diff options
Diffstat (limited to 'drivers/gpu/drm/drm_pagemap.c')
| -rw-r--r-- | drivers/gpu/drm/drm_pagemap.c | 838 |
1 files changed, 838 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_pagemap.c b/drivers/gpu/drm/drm_pagemap.c new file mode 100644 index 000000000000..1da55322af12 --- /dev/null +++ b/drivers/gpu/drm/drm_pagemap.c @@ -0,0 +1,838 @@ +// SPDX-License-Identifier: GPL-2.0-only OR MIT +/* + * Copyright © 2024-2025 Intel Corporation + */ + +#include <linux/dma-mapping.h> +#include <linux/migrate.h> +#include <linux/pagemap.h> +#include <drm/drm_drv.h> +#include <drm/drm_pagemap.h> + +/** + * DOC: Overview + * + * The DRM pagemap layer is intended to augment the dev_pagemap functionality by + * providing a way to populate a struct mm_struct virtual range with device + * private pages and to provide helpers to abstract device memory allocations, + * to migrate memory back and forth between device memory and system RAM and + * to handle access (and in the future migration) between devices implementing + * a fast interconnect that is not necessarily visible to the rest of the + * system. + * + * Typically the DRM pagemap receives requests from one or more DRM GPU SVM + * instances to populate struct mm_struct virtual ranges with memory, and the + * migration is best effort only and may thus fail. The implementation should + * also handle device unbinding by blocking (return an -ENODEV) error for new + * population requests and after that migrate all device pages to system ram. + */ + +/** + * DOC: Migration + * + * Migration granularity typically follows the GPU SVM range requests, but + * if there are clashes, due to races or due to the fact that multiple GPU + * SVM instances have different views of the ranges used, and because of that + * parts of a requested range is already present in the requested device memory, + * the implementation has a variety of options. It can fail and it can choose + * to populate only the part of the range that isn't already in device memory, + * and it can evict the range to system before trying to migrate. Ideally an + * implementation would just try to migrate the missing part of the range and + * allocate just enough memory to do so. + * + * When migrating to system memory as a response to a cpu fault or a device + * memory eviction request, currently a full device memory allocation is + * migrated back to system. Moving forward this might need improvement for + * situations where a single page needs bouncing between system memory and + * device memory due to, for example, atomic operations. + * + * Key DRM pagemap components: + * + * - Device Memory Allocations: + * Embedded structure containing enough information for the drm_pagemap to + * migrate to / from device memory. + * + * - Device Memory Operations: + * Define the interface for driver-specific device memory operations + * release memory, populate pfns, and copy to / from device memory. + */ + +/** + * struct drm_pagemap_zdd - GPU SVM zone device data + * + * @refcount: Reference count for the zdd + * @devmem_allocation: device memory allocation + * @device_private_page_owner: Device private pages owner + * + * This structure serves as a generic wrapper installed in + * page->zone_device_data. It provides infrastructure for looking up a device + * memory allocation upon CPU page fault and asynchronously releasing device + * memory once the CPU has no page references. Asynchronous release is useful + * because CPU page references can be dropped in IRQ contexts, while releasing + * device memory likely requires sleeping locks. + */ +struct drm_pagemap_zdd { + struct kref refcount; + struct drm_pagemap_devmem *devmem_allocation; + void *device_private_page_owner; +}; + +/** + * drm_pagemap_zdd_alloc() - Allocate a zdd structure. + * @device_private_page_owner: Device private pages owner + * + * This function allocates and initializes a new zdd structure. It sets up the + * reference count and initializes the destroy work. + * + * Return: Pointer to the allocated zdd on success, ERR_PTR() on failure. + */ +static struct drm_pagemap_zdd * +drm_pagemap_zdd_alloc(void *device_private_page_owner) +{ + struct drm_pagemap_zdd *zdd; + + zdd = kmalloc(sizeof(*zdd), GFP_KERNEL); + if (!zdd) + return NULL; + + kref_init(&zdd->refcount); + zdd->devmem_allocation = NULL; + zdd->device_private_page_owner = device_private_page_owner; + + return zdd; +} + +/** + * drm_pagemap_zdd_get() - Get a reference to a zdd structure. + * @zdd: Pointer to the zdd structure. + * + * This function increments the reference count of the provided zdd structure. + * + * Return: Pointer to the zdd structure. + */ +static struct drm_pagemap_zdd *drm_pagemap_zdd_get(struct drm_pagemap_zdd *zdd) +{ + kref_get(&zdd->refcount); + return zdd; +} + +/** + * drm_pagemap_zdd_destroy() - Destroy a zdd structure. + * @ref: Pointer to the reference count structure. + * + * This function queues the destroy_work of the zdd for asynchronous destruction. + */ +static void drm_pagemap_zdd_destroy(struct kref *ref) +{ + struct drm_pagemap_zdd *zdd = + container_of(ref, struct drm_pagemap_zdd, refcount); + struct drm_pagemap_devmem *devmem = zdd->devmem_allocation; + + if (devmem) { + complete_all(&devmem->detached); + if (devmem->ops->devmem_release) + devmem->ops->devmem_release(devmem); + } + kfree(zdd); +} + +/** + * drm_pagemap_zdd_put() - Put a zdd reference. + * @zdd: Pointer to the zdd structure. + * + * This function decrements the reference count of the provided zdd structure + * and schedules its destruction if the count drops to zero. + */ +static void drm_pagemap_zdd_put(struct drm_pagemap_zdd *zdd) +{ + kref_put(&zdd->refcount, drm_pagemap_zdd_destroy); +} + +/** + * drm_pagemap_migration_unlock_put_page() - Put a migration page + * @page: Pointer to the page to put + * + * This function unlocks and puts a page. + */ +static void drm_pagemap_migration_unlock_put_page(struct page *page) +{ + unlock_page(page); + put_page(page); +} + +/** + * drm_pagemap_migration_unlock_put_pages() - Put migration pages + * @npages: Number of pages + * @migrate_pfn: Array of migrate page frame numbers + * + * This function unlocks and puts an array of pages. + */ +static void drm_pagemap_migration_unlock_put_pages(unsigned long npages, + unsigned long *migrate_pfn) +{ + unsigned long i; + + for (i = 0; i < npages; ++i) { + struct page *page; + + if (!migrate_pfn[i]) + continue; + + page = migrate_pfn_to_page(migrate_pfn[i]); + drm_pagemap_migration_unlock_put_page(page); + migrate_pfn[i] = 0; + } +} + +/** + * drm_pagemap_get_devmem_page() - Get a reference to a device memory page + * @page: Pointer to the page + * @zdd: Pointer to the GPU SVM zone device data + * + * This function associates the given page with the specified GPU SVM zone + * device data and initializes it for zone device usage. + */ +static void drm_pagemap_get_devmem_page(struct page *page, + struct drm_pagemap_zdd *zdd) +{ + page->zone_device_data = drm_pagemap_zdd_get(zdd); + zone_device_page_init(page); +} + +/** + * drm_pagemap_migrate_map_pages() - Map migration pages for GPU SVM migration + * @dev: The device for which the pages are being mapped + * @dma_addr: Array to store DMA addresses corresponding