device *dev)
+{
+ struct pci_driver *driver = to_pci_driver(dev->driver);
+
+ if (!driver->suppress_auto_claim_dma_owner)
+ iommu_device_release_dma_owner(dev, DMA_OWNER_DMA_API);
+}
+
struct bus_type pci_bus_type = {
.name = "pci",
.match = pci_bus_match,
@@ -1621,6 +1641,7 @@ struct bus_type pci_bus_type = {
.pm = PCI_PM_OPS_PTR,
.num_vf = pci_bus_num_vf,
.dma_configure = pci_dma_configure,
+ .dma_unconfigure = pci_dma_unconfigure,
};
EXPORT_SYMBOL(pci_bus_type);
Multiple PCI devices may be placed in the same IOMMU group because they cannot be isolated from each other. These devices must either be entirely under kernel control or userspace control, never a mixture. This checks and sets DMA ownership during driver binding, and vice versa, release the ownership during driver unbinding. Driver may set a new flag (suppress_auto_claim_dma_owner) to disable auto claiming DMA_OWNER_DMA_API ownership in the binding process. For instance, the userspace framework drivers (vfio etc.) which need to manually claim DMA_OWNER_PRIVATE_DOMAIN_USER when assigning a device to userspace. Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com> --- include/linux/pci.h | 5 +++++ drivers/pci/pci-driver.c | 21 +++++++++++++++++++++ 2 files changed, 26 insertions(+)