// SPDX-License-Identifier: GPL-2.0 OR MIT
/*
 * Copyright 2020-2021 Advanced Micro Devices, Inc.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
 * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
 * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
 * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
 * OTHER DEALINGS IN THE SOFTWARE.
 */

#include <linux/types.h>
#include <linux/sched/task.h>
#include "amdgpu_sync.h"
#include "amdgpu_object.h"
#include "amdgpu_vm.h"
#include "amdgpu_mn.h"
#include "amdgpu.h"
#include "amdgpu_xgmi.h"
#include "kfd_priv.h"
#include "kfd_svm.h"
#include "kfd_migrate.h"

#define AMDGPU_SVM_RANGE_RESTORE_DELAY_MS 1

/* Long enough to ensure no retry fault comes after svm range is restored and
 * page table is updated.
 */
#define AMDGPU_SVM_RANGE_RETRY_FAULT_PENDING    2000

static void svm_range_evict_svm_bo_worker(struct work_struct *work);
static bool
svm_range_cpu_invalidate_pagetables(struct mmu_interval_notifier *mni,
                                    const struct mmu_notifier_range *range,
                                    unsigned long cur_seq);

static const struct mmu_interval_notifier_ops svm_range_mn_ops = {
        .invalidate = svm_range_cpu_invalidate_pagetables,
};

/**
 * svm_range_unlink - unlink svm_range from lists and interval tree
 * @prange: svm range structure to be removed
 *
 * Remove the svm_range from the svms and svm_bo lists and the svms
 * interval tree.
 *
 * Context: The caller must hold svms->lock
 */
static void svm_range_unlink(struct svm_range *prange)
{
        pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx]\n", prange->svms,
                 prange, prange->start, prange->last);

        if (prange->svm_bo) {
                spin_lock(&prange->svm_bo->list_lock);
                list_del(&prange->svm_bo_list);
                spin_unlock(&prange->svm_bo->list_lock);
        }

        list_del(&prange->list);
        if (prange->it_node.start != 0 && prange->it_node.last != 0)
                interval_tree_remove(&prange->it_node, &prange->svms->objects);
}

static void
svm_range_add_notifier_locked(struct mm_struct *mm, struct svm_range *prange)
{
        pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx]\n", prange->svms,
                 prange, prange->start, prange->last);

        mmu_interval_notifier_insert_locked(&prange->notifier, mm,
                                     prange->start << PAGE_SHIFT,
                                     prange->npages << PAGE_SHIFT,
                                     &svm_range_mn_ops);
}

/**
 * svm_range_add_to_svms - add svm range to svms
 * @prange: svm range structure to be added
 *
 * Add the svm range to svms interval tree and link list
 *
 * Context: The caller must hold svms->lock
 */
static void svm_range_add_to_svms(struct svm_range *prange)
{
        pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx]\n", prange->svms,
                 prange, prange->start, prange->last);

        list_add_tail(&prange->list, &prange->svms->list);
        prange->it_node.start = prange->start;
        prange->it_node.last = prange->last;
        interval_tree_insert(&prange->it_node, &prange->svms->objects);
}

static void svm_range_remove_notifier(struct svm_range *prange)
{
        pr_debug("remove notifier svms 0x%p prange 0x%p [0x%lx 0x%lx]\n",
                 prange->svms, prange,
                 prange->notifier.interval_tree.start >> PAGE_SHIFT,
                 prange->notifier.interval_tree.last >> PAGE_SHIFT);

        if (prange->notifier.interval_tree.start != 0 &&
            prange->notifier.interval_tree.last != 0)
                mmu_interval_notifier_remove(&prange->notifier);
}

static bool
svm_is_valid_dma_mapping_addr(struct device *dev, dma_addr_t dma_addr)
{
        return dma_addr && !dma_mapping_error(dev, dma_addr) &&
               !(dma_addr & SVM_RANGE_VRAM_DOMAIN);
}

static int
svm_range_dma_map_dev(struct amdgpu_device *adev, struct svm_range *prange,
                      unsigned long offset, unsigned long npages,
                      unsigned long *hmm_pfns, uint32_t gpuidx)
{
        enum dma_data_direction dir = DMA_BIDIRECTIONAL;
        dma_addr_t *addr = prange->dma_addr[gpuidx];
        struct device *dev = adev->dev;
        struct page *page;
        int i, r;

        if (!addr) {
                addr = kvmalloc_array(prange->npages, sizeof(*addr),
                                      GFP_KERNEL | __GFP_ZERO);
                if (!addr)
                        return -ENOMEM;
                prange->dma_addr[gpuidx] = addr;
        }

        addr += offset;
        for (i = 0; i < npages; i++) {
                if (svm_is_valid_dma_mapping_addr(dev, addr[i]))
                        dma_unmap_page(dev, addr[i], PAGE_SIZE, dir);

                page = hmm_pfn_to_page(hmm_pfns[i]);
                if (is_zone_device_page(page)) {
                        struct amdgpu_device *bo_adev =
                                        amdgpu_ttm_adev(prange->svm_bo->bo->tbo.bdev);

                        addr[i] = (hmm_pfns[i] << PAGE_SHIFT) +
                                   bo_adev->vm_manager.vram_base_offset -
                                   bo_adev->kfd.dev->pgmap.range.start;
                        addr[i] |= SVM_RANGE_VRAM_DOMAIN;
                        pr_debug("vram address detected: 0x%llx\n", addr[i]);
                        continue;
                }
                addr[i] = dma_map_page(dev, page, 0, PAGE_SIZE, dir);
                r = dma_mapping_error(dev, addr[i]);
                if (r) {
                        pr_debug("failed %d dma_map_page\n", r);
                        return r;
                }
                pr_debug("dma mapping 0x%llx for page addr 0x%lx\n",
                         addr[i] >> PAGE_SHIFT, page_to_pfn(page));
        }
        return 0;
}

static int
svm_range_dma_map(struct svm_range *prange, unsigned long *bitmap,
                  unsigned long offset, unsigned long npages,
                  unsigned long *hmm_pfns)
{
        struct kfd_process *p;
        uint32_t gpuidx;
        int r;

        p = container_of(prange->svms, struct kfd_process, svms);

        for_each_set_bit(gpuidx, bitmap, MAX_GPU_INSTANCE) {
                struct kfd_process_device *pdd;
                struct amdgpu_device *adev;

                pr_debug("mapping to gpu idx 0x%x\n", gpuidx);
                pdd = kfd_process_device_from_gpuidx(p, gpuidx);
                if (!pdd) {
                        pr_debug("failed to find device idx %d\n", gpuidx);
                        return -EINVAL;
                }
                adev = (struct amdgpu_device *)pdd->dev->kgd;

                r = svm_range_dma_map_dev(adev, prange, offset, npages,
                                          hmm_pfns, gpuidx);
                if (r)
                        break;
        }

        return r;
}

void svm_range_dma_unmap(struct device *dev, dma_addr_t *dma_addr,
                         unsigned long offset, unsigned long npages)
{
        enum dma_data_direction dir = DMA_BIDIRECTIONAL;
        int i;

        if (!dma_addr)
                return;

        for (i = offset; i < offset + npages; i++) {
                if (!svm_is_valid_dma_mapping_addr(dev, dma_addr[i]))
                        continue;
                pr_debug("dma unmapping 0x%llx\n", dma_addr[i] >> PAGE_SHIFT);
                dma_unmap_page(dev, dma_addr[i], PAGE_SIZE, dir);
                dma_addr[i] = 0;
        }
}

void svm_range_free_dma_mappings(struct svm_range *prange)
{
        struct kfd_process_device *pdd;
        dma_addr_t *dma_addr;
        struct device *dev;
        struct kfd_process *p;
        uint32_t gpuidx;

        p = container_of(prange->svms, struct kfd_process, svms);

        for (gpuidx = 0; gpuidx < MAX_GPU_INSTANCE; gpuidx++) {
                dma_addr = prange->dma_addr[gpuidx];
                if (!dma_addr)
                        continue;

