diff mbox series

[v5,05/18] iommufd: Add a flag to enforce dirty tracking on attach

Message ID 20231020222804.21850-6-joao.m.martins@oracle.com (mailing list archive)
State New, archived
Headers show
Series IOMMUFD Dirty Tracking | expand

Commit Message

Joao Martins Oct. 20, 2023, 10:27 p.m. UTC 
Throughout IOMMU domain lifetime that wants to use dirty tracking, some
guarantees are needed such that any device attached to the iommu_domain
supports dirty tracking.

The idea is to handle a case where IOMMU in the system are assymetric
feature-wise and thus the capability may not be supported for all devices.
The enforcement is done by adding a flag into HWPT_ALLOC namely:

	IOMMU_HWPT_ALLOC_DIRTY_TRACKING

.. Passed in HWPT_ALLOC ioctl() flags. The enforcement is done by creating
a iommu_domain via domain_alloc_user() and validating the requested flags
with what the device IOMMU supports (and failing accordingly) advertised).
Advertising the new IOMMU domain feature flag requires that the individual
iommu driver capability is supported when a future device attachment
happens.

Link: https://lore.kernel.org/kvm/20220721142421.GB4609@nvidia.com/
Signed-off-by: Joao Martins <joao.m.martins@oracle.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
---
 drivers/iommu/iommufd/hw_pagetable.c | 4 +++-
 include/uapi/linux/iommufd.h         | 3 +++
 2 files changed, 6 insertions(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/drivers/iommu/iommufd/hw_pagetable.c b/drivers/iommu/iommufd/hw_pagetable.c
index 8b3d2875d642..d4a714212e0b 100644
--- a/drivers/iommu/iommufd/hw_pagetable.c
+++ b/drivers/iommu/iommufd/hw_pagetable.c
@@ -157,7 +157,9 @@  int iommufd_hwpt_alloc(struct iommufd_ucmd *ucmd)
 	struct iommufd_ioas *ioas;
 	int rc;
 
-	if ((cmd->flags & (~IOMMU_HWPT_ALLOC_NEST_PARENT)) || cmd->__reserved)
+	if ((cmd->flags &
+	    ~(IOMMU_HWPT_ALLOC_NEST_PARENT|IOMMU_HWPT_ALLOC_DIRTY_TRACKING)) ||
+	    cmd->__reserved)
 		return -EOPNOTSUPP;
 
 	idev = iommufd_get_device(ucmd, cmd->dev_id);
diff --git a/include/uapi/linux/iommufd.h b/include/uapi/linux/iommufd.h
index 4a7c5c8fdbb4..793039634687 100644
--- a/include/uapi/linux/iommufd.h
+++ b/include/uapi/linux/iommufd.h
@@ -352,9 +352,12 @@  struct iommu_vfio_ioas {
  * @IOMMU_HWPT_ALLOC_NEST_PARENT: If set, allocate a domain which can serve
  *                                as the parent domain in the nesting
  *                                configuration.
+ * @IOMMU_HWPT_ALLOC_DIRTY_TRACKING: Dirty tracking support for device IOMMU is
+ *                                   enforced on device attachment
  */
 enum iommufd_hwpt_alloc_flags {
 	IOMMU_HWPT_ALLOC_NEST_PARENT = 1 << 0,
+	IOMMU_HWPT_ALLOC_DIRTY_TRACKING = 1 << 1,
 };
 
 /**