to mapped pages + * @migrate_pfn: Array of migrate page frame numbers to map + * @npages: Number of pages to map + * @dir: Direction of data transfer (e.g., DMA_BIDIRECTIONAL) + * + * This function maps pages of memory for migration usage in GPU SVM. It + * iterates over each page frame number provided in @migrate_pfn, maps the + * corresponding page, and stores the DMA address in the provided @dma_addr + * array. + * + * Returns: 0 on success, -EFAULT if an error occurs during mapping. + */ +static int drm_pagemap_migrate_map_pages(struct device *dev, + dma_addr_t *dma_addr, + unsigned long *migrate_pfn, + unsigned long npages, + enum dma_data_direction dir) +{ + unsigned long i; + + for (i = 0; i < npages; ++i) { + struct page *page = migrate_pfn_to_page(migrate_pfn[i]); + + if (!page) + continue; + + if (WARN_ON_ONCE(is_zone_device_page(page))) + return -EFAULT; + + dma_addr[i] = dma_map_page(dev, page, 0, PAGE_SIZE, dir); + if (dma_mapping_error(dev, dma_addr[i])) + return -EFAULT; + } + + return 0; +} + +/** + * drm_pagemap_migrate_unmap_pages() - Unmap pages previously mapped for GPU SVM migration + * @dev: The device for which the pages were mapped + * @dma_addr: Array of DMA addresses corresponding to mapped pages + * @npages: Number of pages to unmap + * @dir: Direction of data transfer (e.g., DMA_BIDIRECTIONAL) + * + * This function unmaps previously mapped pages of memory for GPU Shared Virtual + * Memory (SVM). It iterates over each DMA address provided in @dma_addr, checks + * if it's valid and not already unmapped, and unmaps the corresponding page. + */ +static void drm_pagemap_migrate_unmap_pages(struct device *dev, + dma_addr_t *dma_addr, + unsigned long npages, + enum dma_data_direction dir) +{ + unsigned long i; + + for (i = 0; i < npages; ++i) { + if (!dma_addr[i] || dma_mapping_error(dev, dma_addr[i])) + continue; + + dma_unmap_page(dev, dma_addr[i], PAGE_SIZE, dir); + } +} + +static unsigned long +npages_in_range(unsigned long start, unsigned long end) +{ + return (end - start) >> PAGE_SHIFT; +} + +/** + * drm_pagemap_migrate_to_devmem() - Migrate a struct mm_struct range to device memory + * @devmem_allocation: The device memory allocation to migrate to. + * The caller should hold a reference to the device memory allocation, + * and the reference is consumed by this function unless it returns with + * an error. + * @mm: Pointer to the struct mm_struct. + * @start: Start of the virtual address range to migrate. + * @end: End of the virtual address range to migrate. + * @timeslice_ms: The time requested for the migrated pagemap pages to + * be present in @mm before being allowed to be migrated back. + * @pgmap_owner: Not used currently, since only system memory is considered. + * + * This function migrates the specified virtual address range to device memory. + * It performs the necessary setup and invokes the driver-specific operations for + * migration to device memory. Expected to be called while holding the mmap lock in + * at least read mode. + * + * Note: The @timeslice_ms parameter can typically be used to force data to + * remain in pagemap pages long enough for a GPU to perform a task and to prevent + * a migration livelock. One alternative would be for the GPU driver to block + * in a mmu_notifier for the specified amount of time, but adding the + * functionality to the pagemap is likely nicer to the system as a whole. + * + * Return: %0 on success, negative error code on failure. + */ +int drm_pagemap_migrate_to_devmem(struct drm_pagemap_devmem *devmem_allocation, + struct mm_struct *mm, + unsigned long start, unsigned long