                pdd = kfd_process_device_from_gpuidx(p, gpuidx);
                if (!pdd) {
                        pr_debug("failed to find device idx %d\n", gpuidx);
                        continue;
                }
                dev = &pdd->dev->pdev->dev;
                svm_range_dma_unmap(dev, dma_addr, 0, prange->npages);
                kvfree(dma_addr);
                prange->dma_addr[gpuidx] = NULL;
        }
}

static void svm_range_free(struct svm_range *prange)
{
        pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx]\n", prange->svms, prange,
                 prange->start, prange->last);

        svm_range_vram_node_free(prange);
        svm_range_free_dma_mappings(prange);
        mutex_destroy(&prange->lock);
        mutex_destroy(&prange->migrate_mutex);
        kfree(prange);
}

static void
svm_range_set_default_attributes(int32_t *location, int32_t *prefetch_loc,
                                 uint8_t *granularity, uint32_t *flags)
{
        *location = KFD_IOCTL_SVM_LOCATION_UNDEFINED;
        *prefetch_loc = KFD_IOCTL_SVM_LOCATION_UNDEFINED;
        *granularity = 9;
        *flags =
                KFD_IOCTL_SVM_FLAG_HOST_ACCESS | KFD_IOCTL_SVM_FLAG_COHERENT;
}

static struct
svm_range *svm_range_new(struct svm_range_list *svms, uint64_t start,
                         uint64_t last)
{
        uint64_t size = last - start + 1;
        struct svm_range *prange;
        struct kfd_process *p;

        prange = kzalloc(sizeof(*prange), GFP_KERNEL);
        if (!prange)
                return NULL;
        prange->npages = size;
        prange->svms = svms;
        prange->start = start;
        prange->last = last;
        INIT_LIST_HEAD(&prange->list);
        INIT_LIST_HEAD(&prange->update_list);
        INIT_LIST_HEAD(&prange->remove_list);
        INIT_LIST_HEAD(&prange->insert_list);
        INIT_LIST_HEAD(&prange->svm_bo_list);
        INIT_LIST_HEAD(&prange->deferred_list);
        INIT_LIST_HEAD(&prange->child_list);
        atomic_set(&prange->invalid, 0);
        prange->validate_timestamp = 0;
        mutex_init(&prange->migrate_mutex);
        mutex_init(&prange->lock);

        p = container_of(svms, struct kfd_process, svms);
        if (p->xnack_enabled)
                bitmap_copy(prange->bitmap_access, svms->bitmap_supported,
                            MAX_GPU_INSTANCE);

        svm_range_set_default_attributes(&prange->preferred_loc,
                                         &prange->prefetch_loc,
                                         &prange->granularity, &prange->flags);

        pr_debug("svms 0x%p [0x%llx 0x%llx]\n", svms, start, last);

        return prange;
}

static bool svm_bo_ref_unless_zero(struct svm_range_bo *svm_bo)
{
        if (!svm_bo || !kref_get_unless_zero(&svm_bo->kref))
                return false;

        return true;
}

static void svm_range_bo_release(struct kref *kref)
{
        struct svm_range_bo *svm_bo;

        svm_bo = container_of(kref, struct svm_range_bo, kref);
        spin_lock(&svm_bo->list_lock);
        while (!list_empty(&svm_bo->range_list)) {
                struct svm_range *prange =
                                list_first_entry(&svm_bo->range_list,
                                                struct svm_range, svm_bo_list);
                /* list_del_init tells a concurrent svm_range_vram_node_new when
                 * it's safe to reuse the svm_bo pointer and svm_bo_list head.
                 */
                list_del_init(&prange->svm_bo_list);
                spin_unlock(&svm_bo->list_lock);

                pr_debug("svms 0x%p [0x%lx 0x%lx]\n", prange->svms,
                         prange->start, prange->last);
                mutex_lock(&prange->lock);
                prange->svm_bo = NULL;
                mutex_unlock(&prange->lock);

                spin_lock(&svm_bo->list_lock);
        }
        spin_unlock(&svm_bo->list_lock);
        if (!dma_fence_is_signaled(&svm_bo->eviction_fence->base)) {
                /* We're not in the eviction worker.
                 * Signal the fence and synchronize with any
                 * pending eviction work.
                 */
                dma_fence_signal(&svm_bo->eviction_fence->base);
                cancel_work_sync(&svm_bo->eviction_work);
        }
        dma_fence_put(&svm_bo->eviction_fence->base);
        amdgpu_bo_unref(&svm_bo->bo);
        kfree(svm_bo);
}

void svm_range_bo_unref(struct svm_range_bo *svm_bo)
{
        if (!svm_bo)
                return;

        kref_put(&svm_bo->kref, svm_range_bo_release);
}

static bool
svm_range_validate_svm_bo(struct amdgpu_device *adev, struct svm_range *prange)
{
        struct amdgpu_device *bo_adev;

        mutex_lock(&prange->lock);
        if (!prange->svm_bo) {
                mutex_unlock(&prange->lock);
                return false;
        }
        if (prange->ttm_res) {
                /* We still have a reference, all is well */
                mutex_unlock(&prange->lock);
                return true;
        }
        if (svm_bo_ref_unless_zero(prange->svm_bo)) {
                /*
                 * Migrate from GPU to GPU, remove range from source bo_adev
                 * svm_bo range list, and return false to allocate svm_bo from
                 * destination adev.
                 */
                bo_adev = amdgpu_ttm_adev(prange->svm_bo->bo->tbo.bdev);
                if (bo_adev != adev) {
                        mutex_unlock(&prange->lock);

                        spin_lock(&prange->svm_bo->list_lock);
                        list_del_init(&prange->svm_bo_list);
                        spin_unlock(&prange->svm_bo->list_lock);

                        svm_range_bo_unref(prange->svm_bo);
                        return false;
                }
                if (READ_ONCE(prange->svm_bo->evicting)) {
                        struct dma_fence *f;
                        struct svm_range_bo *svm_bo;
                        /* The BO is getting evicted,
                         * we need to get a new one
                         */
                        mutex_unlock(&prange->lock);
                        svm_bo = prange->svm_bo;
                        f = dma_fence_get(&svm_bo->eviction_fence->base);
                        svm_range_bo_unref(prange->svm_bo);
                        /* wait for the fence to avoid long spin-loop
                         * at list_empty_careful
                         */
                        dma_fence_wait(f, false);
                        dma_fence_put(f);
                } else {
                        /* The BO was still around and we got
                         * a new reference to it
                         */
                        mutex_unlock(&prange->lock);
                        pr_debug("reuse old bo svms 0x%p [0x%lx 0x%lx]\n",
                                 prange->svms, prange->start, prange->last);

                        prange->ttm_res = prange->svm_bo->bo->tbo.resource;
                        return true;
                }

        } else {
                mutex_unlock(&prange->lock);
        }

        /* We need a new svm_bo. Spin-loop to wait for concurrent
         * svm_range_bo_release to finish removing this range from
         * its range list. After this, it is safe to reuse the
         * svm_bo pointer and svm_bo_list head.
         */
        while (!list_empty_careful(&prange->svm_bo_list))
                ;

        return false;
}

static struct svm_range_bo *svm_range_bo_new(void)
{
        struct svm_range_bo *svm_bo;

        svm_bo = kzalloc(sizeof(*svm_bo), GFP_KERNEL);
        if (!svm_bo)
                return NULL;

        kref_init(&svm_bo->kref);
        INIT_LIST_HEAD(&svm_bo->range_list);
        spin_lock_init(&svm_bo->list_lock);

        return svm_bo;
}

int
svm_range_vram_node_new(struct amdgpu_device *adev, struct svm_range *prange,
                        bool clear)
{
        struct amdgpu_bo_param bp;
        struct svm_range_bo *svm_bo;
        struct amdgpu_bo_user *ubo;
        struct amdgpu_bo *bo;
        struct kfd_process *p;
        struct mm_struct *mm;
        int r;

        p = container_of(prange->svms, struct kfd_process, svms);
        pr_debug("pasid: %x svms 0x%p [0x%lx 0x%lx]\n", p->pasid, prange->svms,
                 prange->start, prange->last);

