Driver can call the iommufd_viommu_find_device() to find a device pointer using its per-viommu virtual ID. The returned device must be protected by the pair of iommufd_viommu_lock/unlock_vdev_id() function.
Put these three functions into a new viommu_api file, to build it with the IOMMUFD_DRIVER config.
Signed-off-by: Nicolin Chen nicolinc@nvidia.com --- drivers/iommu/iommufd/Makefile | 2 +- drivers/iommu/iommufd/viommu_api.c | 39 ++++++++++++++++++++++++++++++ include/linux/iommufd.h | 16 ++++++++++++ 3 files changed, 56 insertions(+), 1 deletion(-) create mode 100644 drivers/iommu/iommufd/viommu_api.c
diff --git a/drivers/iommu/iommufd/Makefile b/drivers/iommu/iommufd/Makefile index df490e836b30..288ef3e895e3 100644 --- a/drivers/iommu/iommufd/Makefile +++ b/drivers/iommu/iommufd/Makefile @@ -13,4 +13,4 @@ iommufd-y := \ iommufd-$(CONFIG_IOMMUFD_TEST) += selftest.o
obj-$(CONFIG_IOMMUFD) += iommufd.o -obj-$(CONFIG_IOMMUFD_DRIVER) += iova_bitmap.o +obj-$(CONFIG_IOMMUFD_DRIVER) += iova_bitmap.o viommu_api.o diff --git a/drivers/iommu/iommufd/viommu_api.c b/drivers/iommu/iommufd/viommu_api.c new file mode 100644 index 000000000000..e0ee592ce834 --- /dev/null +++ b/drivers/iommu/iommufd/viommu_api.c @@ -0,0 +1,39 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2024, NVIDIA CORPORATION & AFFILIATES + */ + +#include "iommufd_private.h" + +void iommufd_viommu_lock_vdev_id(struct iommufd_viommu *viommu) +{ + down_read(&viommu->vdev_ids_rwsem); +} +EXPORT_SYMBOL_NS_GPL(iommufd_viommu_lock_vdev_id, IOMMUFD); + +void iommufd_viommu_unlock_vdev_id(struct iommufd_viommu *viommu) +{ + up_read(&viommu->vdev_ids_rwsem); +} +EXPORT_SYMBOL_NS_GPL(iommufd_viommu_unlock_vdev_id, IOMMUFD); + +/* + * Find a device attached to an VIOMMU object using a virtual device ID that was + * set via an IOMMUFD_CMD_VIOMMU_SET_VDEV_ID. Callers of this function must call + * iommufd_viommu_lock_vdev_id() prior and iommufd_viommu_unlock_vdev_id() after + * + * Return device or NULL. + */ +struct device *iommufd_viommu_find_device(struct iommufd_viommu *viommu, u64 id) +{ + struct iommufd_vdev_id *vdev_id; + + lockdep_assert_held(&viommu->vdev_ids_rwsem); + + xa_lock(&viommu->vdev_ids); + vdev_id = xa_load(&viommu->vdev_ids, (unsigned long)id); + xa_unlock(&viommu->vdev_ids); + if (!vdev_id || vdev_id->id != id) + return NULL; + return vdev_id->idev->dev; +} +EXPORT_SYMBOL_NS_GPL(iommufd_viommu_find_device, IOMMUFD); diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h index 85291b346348..364f151d281d 100644 --- a/include/linux/iommufd.h +++ b/include/linux/iommufd.h @@ -89,6 +89,9 @@ int iommufd_access_rw(struct iommufd_access *access, unsigned long iova, int iommufd_vfio_compat_ioas_get_id(struct iommufd_ctx *ictx, u32 *out_ioas_id); int iommufd_vfio_compat_ioas_create(struct iommufd_ctx *ictx); int iommufd_vfio_compat_set_no_iommu(struct iommufd_ctx *ictx); +void iommufd_viommu_lock_vdev_id(struct iommufd_viommu *viommu); +void iommufd_viommu_unlock_vdev_id(struct iommufd_viommu *viommu); +struct device *iommufd_viommu_find_device(struct iommufd_viommu *viommu, u64 id); #else /* !CONFIG_IOMMUFD */ static inline struct iommufd_ctx *iommufd_ctx_from_file(struct file *file) { @@ -129,5 +132,18 @@ static inline int iommufd_vfio_compat_set_no_iommu(struct iommufd_ctx *ictx) { return -EOPNOTSUPP; } + +void iommufd_viommu_lock_vdev_id(struct iommufd_viommu *viommu) +{ +} + +void iommufd_viommu_unlock_vdev_id(struct iommufd_viommu *viommu) +{ +} + +struct device *iommufd_viommu_find_device(struct iommufd_viommu *viommu, u64 id) +{ + return NULL; +} #endif /* CONFIG_IOMMUFD */ #endif