end, + unsigned long timeslice_ms, + void *pgmap_owner) +{ + const struct drm_pagemap_devmem_ops *ops = devmem_allocation->ops; + struct migrate_vma migrate = { + .start = start, + .end = end, + .pgmap_owner = pgmap_owner, + .flags = MIGRATE_VMA_SELECT_SYSTEM, + }; + unsigned long i, npages = npages_in_range(start, end); + struct vm_area_struct *vas; + struct drm_pagemap_zdd *zdd = NULL; + struct page **pages; + dma_addr_t *dma_addr; + void *buf; + int err; + + mmap_assert_locked(mm); + + if (!ops->populate_devmem_pfn || !ops->copy_to_devmem || + !ops->copy_to_ram) + return -EOPNOTSUPP; + + vas = vma_lookup(mm, start); + if (!vas) { + err = -ENOENT; + goto err_out; + } + + if (end > vas->vm_end || start < vas->vm_start) { + err = -EINVAL; + goto err_out; + } + + if (!vma_is_anonymous(vas)) { + err = -EBUSY; + goto err_out; + } + + buf = kvcalloc(npages, 2 * sizeof(*migrate.src) + sizeof(*dma_addr) + + sizeof(*pages), GFP_KERNEL); + if (!buf) { + err = -ENOMEM; + goto err_out; + } + dma_addr = buf + (2 * sizeof(*migrate.src) * npages); + pages = buf + (2 * sizeof(*migrate.src) + sizeof(*dma_addr)) * npages; + + zdd = drm_pagemap_zdd_alloc(pgmap_owner); + if (!zdd) { + err = -ENOMEM; + goto err_free; + } + + migrate.vma = vas; + migrate.src = buf; + migrate.dst = migrate.src + npages; + + err = migrate_vma_setup(&migrate); + if (err) + goto err_free; + + if (!migrate.cpages) { + err = -EFAULT; + goto err_free; + } + + if (migrate.cpages != npages) { + err = -EBUSY; + goto err_finalize; + } + + err = ops->populate_devmem_pfn(devmem_allocation, npages, migrate.dst); + if (err) + goto err_finalize; + + err = drm_pagemap_migrate_map_pages(devmem_allocation->dev, dma_addr, + migrate.src, npages, DMA_TO_DEVICE); + if (err) + goto err_finalize; + + for (i = 0; i < npages; ++i) { + struct page *page = pfn_to_page(migrate.dst[i]); + + pages[i] = page; + migrate.dst[i] = migrate_pfn(migrate.dst[i]); + drm_pagemap_get_devmem_page(page, zdd); + } + + err = ops->copy_to_devmem(pages, dma_addr, npages); + if (err) + goto err_finalize; + + /* Upon success bind devmem allocation to range and zdd */ + devmem_allocation->timeslice_expiration = get_jiffies_64() + + msecs_to_jiffies(timeslice_ms); + zdd->devmem_allocation = devmem_allocation; /* Owns ref */ + +err_finalize: + if (err) + drm_pagemap_migration_unlock_put_pages(npages, migrate.dst); + migrate_vma_pages(&migrate); + migrate_vma_finalize(&migrate); + drm_pagemap_migrate_unmap_pages(devmem_allocation->dev, dma_addr, npages, + DMA_TO_DEVICE); +err_free: + if (zdd) + drm_pagemap_zdd_put(zdd); + kvfree(buf); +err_out: + return err; +} +EXPORT_SYMBOL_GPL(drm_pagemap_migrate_to_devmem); + +/** + * drm_pagemap_migrate_populate_ram_pfn() - Populate RAM PFNs for a VM area + * @vas: Pointer to the VM area structure, can be NULL + * @fault_page: Fault page + * @npages: Number of pages to populate + * @mpages: Number of pages to migrate + * @src_mpfn: Source array of migrate PFNs + * @mpfn: Array of migrate PFNs to populate + * @addr: Start address for PFN allocation + * + * This function populates the RAM migrate page frame numbers (PFNs) for the + * specified VM area structure. It allocates and locks pages in the VM area for + * RAM usage. If vas is non-NULL use alloc_page_vma for allocation, if NULL use + * alloc_page for allocation. + * + * Return: 0 on success, negative error code on failure. + */ +static int drm_pagemap_migrate_populate_ram_pfn(struct vm_area_struct *vas, + struct page *fault_page, + unsigned long npages, + unsigned long *mpages, + unsigned long *src_mpfn, + unsigned long *mpfn, + unsigned long addr) +{ + unsigned long i; + + for (i = 0; i < npages; ++i, addr += PAGE_SIZE) { + struct page *page, *src_page; + + if (!