        if (svm_range_validate_svm_bo(adev, prange))
                return 0;

        svm_bo = svm_range_bo_new();
        if (!svm_bo) {
                pr_debug("failed to alloc svm bo\n");
                return -ENOMEM;
        }
        mm = get_task_mm(p->lead_thread);
        if (!mm) {
                pr_debug("failed to get mm\n");
                kfree(svm_bo);
                return -ESRCH;
        }
        svm_bo->svms = prange->svms;
        svm_bo->eviction_fence =
                amdgpu_amdkfd_fence_create(dma_fence_context_alloc(1),
                                           mm,
                                           svm_bo);
        mmput(mm);
        INIT_WORK(&svm_bo->eviction_work, svm_range_evict_svm_bo_worker);
        svm_bo->evicting = 0;
        memset(&bp, 0, sizeof(bp));
        bp.size = prange->npages * PAGE_SIZE;
        bp.byte_align = PAGE_SIZE;
        bp.domain = AMDGPU_GEM_DOMAIN_VRAM;
        bp.flags = AMDGPU_GEM_CREATE_NO_CPU_ACCESS;
        bp.flags |= clear ? AMDGPU_GEM_CREATE_VRAM_CLEARED : 0;
        bp.flags |= AMDGPU_AMDKFD_CREATE_SVM_BO;
        bp.type = ttm_bo_type_device;
        bp.resv = NULL;

        r = amdgpu_bo_create_user(adev, &bp, &ubo);
        if (r) {
                pr_debug("failed %d to create bo\n", r);
                goto create_bo_failed;
        }
        bo = &ubo->bo;
        r = amdgpu_bo_reserve(bo, true);
        if (r) {
                pr_debug("failed %d to reserve bo\n", r);
                goto reserve_bo_failed;
        }

        r = dma_resv_reserve_shared(bo->tbo.base.resv, 1);
        if (r) {
                pr_debug("failed %d to reserve bo\n", r);
                amdgpu_bo_unreserve(bo);
                goto reserve_bo_failed;
        }
        amdgpu_bo_fence(bo, &svm_bo->eviction_fence->base, true);

        amdgpu_bo_unreserve(bo);

        svm_bo->bo = bo;
        prange->svm_bo = svm_bo;
        prange->ttm_res = bo->tbo.resource;
        prange->offset = 0;

        spin_lock(&svm_bo->list_lock);
        list_add(&prange->svm_bo_list, &svm_bo->range_list);
        spin_unlock(&svm_bo->list_lock);

        return 0;

reserve_bo_failed:
        amdgpu_bo_unref(&bo);
create_bo_failed:
        dma_fence_put(&svm_bo->eviction_fence->base);
        kfree(svm_bo);
        prange->ttm_res = NULL;

        return r;
}

void svm_range_vram_node_free(struct svm_range *prange)
{
        svm_range_bo_unref(prange->svm_bo);
        prange->ttm_res = NULL;
}

struct amdgpu_device *
svm_range_get_adev_by_id(struct svm_range *prange, uint32_t gpu_id)
{
        struct kfd_process_device *pdd;
        struct kfd_process *p;
        int32_t gpu_idx;

        p = container_of(prange->svms, struct kfd_process, svms);

        gpu_idx = kfd_process_gpuidx_from_gpuid(p, gpu_id);
        if (gpu_idx < 0) {
                pr_debug("failed to get device by id 0x%x\n", gpu_id);
                return NULL;
        }
        pdd = kfd_process_device_from_gpuidx(p, gpu_idx);
        if (!pdd) {
                pr_debug("failed to get device by idx 0x%x\n", gpu_idx);
                return NULL;
        }

        return (struct amdgpu_device *)pdd->dev->kgd;
}

struct kfd_process_device *
svm_range_get_pdd_by_adev(struct svm_range *prange, struct amdgpu_device *adev)
{
        struct kfd_process *p;
        int32_t gpu_idx, gpuid;
        int r;

        p = container_of(prange->svms, struct kfd_process, svms);

        r = kfd_process_gpuid_from_kgd(p, adev, &gpuid, &gpu_idx);
        if (r) {
                pr_debug("failed to get device id by adev %p\n", adev);
                return NULL;
        }

        return kfd_process_device_from_gpuidx(p, gpu_idx);
}

static int svm_range_bo_validate(void *param, struct amdgpu_bo *bo)
{
        struct ttm_operation_ctx ctx = { false, false };

        amdgpu_bo_placement_from_domain(bo, AMDGPU_GEM_DOMAIN_VRAM);

        return ttm_bo_validate(&bo->tbo, &bo->placement, &ctx);
}

static int
svm_range_check_attr(struct kfd_process *p,
                     uint32_t nattr, struct kfd_ioctl_svm_attribute *attrs)
{
        uint32_t i;

        for (i = 0; i < nattr; i++) {
                uint32_t val = attrs[i].value;
                int gpuidx = MAX_GPU_INSTANCE;

                switch (attrs[i].type) {
                case KFD_IOCTL_SVM_ATTR_PREFERRED_LOC:
                        if (val != KFD_IOCTL_SVM_LOCATION_SYSMEM &&
                            val != KFD_IOCTL_SVM_LOCATION_UNDEFINED)
                                gpuidx = kfd_process_gpuidx_from_gpuid(p, val);
                        break;
                case KFD_IOCTL_SVM_ATTR_PREFETCH_LOC:
                        if (val != KFD_IOCTL_SVM_LOCATION_SYSMEM)
                                gpuidx = kfd_process_gpuidx_from_gpuid(p, val);
                        break;
                case KFD_IOCTL_SVM_ATTR_ACCESS:
                case KFD_IOCTL_SVM_ATTR_ACCESS_IN_PLACE:
                case KFD_IOCTL_SVM_ATTR_NO_ACCESS:
                        gpuidx = kfd_process_gpuidx_from_gpuid(p, val);
                        break;
                case KFD_IOCTL_SVM_ATTR_SET_FLAGS:
                        break;
                case KFD_IOCTL_SVM_ATTR_CLR_FLAGS:
                        break;
                case KFD_IOCTL_SVM_ATTR_GRANULARITY:
                        break;
                default:
                        pr_debug("unknown attr type 0x%x\n", attrs[i].type);
                        return -EINVAL;
                }

                if (gpuidx < 0) {
                        pr_debug("no GPU 0x%x found\n", val);
                        return -EINVAL;
                } else if (gpuidx < MAX_GPU_INSTANCE &&
                           !test_bit(gpuidx, p->svms.bitmap_supported)) {
                        pr_debug("GPU 0x%x not supported\n", val);
                        return -EINVAL;
                }
        }

        return 0;
}

static void
svm_range_apply_attrs(struct kfd_process *p, struct svm_range *prange,
                      uint32_t nattr, struct kfd_ioctl_svm_attribute *attrs)
{
        uint32_t i;
        int gpuidx;

        for (i = 0; i < nattr; i++) {
                switch (attrs[i].type) {
                case KFD_IOCTL_SVM_ATTR_PREFERRED_LOC:
                        prange->preferred_loc = attrs[i].value;
                        break;
                case KFD_IOCTL_SVM_ATTR_PREFETCH_LOC:
                        prange->prefetch_loc = attrs[i].value;
                        break;
                case KFD_IOCTL_SVM_ATTR_ACCESS:
                case KFD_IOCTL_SVM_ATTR_ACCESS_IN_PLACE:
                case KFD_IOCTL_SVM_ATTR_NO_ACCESS:
                        gpuidx = kfd_process_gpuidx_from_gpuid(p,
                                                               attrs[i].value);
                        if (attrs[i].type == KFD_IOCTL_SVM_ATTR_NO_ACCESS) {
                                bitmap_clear(prange->bitmap_access, gpuidx, 1);
                                bitmap_clear(prange->bitmap_aip, gpuidx, 1);
                        } else if (attrs[i].type == KFD_IOCTL_SVM_ATTR_ACCESS) {
                                bitmap_set(prange->bitmap_access, gpuidx, 1);
                                bitmap_clear(prange->bitmap_aip, gpuidx, 1);
                        } else {
                                bitmap_clear(prange->bitmap_access, gpuidx, 1);
                                bitmap_set(prange->bitmap_aip, gpuidx, 1);
                        }
                        break;
                case KFD_IOCTL_SVM_ATTR_SET_FLAGS:
                        prange->flags |= attrs[i].value;
                        break;
                case KFD_IOCTL_SVM_ATTR_CLR_FLAGS:
                        prange->flags &= ~attrs[i].value;
                        break;
                case KFD_IOCTL_SVM_ATTR_GRANULARITY:
                        prange->granularity = attrs[i].value;
                        break;
                default:
                        WARN_ONCE(1, "svm_range_check_attrs wasn't called?");
                }
        }
}

