For vIOMMU passing through HW resources to user space (VMs), add an mmap infrastructure to map a region of hardware MMIO pages. The addr and size should be given previously via a prior IOMMU_VIOMMU_ALLOC ioctl in some output fields of the structure.
Maintain an mt_mmap per ictx for validations. And give IOMMU drivers a pair of helpers to add and delete mmap regions onto the mt_mmap.
Signed-off-by: Nicolin Chen nicolinc@nvidia.com --- drivers/iommu/iommufd/iommufd_private.h | 9 ++++++ include/linux/iommufd.h | 15 ++++++++++ drivers/iommu/iommufd/driver.c | 40 +++++++++++++++++++++++++ drivers/iommu/iommufd/main.c | 35 ++++++++++++++++++++++ 4 files changed, 99 insertions(+)
diff --git a/drivers/iommu/iommufd/iommufd_private.h b/drivers/iommu/iommufd/iommufd_private.h index da35ffcc212b..5be0248966aa 100644 --- a/drivers/iommu/iommufd/iommufd_private.h +++ b/drivers/iommu/iommufd/iommufd_private.h @@ -7,6 +7,7 @@ #include <linux/iommu.h> #include <linux/iommufd.h> #include <linux/iova_bitmap.h> +#include <linux/maple_tree.h> #include <linux/rwsem.h> #include <linux/uaccess.h> #include <linux/xarray.h> @@ -44,6 +45,7 @@ struct iommufd_ctx { struct xarray groups; wait_queue_head_t destroy_wait; struct rw_semaphore ioas_creation_lock; + struct maple_tree mt_mmap;
struct mutex sw_msi_lock; struct list_head sw_msi_list; @@ -55,6 +57,13 @@ struct iommufd_ctx { struct iommufd_ioas *vfio_ioas; };
+/* Entry for iommufd_ctx::mt_mmap */ +struct iommufd_mmap { + unsigned long pfn_start; + unsigned long pfn_end; + bool is_io; +}; + /* * The IOVA to PFN map. The map automatically copies the PFNs into multiple * domains and permits sharing of PFNs between io_pagetable instances. This diff --git a/include/linux/iommufd.h b/include/linux/iommufd.h index 4118eaece1a5..e9394e20c4dd 100644 --- a/include/linux/iommufd.h +++ b/include/linux/iommufd.h @@ -226,6 +226,9 @@ struct iommufd_object *_iommufd_object_alloc(struct iommufd_ctx *ictx, size_t size, enum iommufd_object_type type); void iommufd_object_abort(struct iommufd_ctx *ictx, struct iommufd_object *obj); +int iommufd_ctx_alloc_mmap(struct iommufd_ctx *ictx, phys_addr_t base, + size_t size, bool is_io, unsigned long *immap_id); +void iommufd_ctx_free_mmap(struct iommufd_ctx *ictx, unsigned long immap_id); struct device *iommufd_viommu_find_dev(struct iommufd_viommu *viommu, unsigned long vdev_id); int iommufd_viommu_get_vdev_id(struct iommufd_viommu *viommu, @@ -246,6 +249,18 @@ static inline void iommufd_object_abort(struct iommufd_ctx *ictx, { }
+static inline int iommufd_ctx_alloc_mmap(struct iommufd_ctx *ictx, + phys_addr_t base, size_t size, + bool is_io, unsigned long *immap_id) +{ + return -EOPNOTSUPP; +} + +static inline void iommufd_ctx_free_mmap(struct iommufd_ctx *ictx, + unsigned long immap_id) +{ +} + static inline struct device * iommufd_viommu_find_dev(struct iommufd_viommu *viommu, unsigned long vdev_id) { diff --git a/drivers/iommu/iommufd/driver.c b/drivers/iommu/iommufd/driver.c index 7980a09761c2..abe0bdc1e9a3 100644 --- a/drivers/iommu/iommufd/driver.c +++ b/drivers/iommu/iommufd/driver.c @@ -50,6 +50,46 @@ void iommufd_object_abort(struct iommufd_ctx *ictx, struct iommufd_object *obj) } EXPORT_SYMBOL_NS_GPL(iommufd_object_abort, "IOMMUFD");