(src_mpfn[i] & MIGRATE_PFN_MIGRATE)) + continue; + + src_page = migrate_pfn_to_page(src_mpfn[i]); + if (!src_page) + continue; + + if (fault_page) { + if (src_page->zone_device_data != + fault_page->zone_device_data) + continue; + } + + if (vas) + page = alloc_page_vma(GFP_HIGHUSER, vas, addr); + else + page = alloc_page(GFP_HIGHUSER); + + if (!page) + goto free_pages; + + mpfn[i] = migrate_pfn(page_to_pfn(page)); + } + + for (i = 0; i < npages; ++i) { + struct page *page = migrate_pfn_to_page(mpfn[i]); + + if (!page) + continue; + + WARN_ON_ONCE(!trylock_page(page)); + ++*mpages; + } + + return 0; + +free_pages: + for (i = 0; i < npages; ++i) { + struct page *page = migrate_pfn_to_page(mpfn[i]); + + if (!page) + continue; + + put_page(page); + mpfn[i] = 0; + } + return -ENOMEM; +} + +/** + * drm_pagemap_evict_to_ram() - Evict GPU SVM range to RAM + * @devmem_allocation: Pointer to the device memory allocation + * + * Similar to __drm_pagemap_migrate_to_ram but does not require mmap lock and + * migration done via migrate_device_* functions. + * + * Return: 0 on success, negative error code on failure. + */ +int drm_pagemap_evict_to_ram(struct drm_pagemap_devmem *devmem_allocation) +{ + const struct drm_pagemap_devmem_ops *ops = devmem_allocation->ops; + unsigned long npages, mpages = 0; + struct page **pages; + unsigned long *src, *dst; + dma_addr_t *dma_addr; + void *buf; + int i, err = 0; + unsigned int retry_count = 2; + + npages = devmem_allocation->size >> PAGE_SHIFT; + +retry: + if (!mmget_not_zero(devmem_allocation->mm)) + return -EFAULT; + + buf = kvcalloc(npages, 2 * sizeof(*src) + sizeof(*dma_addr) + + sizeof(*pages), GFP_KERNEL); + if (!buf) { + err = -ENOMEM; + goto err_out; + } + src = buf; + dst = buf + (sizeof(*src) * npages); + dma_addr = buf + (2 * sizeof(*src) * npages); + pages = buf + (2 * sizeof(*src) + sizeof(*dma_addr)) * npages; + + err = ops->populate_devmem_pfn(devmem_allocation, npages, src); + if (err) + goto err_free; + + err = migrate_device_pfns(src, npages); + if (err) + goto err_free; + + err = drm_pagemap_migrate_populate_ram_pfn(NULL, NULL, npages, &mpages, + src, dst, 0); + if (err || !mpages) + goto err_finalize; + + err = drm_pagemap_migrate_map_pages(devmem_allocation->dev, dma_addr, + dst, npages, DMA_FROM_DEVICE); + if (err) + goto err_finalize; + + for (i = 0; i < npages; ++i) + pages[i] = migrate_pfn_to_page(src[i]); + + err = ops->copy_to_ram(pages, dma_addr, npages); + if (err) + goto err_finalize; + +err_finalize: + if (err) + drm_pagemap_migration_unlock_put_pages(npages, dst); + migrate_device_pages(src, dst, npages); + migrate_device_finalize(src, dst, npages); + drm_pagemap_migrate_unmap_pages(devmem_allocation->dev, dma_addr, npages, + DMA_FROM_DEVICE); +err_free: + kvfree(buf); +err_out: + mmput_async(devmem_allocation->mm); + + if (completion_done(&devmem_allocation->detached)) + return 0; + + if (retry_count--) { + cond_resched(); + goto retry; + } + + return err ?: -EBUSY; +} +EXPORT_SYMBOL_GPL(drm_pagemap_evict_to_ram); + +/** + * __drm_pagemap_migrate_to_ram() - Migrate GPU SVM range to RAM (internal) + * @vas: Pointer to the VM area structure + * @device_private_page_owner: Device private pages owner + * @page: Pointer to the page for fault handling (can be NULL) + * @fault_addr: Fault address + * @size: Size of migration + * + * This internal function performs the migration of the specified GPU SVM range + * to RAM. It sets up the migration, populates + dma maps RAM PFNs, and + * invokes the driver-specific