/**
 * svm_range_debug_dump - print all range information from svms
 * @svms: svm range list header
 *
 * debug output svm range start, end, prefetch location from svms
 * interval tree and link list
 *
 * Context: The caller must hold svms->lock
 */
static void svm_range_debug_dump(struct svm_range_list *svms)
{
        struct interval_tree_node *node;
        struct svm_range *prange;

        pr_debug("dump svms 0x%p list\n", svms);
        pr_debug("range\tstart\tpage\tend\t\tlocation\n");

        list_for_each_entry(prange, &svms->list, list) {
                pr_debug("0x%p 0x%lx\t0x%llx\t0x%llx\t0x%x\n",
                         prange, prange->start, prange->npages,
                         prange->start + prange->npages - 1,
                         prange->actual_loc);
        }

        pr_debug("dump svms 0x%p interval tree\n", svms);
        pr_debug("range\tstart\tpage\tend\t\tlocation\n");
        node = interval_tree_iter_first(&svms->objects, 0, ~0ULL);
        while (node) {
                prange = container_of(node, struct svm_range, it_node);
                pr_debug("0x%p 0x%lx\t0x%llx\t0x%llx\t0x%x\n",
                         prange, prange->start, prange->npages,
                         prange->start + prange->npages - 1,
                         prange->actual_loc);
                node = interval_tree_iter_next(node, 0, ~0ULL);
        }
}

static bool
svm_range_is_same_attrs(struct svm_range *old, struct svm_range *new)
{
        return (old->prefetch_loc == new->prefetch_loc &&
                old->flags == new->flags &&
                old->granularity == new->granularity);
}

static int
svm_range_split_array(void *ppnew, void *ppold, size_t size,
                      uint64_t old_start, uint64_t old_n,
                      uint64_t new_start, uint64_t new_n)
{
        unsigned char *new, *old, *pold;
        uint64_t d;

        if (!ppold)
                return 0;
        pold = *(unsigned char **)ppold;
        if (!pold)
                return 0;

        new = kvmalloc_array(new_n, size, GFP_KERNEL);
        if (!new)
                return -ENOMEM;

        d = (new_start - old_start) * size;
        memcpy(new, pold + d, new_n * size);

        old = kvmalloc_array(old_n, size, GFP_KERNEL);
        if (!old) {
                kvfree(new);
                return -ENOMEM;
        }

        d = (new_start == old_start) ? new_n * size : 0;
        memcpy(old, pold + d, old_n * size);

        kvfree(pold);
        *(void **)ppold = old;
        *(void **)ppnew = new;

        return 0;
}

static int
svm_range_split_pages(struct svm_range *new, struct svm_range *old,
                      uint64_t start, uint64_t last)
{
        uint64_t npages = last - start + 1;
        int i, r;

        for (i = 0; i < MAX_GPU_INSTANCE; i++) {
                r = svm_range_split_array(&new->dma_addr[i], &old->dma_addr[i],
                                          sizeof(*old->dma_addr[i]), old->start,
                                          npages, new->start, new->npages);
                if (r)
                        return r;
        }

        return 0;
}

static int
svm_range_split_nodes(struct svm_range *new, struct svm_range *old,
                      uint64_t start, uint64_t last)
{
        uint64_t npages = last - start + 1;

        pr_debug("svms 0x%p new prange 0x%p start 0x%lx [0x%llx 0x%llx]\n",
                 new->svms, new, new->start, start, last);

        if (new->start == old->start) {
                new->offset = old->offset;
                old->offset += new->npages;
        } else {
                new->offset = old->offset + npages;
        }

        new->svm_bo = svm_range_bo_ref(old->svm_bo);
        new->ttm_res = old->ttm_res;

        spin_lock(&new->svm_bo->list_lock);
        list_add(&new->svm_bo_list, &new->svm_bo->range_list);
        spin_unlock(&new->svm_bo->list_lock);

        return 0;
}

/**
 * svm_range_split_adjust - split range and adjust
 *
 * @new: new range
 * @old: the old range
 * @start: the old range adjust to start address in pages
 * @last: the old range adjust to last address in pages
 *
 * Copy system memory dma_addr or vram ttm_res in old range to new
 * range from new_start up to size new->npages, the remaining old range is from
 * start to last
 *
 * Return:
 * 0 - OK, -ENOMEM - out of memory
 */
static int
svm_range_split_adjust(struct svm_range *new, struct svm_range *old,
                      uint64_t start, uint64_t last)
{
        int r;

        pr_debug("svms 0x%p new 0x%lx old [0x%lx 0x%lx] => [0x%llx 0x%llx]\n",
                 new->svms, new->start, old->start, old->last, start, last);

        if (new->start < old->start ||
            new->last > old->last) {
                WARN_ONCE(1, "invalid new range start or last\n");
                return -EINVAL;
        }

        r = svm_range_split_pages(new, old, start, last);
        if (r)
                return r;

        if (old->actual_loc && old->ttm_res) {
                r = svm_range_split_nodes(new, old, start, last);
                if (r)
                        return r;
        }

        old->npages = last - start + 1;
        old->start = start;
        old->last = last;
        new->flags = old->flags;
        new->preferred_loc = old->preferred_loc;
        new->prefetch_loc = old->prefetch_loc;
        new->actual_loc = old->actual_loc;
        new->granularity = old->granularity;
        bitmap_copy(new->bitmap_access, old->bitmap_access, MAX_GPU_INSTANCE);
        bitmap_copy(new->bitmap_aip, old->bitmap_aip, MAX_GPU_INSTANCE);

        return 0;
}

/**
 * svm_range_split - split a range in 2 ranges
 *
 * @prange: the svm range to split
 * @start: the remaining range start address in pages
 * @last: the remaining range last address in pages
 * @new: the result new range generated
 *
 * Two cases only:
 * case 1: if start == prange->start
 *         prange ==> prange[start, last]
 *         new range [last + 1, prange->last]
 *
 * case 2: if last == prange->last
 *         prange ==> prange[start, last]
 *         new range [prange->start, start - 1]
 *
 * Return:
 * 0 - OK, -ENOMEM - out of memory, -EINVAL - invalid start, last
 */
static int
svm_range_split(struct svm_range *prange, uint64_t start, uint64_t last,
                struct svm_range **new)
{
        uint64_t old_start = prange->start;
        uint64_t old_last = prange->last;
        struct svm_range_list *svms;
        int r = 0;

        pr_debug("svms 0x%p [0x%llx 0x%llx] to [0x%llx 0x%llx]\n", prange->svms,
                 old_start, old_last, start, last);

        if (old_start != start && old_last != last)
                return -EINVAL;
        if (start < old_start || last > old_last)
                return -EINVAL;

        svms = prange->svms;
        if (old_start == start)
                *new = svm_range_new(svms, last + 1, old_last);
        else
                *new = svm_range_new(svms, old_start, start - 1);
        if (!*new)
                return -ENOMEM;

        r = svm_range_split_adjust(*new, prange, start, last);
        if (r) {
                pr_debug("failed %d split [0x%llx 0x%llx] to [0x%llx 0x%llx]\n",
                         r, old_start, old_last, start, last);
                svm_range_free(*new);
                *new = NULL;
        }

        return r;
}

static int
svm_range_split_tail(struct svm_range *prange, struct svm_range *new,
                     uint64_t new_last, struct list_head *insert_list)
{
        struct svm_range *tail;
        int r = svm_range_split(prange, prange->start, new_last, &tail);

        if (!r)
                list_add(&tail->insert_list, insert_list);
        return r;
}

static int
svm_range_split_head(struct svm_range *prange, struct svm_range *new,
                     uint64_t new_start, struct list_head *insert_list)
{
        struct svm_range *head;
        int r = svm_range_split(prange, new_start, prange->last, &head);

        if (!r)
                list_add(&head->insert_list, insert_list);
        return r;
}

static void
svm_range_add_child(struct svm_range *prange, struct mm_struct *mm,
                    struct svm_range *pchild, enum svm_work_list_ops op)
{
        pr_debug("add child 0x%p [0x%lx 0x%lx] to prange 0x%p child list %d\n",
                 pchild, pchild->start, pchild->last, prange, op);

        pchild->work_item.mm = mm;
        pchild->work_item.op = op;
        list_add_tail(&pchild->child_list, &prange->child_list);
}