+/* Driver should report the immap_id to user space for mmap() syscalls */ +int iommufd_ctx_alloc_mmap(struct iommufd_ctx *ictx, phys_addr_t base, + size_t size, bool is_io, unsigned long *immap_id) +{ + struct iommufd_mmap *immap; + int rc; + + if (WARN_ON_ONCE(!immap_id)) + return -EINVAL; + if (base & ~PAGE_MASK) + return -EINVAL; + if (!size || size & ~PAGE_MASK) + return -EINVAL; + + immap = kzalloc(sizeof(*immap), GFP_KERNEL); + if (!immap) + return -ENOMEM; + immap->pfn_start = base >> PAGE_SHIFT; + immap->pfn_end = immap->pfn_start + (size >> PAGE_SHIFT) - 1; + immap->is_io = is_io; + + rc = mtree_alloc_range(&ictx->mt_mmap, immap_id, immap, sizeof(immap), + 0, LONG_MAX >> PAGE_SHIFT, GFP_KERNEL); + if (rc < 0) { + kfree(immap); + return rc; + } + + /* mmap() syscall would right-shift the immap_id to vma->vm_pgoff */ + *immap_id <<= PAGE_SHIFT; + return 0; +} +EXPORT_SYMBOL_NS_GPL(iommufd_ctx_alloc_mmap, "IOMMUFD"); + +void iommufd_ctx_free_mmap(struct iommufd_ctx *ictx, unsigned long immap_id) +{ + kfree(mtree_erase(&ictx->mt_mmap, immap_id >> PAGE_SHIFT)); +} +EXPORT_SYMBOL_NS_GPL(iommufd_ctx_free_mmap, "IOMMUFD"); + /* Caller should xa_lock(&viommu->vdevs) to protect the return value */ struct device *iommufd_viommu_find_dev(struct iommufd_viommu *viommu, unsigned long vdev_id) diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c index 27473aff150f..d3101c76fcb8 100644 --- a/drivers/iommu/iommufd/main.c +++ b/drivers/iommu/iommufd/main.c @@ -213,6 +213,7 @@ static int iommufd_fops_open(struct inode *inode, struct file *filp) xa_init_flags(&ictx->objects, XA_FLAGS_ALLOC1 | XA_FLAGS_ACCOUNT); xa_init(&ictx->groups); ictx->file = filp; + mt_init_flags(&ictx->mt_mmap, MT_FLAGS_ALLOC_RANGE); init_waitqueue_head(&ictx->destroy_wait); mutex_init(&ictx->sw_msi_lock); INIT_LIST_HEAD(&ictx->sw_msi_list); @@ -410,11 +411,45 @@ static long iommufd_fops_ioctl(struct file *filp, unsigned int cmd, return ret; }
+/* + * The pfn and size carried in @vma from the user space mmap call should be + * previously given to user space via a prior ioctl output. + */ +static int iommufd_fops_mmap(struct file *filp, struct vm_area_struct *vma) +{ + struct iommufd_ctx *ictx = filp->private_data; + size_t size = vma->vm_end - vma->vm_start; + struct iommufd_mmap *immap; + + if (size & ~PAGE_MASK) + return -EINVAL; + if (!(vma->vm_flags & VM_SHARED)) + return -EINVAL; + if (vma->vm_flags & VM_EXEC) + return -EPERM; + + /* vm_pgoff carries an index of an mtree entry/immap */ + immap = mtree_load(&ictx->mt_mmap, vma->vm_pgoff); + if (!immap) + return -EINVAL; + if (size >> PAGE_SHIFT > immap->pfn_end - immap->pfn_start + 1) + return -EINVAL; + + vma->vm_pgoff = 0; + vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot); + vm_flags_set(vma, VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP); + if (immap->is_io) + vm_flags_set(vma, VM_IO); + return remap_pfn_range(vma, vma->vm_start, immap->pfn_start, size, + vma->vm_page_prot); +} + static const struct file_operations iommufd_fops = { .owner = THIS_MODULE, .open = iommufd_fops_open, .release = iommufd_fops_release, .unlocked_ioctl = iommufd_fops_ioctl, + .mmap = iommufd_fops_mmap, };
/**