operations for migration to RAM. + * + * Return: 0 on success, negative error code on failure. + */ +static int __drm_pagemap_migrate_to_ram(struct vm_area_struct *vas, + void *device_private_page_owner, + struct page *page, + unsigned long fault_addr, + unsigned long size) +{ + struct migrate_vma migrate = { + .vma = vas, + .pgmap_owner = device_private_page_owner, + .flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE | + MIGRATE_VMA_SELECT_DEVICE_COHERENT, + .fault_page = page, + }; + struct drm_pagemap_zdd *zdd; + const struct drm_pagemap_devmem_ops *ops; + struct device *dev = NULL; + unsigned long npages, mpages = 0; + struct page **pages; + dma_addr_t *dma_addr; + unsigned long start, end; + void *buf; + int i, err = 0; + + if (page) { + zdd = page->zone_device_data; + if (time_before64(get_jiffies_64(), + zdd->devmem_allocation->timeslice_expiration)) + return 0; + } + + start = ALIGN_DOWN(fault_addr, size); + end = ALIGN(fault_addr + 1, size); + + /* Corner where VMA area struct has been partially unmapped */ + if (start < vas->vm_start) + start = vas->vm_start; + if (end > vas->vm_end) + end = vas->vm_end; + + migrate.start = start; + migrate.end = end; + npages = npages_in_range(start, end); + + buf = kvcalloc(npages, 2 * sizeof(*migrate.src) + sizeof(*dma_addr) + + sizeof(*pages), GFP_KERNEL); + if (!buf) { + err = -ENOMEM; + goto err_out; + } + dma_addr = buf + (2 * sizeof(*migrate.src) * npages); + pages = buf + (2 * sizeof(*migrate.src) + sizeof(*dma_addr)) * npages; + + migrate.vma = vas; + migrate.src = buf; + migrate.dst = migrate.src + npages; + + err = migrate_vma_setup(&migrate); + if (err) + goto err_free; + + /* Raced with another CPU fault, nothing to do */ + if (!migrate.cpages) + goto err_free; + + if (!page) { + for (i = 0; i < npages; ++i) { + if (!(migrate.src[i] & MIGRATE_PFN_MIGRATE)) + continue; + + page = migrate_pfn_to_page(migrate.src[i]); + break; + } + + if (!page) + goto err_finalize; + } + zdd = page->zone_device_data; + ops = zdd->devmem_allocation->ops; + dev = zdd->devmem_allocation->dev; + + err = drm_pagemap_migrate_populate_ram_pfn(vas, page, npages, &mpages, + migrate.src, migrate.dst, + start); + if (err) + goto err_finalize; + + err = drm_pagemap_migrate_map_pages(dev, dma_addr, migrate.dst, npages, + DMA_FROM_DEVICE); + if (err) + goto err_finalize; + + for (i = 0; i < npages; ++i) + pages[i] = migrate_pfn_to_page(migrate.src[i]); + + err = ops->copy_to_ram(pages, dma_addr, npages); + if (err) + goto err_finalize; + +err_finalize: + if (err) + drm_pagemap_migration_unlock_put_pages(npages, migrate.dst); + migrate_vma_pages(&migrate); + migrate_vma_finalize(&migrate); + if (dev) + drm_pagemap_migrate_unmap_pages(dev, dma_addr, npages, + DMA_FROM_DEVICE); +err_free: + kvfree(buf); +err_out: + + return err; +} + +/** + * drm_pagemap_page_free() - Put GPU SVM zone device data associated with a page + * @page: Pointer to the page + * + * This function is a callback used to put the GPU SVM zone device data + * associated with a page when it is being released. + */ +static void drm_pagemap_page_free(struct page *page) +{ + drm_pagemap_zdd_put(page->zone_device_data); +} + +/** + * drm_pagemap_migrate_to_ram() - Migrate a virtual range to RAM (page fault handler) + * @vmf: Pointer to the fault information structure + * + * This function is a page fault handler used to migrate a virtual range + * to ram. The device memory allocation in which the device page is found is + * migrated in its entirety. + * + * Returns: + * VM_FAULT_SIGBUS on failure, 0 on success. + */ +static vm_fault_t drm_pagemap_migrate_to_ram(struct