/**
 * svm_range_split_by_granularity - collect ranges within granularity boundary
 *
 * @p: the process with svms list
 * @mm: mm structure
 * @addr: the vm fault address in pages, to split the prange
 * @parent: parent range if prange is from child list
 * @prange: prange to split
 *
 * Trims @prange to be a single aligned block of prange->granularity if
 * possible. The head and tail are added to the child_list in @parent.
 *
 * Context: caller must hold mmap_read_lock and prange->lock
 *
 * Return:
 * 0 - OK, otherwise error code
 */
int
svm_range_split_by_granularity(struct kfd_process *p, struct mm_struct *mm,
                               unsigned long addr, struct svm_range *parent,
                               struct svm_range *prange)
{
        struct svm_range *head, *tail;
        unsigned long start, last, size;
        int r;

        /* Align splited range start and size to granularity size, then a single

         * PTE will be used for whole range, this reduces the number of PTE
         * updated and the L1 TLB space used for translation.
         */
        size = 1UL << prange->granularity;
        start = ALIGN_DOWN(addr, size);
        last = ALIGN(addr + 1, size) - 1;

        pr_debug("svms 0x%p split [0x%lx 0x%lx] to [0x%lx 0x%lx] size 0x%lx\n",
                 prange->svms, prange->start, prange->last, start, last, size);

        if (start > prange->start) {
                r = svm_range_split(prange, start, prange->last, &head);
                if (r)
                        return r;
                svm_range_add_child(parent, mm, head, SVM_OP_ADD_RANGE);
        }

        if (last < prange->last) {
                r = svm_range_split(prange, prange->start, last, &tail);
                if (r)
                        return r;
                svm_range_add_child(parent, mm, tail, SVM_OP_ADD_RANGE);
        }

        /* xnack on, update mapping on GPUs with ACCESS_IN_PLACE */
        if (p->xnack_enabled && prange->work_item.op == SVM_OP_ADD_RANGE) {
                prange->work_item.op = SVM_OP_ADD_RANGE_AND_MAP;
                pr_debug("change prange 0x%p [0x%lx 0x%lx] op %d\n",
                         prange, prange->start, prange->last,
                         SVM_OP_ADD_RANGE_AND_MAP);
        }
        return 0;
}

static uint64_t
svm_range_get_pte_flags(struct amdgpu_device *adev, struct svm_range *prange,
                        int domain)
{
        struct amdgpu_device *bo_adev;
        uint32_t flags = prange->flags;
        uint32_t mapping_flags = 0;
        uint64_t pte_flags;
        bool snoop = (domain != SVM_RANGE_VRAM_DOMAIN);
        bool coherent = flags & KFD_IOCTL_SVM_FLAG_COHERENT;

        if (domain == SVM_RANGE_VRAM_DOMAIN)
                bo_adev = amdgpu_ttm_adev(prange->svm_bo->bo->tbo.bdev);

        switch (adev->asic_type) {
        case CHIP_ARCTURUS:
                if (domain == SVM_RANGE_VRAM_DOMAIN) {
                        if (bo_adev == adev) {
                                mapping_flags |= coherent ?
                                        AMDGPU_VM_MTYPE_CC : AMDGPU_VM_MTYPE_RW;
                        } else {
                                mapping_flags |= coherent ?
                                        AMDGPU_VM_MTYPE_UC : AMDGPU_VM_MTYPE_NC;
                                if (amdgpu_xgmi_same_hive(adev, bo_adev))
                                        snoop = true;
                        }
                } else {
                        mapping_flags |= coherent ?
                                AMDGPU_VM_MTYPE_UC : AMDGPU_VM_MTYPE_NC;
                }
                break;
        case CHIP_ALDEBARAN:
                if (domain == SVM_RANGE_VRAM_DOMAIN) {
                        if (bo_adev == adev) {
                                mapping_flags |= coherent ?
                                        AMDGPU_VM_MTYPE_CC : AMDGPU_VM_MTYPE_RW;
                                if (adev->gmc.xgmi.connected_to_cpu)
                                        snoop = true;
                        } else {
                                mapping_flags |= coherent ?
                                        AMDGPU_VM_MTYPE_UC : AMDGPU_VM_MTYPE_NC;
                                if (amdgpu_xgmi_same_hive(adev, bo_adev))
                                        snoop = true;
                        }
                } else {
                        mapping_flags |= coherent ?
                                AMDGPU_VM_MTYPE_UC : AMDGPU_VM_MTYPE_NC;
                }
                break;
        default:
                mapping_flags |= coherent ?
                        AMDGPU_VM_MTYPE_UC : AMDGPU_VM_MTYPE_NC;
        }

        mapping_flags |= AMDGPU_VM_PAGE_READABLE | AMDGPU_VM_PAGE_WRITEABLE;

        if (flags & KFD_IOCTL_SVM_FLAG_GPU_RO)
                mapping_flags &= ~AMDGPU_VM_PAGE_WRITEABLE;
        if (flags & KFD_IOCTL_SVM_FLAG_GPU_EXEC)
                mapping_flags |= AMDGPU_VM_PAGE_EXECUTABLE;

        pte_flags = AMDGPU_PTE_VALID;
        pte_flags |= (domain == SVM_RANGE_VRAM_DOMAIN) ? 0 : AMDGPU_PTE_SYSTEM;
        pte_flags |= snoop ? AMDGPU_PTE_SNOOPED : 0;

        pte_flags |= amdgpu_gem_va_map_flags(adev, mapping_flags);
        return pte_flags;
}

static int
svm_range_unmap_from_gpu(struct amdgpu_device *adev, struct amdgpu_vm *vm,
                         uint64_t start, uint64_t last,
                         struct dma_fence **fence)
{
        uint64_t init_pte_value = 0;

        pr_debug("[0x%llx 0x%llx]\n", start, last);

        return amdgpu_vm_bo_update_mapping(adev, adev, vm, false, true, NULL,
                                           start, last, init_pte_value, 0,
                                           NULL, NULL, fence, NULL);
}

static int
svm_range_unmap_from_gpus(struct svm_range *prange, unsigned long start,
                          unsigned long last)
{
        DECLARE_BITMAP(bitmap, MAX_GPU_INSTANCE);
        struct kfd_process_device *pdd;
        struct dma_fence *fence = NULL;
        struct amdgpu_device *adev;
        struct kfd_process *p;
        uint32_t gpuidx;
        int r = 0;

        bitmap_or(bitmap, prange->bitmap_access, prange->bitmap_aip,
                  MAX_GPU_INSTANCE);
        p = container_of(prange->svms, struct kfd_process, svms);

        for_each_set_bit(gpuidx, bitmap, MAX_GPU_INSTANCE) {
                pr_debug("unmap from gpu idx 0x%x\n", gpuidx);
                pdd = kfd_process_device_from_gpuidx(p, gpuidx);
                if (!pdd) {
                        pr_debug("failed to find device idx %d\n", gpuidx);
                        return -EINVAL;
                }
                adev = (struct amdgpu_device *)pdd->dev->kgd;

