diff options
| author | Lu Baolu <baolu.lu@linux.intel.com> | 2024-02-12 09:22:23 +0800 |
|---|---|---|
| committer | Joerg Roedel <jroedel@suse.de> | 2024-02-16 15:19:33 +0100 |
| commit | a74c077b9021b36c785095c571336e5b204d3c2d (patch) | |
| tree | 7e33054cae25270ebce39c5549050b1e4a69dbb1 /drivers/iommu/iommu-sva.c | |
| parent | cc7338e9d807e20e60e6720a62956f0e9d46f0f8 (diff) | |
| download | linux-a74c077b9021b36c785095c571336e5b204d3c2d.tar.gz linux-a74c077b9021b36c785095c571336e5b204d3c2d.tar.bz2 linux-a74c077b9021b36c785095c571336e5b204d3c2d.zip | |
iommu: Use refcount for fault data access
The per-device fault data structure stores information about faults
occurring on a device. Its lifetime spans from IOPF enablement to
disablement. Multiple paths, including IOPF reporting, handling, and
responding, may access it concurrently.
Previously, a mutex protected the fault data from use after free. But
this is not performance friendly due to the critical nature of IOPF
handling paths.
Refine this with a refcount-based approach. The fault data pointer is
obtained within an RCU read region with a refcount. The fault data
pointer is returned for usage only when the pointer is valid and a
refcount is successfully obtained. The fault data is freed with
kfree_rcu(), ensuring data is only freed after all RCU critical regions
complete.
An iopf handling work starts once an iopf group is created. The handling
work continues until iommu_page_response() is called to respond to the
iopf and the iopf group is freed. During this time, the device fault
parameter should always be available. Add a pointer to the device fault
parameter in the iopf_group structure and hold the reference until the
iopf_group is freed.
Make iommu_page_response() static as it is only used in io-pgfault.c.
Co-developed-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Tested-by: Yan Zhao <yan.y.zhao@intel.com>
Link: https://lore.kernel.org/r/20240212012227.119381-13-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Diffstat (limited to 'drivers/iommu/iommu-sva.c')
| -rw-r--r-- | drivers/iommu/iommu-sva.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/iommu/iommu-sva.c b/drivers/iommu/iommu-sva.c index 9de878e40413..b51995b4fe90 100644 --- a/drivers/iommu/iommu-sva.c +++ b/drivers/iommu/iommu-sva.c @@ -251,7 +251,7 @@ static void iommu_sva_handle_iopf(struct work_struct *work) static int iommu_sva_iopf_handler(struct iopf_group *group) { - struct iommu_fault_param *fault_param = group->dev->iommu->fault_param; + struct iommu_fault_param *fault_param = group->fault_param; INIT_WORK(&group->work, iommu_sva_handle_iopf); if (!queue_work(fault_param->queue->wq, &group->work)) |