vm_fault *vmf) +{ + struct drm_pagemap_zdd *zdd = vmf->page->zone_device_data; + int err; + + err = __drm_pagemap_migrate_to_ram(vmf->vma, + zdd->device_private_page_owner, + vmf->page, vmf->address, + zdd->devmem_allocation->size); + + return err ? VM_FAULT_SIGBUS : 0; +} + +static const struct dev_pagemap_ops drm_pagemap_pagemap_ops = { + .page_free = drm_pagemap_page_free, + .migrate_to_ram = drm_pagemap_migrate_to_ram, +}; + +/** + * drm_pagemap_pagemap_ops_get() - Retrieve GPU SVM device page map operations + * + * Returns: + * Pointer to the GPU SVM device page map operations structure. + */ +const struct dev_pagemap_ops *drm_pagemap_pagemap_ops_get(void) +{ + return &drm_pagemap_pagemap_ops; +} +EXPORT_SYMBOL_GPL(drm_pagemap_pagemap_ops_get); + +/** + * drm_pagemap_devmem_init() - Initialize a drm_pagemap device memory allocation + * + * @devmem_allocation: The struct drm_pagemap_devmem to initialize. + * @dev: Pointer to the device structure which device memory allocation belongs to + * @mm: Pointer to the mm_struct for the address space + * @ops: Pointer to the operations structure for GPU SVM device memory + * @dpagemap: The struct drm_pagemap we're allocating from. + * @size: Size of device memory allocation + */ +void drm_pagemap_devmem_init(struct drm_pagemap_devmem *devmem_allocation, + struct device *dev, struct mm_struct *mm, + const struct drm_pagemap_devmem_ops *ops, + struct drm_pagemap *dpagemap, size_t size) +{ + init_completion(&devmem_allocation->detached); + devmem_allocation->dev = dev; + devmem_allocation->mm = mm; + devmem_allocation->ops = ops; + devmem_allocation->dpagemap = dpagemap; + devmem_allocation->size = size; +} +EXPORT_SYMBOL_GPL(drm_pagemap_devmem_init); + +/** + * drm_pagemap_page_to_dpagemap() - Return a pointer the drm_pagemap of a page + * @page: The struct page. + * + * Return: A pointer to the struct drm_pagemap of a device private page that + * was populated from the struct drm_pagemap. If the page was *not* populated + * from a struct drm_pagemap, the result is undefined and the function call + * may result in dereferencing and invalid address. + */ +struct drm_pagemap *drm_pagemap_page_to_dpagemap(struct page *page) +{ + struct drm_pagemap_zdd *zdd = page->zone_device_data; + + return zdd->devmem_allocation->dpagemap; +} +EXPORT_SYMBOL_GPL(drm_pagemap_page_to_dpagemap); + +/** + * drm_pagemap_populate_mm() - Populate a virtual range with device memory pages + * @dpagemap: Pointer to the drm_pagemap managing the device memory + * @start: Start of the virtual range to populate. + * @end: End of the virtual range to populate. + * @mm: Pointer to the virtual address space. + * @timeslice_ms: The time requested for the migrated pagemap pages to + * be present in @mm before being allowed to be migrated back. + * + * Attempt to populate a virtual range with device memory pages, + * clearing them or migrating data from the existing pages if necessary. + * The function is best effort only, and implementations may vary + * in how hard they try to satisfy the request. + * + * Return: %0 on success, negative error code on error. If the hardware + * device was removed / unbound the function will return %-ENODEV. + */ +int drm_pagemap_populate_mm(struct drm_pagemap *dpagemap, + unsigned long start, unsigned long end, + struct mm_struct *mm, + unsigned long timeslice_ms) +{ + int err; + + if (!mmget_not_zero(mm)) + return -EFAULT; + mmap_read_lock(mm); + err = dpagemap->ops->populate_mm(dpagemap, start, end, mm, + timeslice_ms); + mmap_read_unlock(mm); + mmput(mm); + + return err; +} +EXPORT_SYMBOL(drm_pagemap_populate_mm); |