                r = svm_range_unmap_from_gpu(adev, drm_priv_to_vm(pdd->drm_priv),
                                             start, last, &fence);
                if (r)
                        break;

                if (fence) {
                        r = dma_fence_wait(fence, false);
                        dma_fence_put(fence);
                        fence = NULL;
                        if (r)
                                break;
                }
                amdgpu_amdkfd_flush_gpu_tlb_pasid((struct kgd_dev *)adev,
                                        p->pasid, TLB_FLUSH_HEAVYWEIGHT);
        }

        return r;
}

static int
svm_range_map_to_gpu(struct amdgpu_device *adev, struct amdgpu_vm *vm,
                     struct svm_range *prange, unsigned long offset,
                     unsigned long npages, bool readonly, dma_addr_t *dma_addr,
                     struct amdgpu_device *bo_adev, struct dma_fence **fence)
{
        struct amdgpu_bo_va bo_va;
        bool table_freed = false;
        uint64_t pte_flags;
        unsigned long last_start;
        int last_domain;
        int r = 0;
        int64_t i, j;

        last_start = prange->start + offset;

        pr_debug("svms 0x%p [0x%lx 0x%lx] readonly %d\n", prange->svms,
                 last_start, last_start + npages - 1, readonly);

        if (prange->svm_bo && prange->ttm_res)
                bo_va.is_xgmi = amdgpu_xgmi_same_hive(adev, bo_adev);

        for (i = offset; i < offset + npages; i++) {
                last_domain = dma_addr[i] & SVM_RANGE_VRAM_DOMAIN;
                dma_addr[i] &= ~SVM_RANGE_VRAM_DOMAIN;

                /* Collect all pages in the same address range and memory domain
                 * that can be mapped with a single call to update mapping.
                 */
                if (i < offset + npages - 1 &&
                    last_domain == (dma_addr[i + 1] & SVM_RANGE_VRAM_DOMAIN))
                        continue;

                pr_debug("Mapping range [0x%lx 0x%llx] on domain: %s\n",
                         last_start, prange->start + i, last_domain ? "GPU" : "CPU");

                pte_flags = svm_range_get_pte_flags(adev, prange, last_domain);
                if (readonly)
                        pte_flags &= ~AMDGPU_PTE_WRITEABLE;

                pr_debug("svms 0x%p map [0x%lx 0x%llx] vram %d PTE 0x%llx\n",
                         prange->svms, last_start, prange->start + i,
                         (last_domain == SVM_RANGE_VRAM_DOMAIN) ? 1 : 0,
                         pte_flags);

                r = amdgpu_vm_bo_update_mapping(adev, bo_adev, vm, false, false,
                                                NULL, last_start,
                                                prange->start + i, pte_flags,
                                                last_start - prange->start,
                                                NULL, dma_addr,
                                                &vm->last_update,
                                                &table_freed);

                for (j = last_start - prange->start; j <= i; j++)
                        dma_addr[j] |= last_domain;

                if (r) {
                        pr_debug("failed %d to map to gpu 0x%lx\n", r, prange->start);
                        goto out;
                }
                last_start = prange->start + i + 1;
        }

        r = amdgpu_vm_update_pdes(adev, vm, false);
        if (r) {
                pr_debug("failed %d to update directories 0x%lx\n", r,
                         prange->start);
                goto out;
        }

        if (fence)
                *fence = dma_fence_get(vm->last_update);

        if (table_freed) {
                struct kfd_process *p;

                p = container_of(prange->svms, struct kfd_process, svms);
                amdgpu_amdkfd_flush_gpu_tlb_pasid((struct kgd_dev *)adev,
                                                p->pasid, TLB_FLUSH_LEGACY);
        }
out:
        return r;
}

static int
svm_range_map_to_gpus(struct svm_range *prange, unsigned long offset,
                      unsigned long npages, bool readonly,
                      unsigned long *bitmap, bool wait)
{
        struct kfd_process_device *pdd;
        struct amdgpu_device *bo_adev;
        struct amdgpu_device *adev;
        struct kfd_process *p;
        struct dma_fence *fence = NULL;
        uint32_t gpuidx;
        int r = 0;

        if (prange->svm_bo && prange->ttm_res)
                bo_adev = amdgpu_ttm_adev(prange->svm_bo->bo->tbo.bdev);
        else
                bo_adev = NULL;

        p = container_of(prange->svms, struct kfd_process, svms);
        for_each_set_bit(gpuidx, bitmap, MAX_GPU_INSTANCE) {
                pr_debug("mapping to gpu idx 0x%x\n", gpuidx);
                pdd = kfd_process_device_from_gpuidx(p, gpuidx);
                if (!pdd) {
                        pr_debug("failed to find device idx %d\n", gpuidx);
                        return -EINVAL;
                }
                adev = (struct amdgpu_device *)pdd->dev->kgd;

                pdd = kfd_bind_process_to_device(pdd->dev, p);
                if (IS_ERR(pdd))
                        return -EINVAL;

                if (bo_adev && adev != bo_adev &&
                    !amdgpu_xgmi_same_hive(adev, bo_adev)) {
                        pr_debug("cannot map to device idx %d\n", gpuidx);
                        continue;
                }

                r = svm_range_map_to_gpu(adev, drm_priv_to_vm(pdd->drm_priv),
                                         prange, offset, npages, readonly,
                                         prange->dma_addr[gpuidx],
                                         bo_adev, wait ? &fence : NULL);
                if (r)
                        break;

                if (fence) {
                        r = dma_fence_wait(fence, false);
                        dma_fence_put(fence);
                        fence = NULL;
                        if (r) {
                                pr_debug("failed %d to dma fence wait\n", r);
                                break;
                        }
                }
        }

        return r;
}

struct svm_validate_context {
        struct kfd_process *process;
        struct svm_range *prange;
        bool intr;
        unsigned long bitmap[MAX_GPU_INSTANCE];
        struct ttm_validate_buffer tv[MAX_GPU_INSTANCE+1];
        struct list_head validate_list;
        struct ww_acquire_ctx ticket;
};

static int svm_range_reserve_bos(struct svm_validate_context *ctx)
{
        struct kfd_process_device *pdd;
        struct amdgpu_device *adev;
        struct amdgpu_vm *vm;
        uint32_t gpuidx;
        int r;

        INIT_LIST_HEAD(&ctx->validate_list);
        for_each_set_bit(gpuidx, ctx->bitmap, MAX_GPU_INSTANCE) {
                pdd = kfd_process_device_from_gpuidx(ctx->process, gpuidx);
                if (!pdd) {
                        pr_debug("failed to find device idx %d\n", gpuidx);
                        return -EINVAL;
                }
                adev = (struct amdgpu_device *)pdd->dev->kgd;
                vm = drm_priv_to_vm(pdd->drm_priv);

                ctx->tv[gpuidx].bo = &vm->root.bo->tbo;
                ctx->tv[gpuidx].num_shared = 4;
                list_add(&ctx->tv[gpuidx].head, &ctx->validate_list);
        }
        if (ctx->prange->svm_bo && ctx->prange->ttm_res) {
                ctx->tv[MAX_GPU_INSTANCE].bo = &ctx->prange->svm_bo->bo->tbo;
                ctx->tv[MAX_GPU_INSTANCE].num_shared = 1;
                list_add(&ctx->tv[MAX_GPU_INSTANCE].head, &ctx->validate_list);
        }

        r = ttm_eu_reserve_buffers(&ctx->ticket, &ctx->validate_list,
                                   ctx->intr, NULL);
        if (r) {
                pr_debug("failed %d to reserve bo\n", r);
                return r;
        }

        for_each_set_bit(gpuidx, ctx->bitmap, MAX_GPU_INSTANCE) {
                pdd = kfd_process_device_from_gpuidx(ctx->process, gpuidx);
                if (!pdd) {
                        pr_debug("failed to find device idx %d\n", gpuidx);
                        r = -EINVAL;
                        goto unreserve_out;
                }
                adev = (struct amdgpu_device *)pdd->dev->kgd;

                r = amdgpu_vm_validate_pt_bos(adev, drm_priv_to_vm(pdd->drm_priv),
                                              svm_range_bo_validate, NULL);
                if (r) {
                        pr_debug("failed %d validate pt bos\n", r);
                        goto unreserve_out;
                }
        }

        return 0;

unreserve_out:
        ttm_eu_backoff_reservation(&ctx->ticket, &ctx->validate_list);
        return r;
}

static void svm_range_unreserve_bos(struct svm_validate_context *ctx)
{
        ttm_eu_backoff_reservation(&ctx->ticket, &ctx->validate_list);
}

static void *kfd_svm_page_owner(struct kfd_process *p, int32_t gpuidx)
{
        struct kfd_process_device *pdd;
        struct amdgpu_device *adev;

        pdd = kfd_process_device_from_gpuidx(p, gpuidx);
        adev = (struct amdgpu_device *)pdd->dev->kgd;

        return SVM_ADEV_PGMAP_OWNER(adev);
}

/*
 * Validation+GPU mapping with concurrent invalidation (MMU notifiers)
 *
 * To prevent concurrent destruction or change of range attributes, the
 * svm_read_lock must be held. The caller must not hold the svm_write_lock
 * because that would block concurrent evictions and lead to deadlocks. To
 * serialize concurrent migrations or validations of the same range, the
 * prange->migrate_mutex must be held.
 *
 * For VRAM ranges, the SVM BO must be allocated and valid (protected by its
 * eviction fence.
 *
 * The following sequence ensures race-free validation and GPU mapping:
 *
 * 1. Reserve page table (and SVM BO if range is in VRAM)
 * 2. hmm_range_fault to get page addresses (if system memory)
 * 3. DMA-map pages (if system memory)
 * 4-a. Take notifier lock
 * 4-b. Check that pages still valid (mmu_interval_read_retry)
 * 4-c. Check that the range was not split or otherwise invalidated
 * 4-d. Update GPU page table
 * 4.e. Release notifier lock
 * 5. Release page table (and SVM BO) reservation
 */
static int svm_range_validate_and_map(struct mm_struct *mm,
                                      struct svm_range *prange,
                                      int32_t gpuidx, bool intr, bool wait)
{
        struct svm_validate_context ctx;
        unsigned long start, end, addr;
        struct kfd_process *p;
        void *owner;
        int32_t idx;
        int r = 0;

        ctx.process = container_of(prange->svms, struct kfd_process, svms);
        ctx.prange = prange;
        ctx.intr = intr;

        if (gpuidx < MAX_GPU_INSTANCE) {
                bitmap_zero(ctx.bitmap, MAX_GPU_INSTANCE);
                bitmap_set(ctx.bitmap, gpuidx, 1);
        } else if (ctx.process->xnack_enabled) {
                bitmap_copy(ctx.bitmap, prange->bitmap_aip, MAX_GPU_INSTANCE);

                /* If prefetch range to GPU, or GPU retry fault migrate range to
                 * GPU, which has ACCESS attribute to the range, create mapping
                 * on that GPU.
                 */
                if (prange->actual_loc) {
                        gpuidx = kfd_process_gpuidx_from_gpuid(ctx.process,
                                                        prange->actual_loc);
                        if (gpuidx < 0) {
                                WARN_ONCE(1, "failed get device by id 0x%x\n",
                                         prange->actual_loc);
                                return -EINVAL;
                        }
                        if (test_bit(gpuidx, prange->bitmap_access))
                                bitmap_set(ctx.bitmap, gpuidx, 1);
                }
        } else {
                bitmap_or(ctx.bitmap, prange->bitmap_access,
                          prange->bitmap_aip, MAX_GPU_INSTANCE);
        }

        if (bitmap_empty(ctx.bitmap, MAX_GPU_INSTANCE))
                return 0;

        if (prange->actual_loc && !prange->ttm_res) {
                /* This should never happen. actual_loc gets set by
                 * svm_migrate_ram_to_vram after allocating a BO.
                 */
                WARN(1, "VRAM BO missing during validation\n");
                return -EINVAL;
        }

        svm_range_reserve_bos(&ctx);

        p = container_of(prange->svms, struct kfd_process, svms);
        owner = kfd_svm_page_owner(p, find_first_bit(ctx.bitmap,
                                                MAX_GPU_INSTANCE));
        for_each_set_bit(idx, ctx.bitmap, MAX_GPU_INSTANCE) {
                if (kfd_svm_page_owner(p, idx) != owner) {
                        owner = NULL;
                        break;
                }
        }

        start = prange->start << PAGE_SHIFT;
        end = (prange->last + 1) << PAGE_SHIFT;
        for (addr = start; addr < end && !r; ) {
                struct hmm_range *hmm_range;
                struct vm_area_struct *vma;
                unsigned long next;
                unsigned long offset;
                unsigned long npages;
                bool readonly;

                vma = find_vma(mm, addr);
                if (!vma || addr < vma->vm_start) {
                        r = -EFAULT;
                        goto unreserve_out;
                }
                readonly = !(vma->vm_flags & VM_WRITE);

                next = min(vma->vm_end, end);
                npages = (next - addr) >> PAGE_SHIFT;
                r = amdgpu_hmm_range_get_pages(&prange->notifier, mm, NULL,
                                               addr, npages, &hmm_range,
                                               readonly, true, owner);
                if (r) {
                        pr_debug("failed %d to get svm range pages\n", r);
                        goto unreserve_out;
                }

                offset = (addr - start) >> PAGE_SHIFT;
                r = svm_range_dma_map(prange, ctx.bitmap, offset, npages,
                                      hmm_range->hmm_pfns);
                if (r) {
                        pr_debug("failed %d to dma map range\n", r);
                        goto unreserve_out;
                }

                svm_range_lock(prange);
                if (amdgpu_hmm_range_get_pages_done(hmm_range)) {
                        pr_debug("hmm update the range, need validate again\n");
                        r = -EAGAIN;
                        goto unlock_out;
                }
                if (!list_empty(&prange->child_list)) {
                        pr_debug("range split by unmap in parallel, validate again\n");
                        r = -EAGAIN;
                        goto unlock_out;
                }

                r = svm_range_map_to_gpus(prange, offset, npages, readonly,
                                          ctx.bitmap, wait);

unlock_out:
                svm_range_unlock(prange);

                addr = next;
        }

        if (addr == end)
                prange->validated_once = true;

unreserve_out:
        svm_range_unreserve_bos(&ctx);

        if (!r)
                prange->validate_timestamp = ktime_to_us(ktime_get());

        return r;
}

/**
 * svm_range_list_lock_and_flush_work - flush pending deferred work
 *
 * @svms: the svm range list
 * @mm: the mm structure
 *
 * Context: Returns with mmap write lock held, pending deferred work flushed
 *
 */
static void
svm_range_list_lock_and_flush_work(struct svm_range_list *svms,
                                   struct mm_struct *mm)
{
retry_flush_work:
        flush_work(&svms->deferred_list_work);
        mmap_write_lock(mm);

        if (list_empty(&svms->deferred_range_list))
                return;
        mmap_write_unlock(mm);
        pr_debug("retry flush\n");
        goto retry_flush_work;
}

static void svm_range_restore_work(struct work_struct *work)
{
        struct delayed_work *dwork = to_delayed_work(work);
        struct amdkfd_process_info *process_info;
        struct svm_range_list *svms;
        struct svm_range *prange;
        struct kfd_process *p;
        struct mm_struct *mm;
        int evicted_ranges;
        int invalid;
        int r;

        svms = container_of(dwork, struct svm_range_list, restore_work);
        evicted_ranges = atomic_read(&svms->evicted_ranges);
        if (!evicted_ranges)
                return;

        pr_debug("restore svm ranges\n");

        /* kfd_process_notifier_release destroys this worker thread. So during
         * the lifetime of this thread, kfd_process and mm will be valid.
         */
        p = container_of(svms, struct kfd_process, svms);
        process_info = p->kgd_process_info;
        mm = p->mm;
        if (!mm)
                return;

        mutex_lock(&process_info->lock);
        svm_range_list_lock_and_flush_work(svms, mm);
        mutex_lock(&svms->lock);

        evicted_ranges = atomic_read(&svms->evicted_ranges);

        list_for_each_entry(prange, &svms->list, list) {
                invalid = atomic_read(&prange->invalid);
                if (!invalid)
                        continue;

                pr_debug("restoring svms 0x%p prange 0x%p [0x%lx %lx] inv %d\n",
                         prange->svms, prange, prange->start, prange->last,
                         invalid);

                /*
                 * If range is migrating, wait for migration is done.
                 */
                mutex_lock(&prange->migrate_mutex);

                r = svm_range_validate_and_map(mm, prange, MAX_GPU_INSTANCE,
                                               false, true);
                if (r)
                        pr_debug("failed %d to map 0x%lx to gpus\n", r,
                                 prange->start);

                mutex_unlock(&prange->migrate_mutex);
                if (r)
                        goto out_reschedule;

                if (atomic_cmpxchg(&prange->invalid, invalid, 0) != invalid)
                        goto out_reschedule;
        }

        if (atomic_cmpxchg(&svms->evicted_ranges, evicted_ranges, 0) !=
            evicted_ranges)
                goto out_reschedule;

        evicted_ranges = 0;

        r = kgd2kfd_resume_mm(mm);
        if (r) {
                /* No recovery from this failure. Probably the CP is
                 * hanging. No point trying again.
                 */
                pr_debug("failed %d to resume KFD\n", r);
        }

        pr_debug("restore svm ranges successfully\n");

out_reschedule:
        mutex_unlock(&svms->lock);
        mmap_write_unlock(mm);
        mutex_unlock(&process_info->lock);

        /* If validation failed, reschedule another attempt */
        if (evicted_ranges) {
                pr_debug("reschedule to restore svm range\n");
                schedule_delayed_work(&svms->restore_work,
                        msecs_to_jiffies(AMDGPU_SVM_RANGE_RESTORE_DELAY_MS));
        }
}

/**
 * svm_range_evict - evict svm range
 *
 * Stop all queues of the process to ensure GPU doesn't access the memory, then
 * return to let CPU evict the buffer and proceed CPU pagetable update.
 *
 * Don't need use lock to sync cpu pagetable invalidation with GPU execution.
 * If invalidation happens while restore work is running, restore work will
 * restart to ensure to get the latest CPU pages mapping to GPU, then start
 * the queues.
 */
static int
svm_range_evict(struct svm_range *prange, struct mm_struct *mm,
                unsigned long start, unsigned long last)
{
        struct svm_range_list *svms = prange->svms;
        struct svm_range *pchild;
        struct kfd_process *p;
        int r = 0;

        p = container_of(svms, struct kfd_process, svms);

        pr_debug("invalidate svms 0x%p prange [0x%lx 0x%lx] [0x%lx 0x%lx]\n",
                 svms, prange->start, prange->last, start, last);

        if (!p->xnack_enabled) {
                int evicted_ranges;

                list_for_each_entry(pchild, &prange->child_list, child_list) {
                        mutex_lock_nested(&pchild->lock, 1);
                        if (pchild->start <= last && pchild->last >= start) {
                                pr_debug("increment pchild invalid [0x%lx 0x%lx]\n",
                                         pchild->start, pchild->last);
                                atomic_inc(&pchild->invalid);
                        }
                        mutex_unlock(&pchild->lock);
                }

                if (prange->start <= last && prange->last >= start)
                        atomic_inc(&prange->invalid);

                evicted_ranges = atomic_inc_return(&svms->evicted_ranges);
                if (evicted_ranges != 1)
                        return r;

                pr_debug("evicting svms 0x%p range [0x%lx 0x%lx]\n",
                         prange->svms, prange->start, prange->last);

                /* First eviction, stop the queues */
                r = kgd2kfd_quiesce_mm(mm);
                if (r)
                        pr_debug("failed to quiesce KFD\n");

                pr_debug("schedule to restore svm %p ranges\n", svms);
                schedule_delayed_work(&svms->restore_work,
                        msecs_to_jiffies(AMDGPU_SVM_RANGE_RESTORE_DELAY_MS));
        } else {
                unsigned long s, l;

                pr_debug("invalidate unmap svms 0x%p [0x%lx 0x%lx] from GPUs\n",
                         prange->svms, start, last);
                list_for_each_entry(pchild, &prange->child_list, child_list) {
                        mutex_lock_nested(&pchild->lock, 1);
                        s = max(start, pchild->start);
                        l = min(last, pchild->last);
                        if (l >= s)
                                svm_range_unmap_from_gpus(pchild, s, l);
                        mutex_unlock(&pchild->lock);
                }
                s = max(start, prange->start);
                l = min(last, prange->last);
                if (l >= s)
                        svm_range_unmap_from_gpus(prange, s, l);
        }

        return r;
}

static struct svm_range *svm_range_clone(struct svm_range *old)
{
        struct svm_range *new;

        new = svm_range_new(old->svms, old->start, old->last);
        if (!new)
                return NULL;

        if (old->svm_bo) {
                new->ttm_res = old->ttm_res;
                new->offset = old->offset;
                new->svm_bo = svm_range_bo_ref(old->svm_bo);
                spin_lock(&new->svm_bo->list_lock);
                list_add(&new->svm_bo_list, &new->svm_bo->range_list);
                spin_unlock(&new->svm_bo->list_lock);
        }
        new->flags = old->flags;
        new->preferred_loc = old->preferred_loc;
        new->prefetch_loc = old->prefetch_loc;
        new->actual_loc = old->actual_loc;
        new->granularity = old->granularity;
        bitmap_copy(new->bitmap_access, old->bitmap_access, MAX_GPU_INSTANCE);
        bitmap_copy(new->bitmap_aip, old->bitmap_aip, MAX_GPU_INSTANCE);

        return new;
}

/**
 * svm_range_handle_overlap - split overlap ranges
 * @svms: svm range list header
 * @new: range added with this attributes
 * @start: range added start address, in pages
 * @last: range last address, in pages
 * @update_list: output, the ranges attributes are updated. For set_attr, this
 *               will do validation and map to GPUs. For unmap, this will be
 *               removed and unmap from GPUs
 * @insert_list: output, the ranges will be inserted into svms, attributes are
 *               not changes. For set_attr, this will add into svms.
 * @remove_list:output, the ranges will be removed from svms
 * @left: the remaining range after overlap, For set_attr, this will be added
 *        as new range.
 *
 * Total have 5 overlap cases.
 *
 * This function handles overlap of an address interval with existing
 * struct svm_ranges for applying new attributes. This may require
 * splitting existing struct svm_ranges. All changes should be applied to
 * the range_list and interval tree transactionally. If any split operation
 * fails, the entire update fails. Therefore the existing overlapping
 * svm_ranges are cloned and the original svm_ranges left unchanged. If the
 * transaction succeeds, the modified clones are added and the originals
 * freed. Otherwise the clones are removed and the old svm_ranges remain.
 *
 * Context: The caller must hold svms->lock
 */
static int
svm_range_handle_overlap(struct svm_range_list *svms, struct svm_range *new,
                         unsigned long start, unsigned long last,
                         struct list_head *update_list,
                         struct list_head *insert_list,
                         struct list_head *remove_list,
                         unsigned long *left)
{
        struct interval_tree_node *node;
        struct svm_range *prange;
        struct svm_range *tmp;
        int r = 0;

        INIT_LIST_HEAD(update_list);
        INIT_LIST_HEAD(insert_list);
        INIT_LIST_HEAD(remove_list);

        node = interval_tree_iter_first(&svms->objects, start, last);
        while (node) {
                struct interval_tree_node *next;
                struct svm_range *old;
                unsigned long next_start;

                pr_debug("found overlap node [0x%lx 0x%lx]\n", node->start,
                         node->last);

                old = container_of(node, struct svm_range, it_node);
                next = interval_tree_iter_next(node, start, last);
                next_start = min(node->last, last) + 1;

                if (node->start < start || node->last > last) {
                        /* node intersects the updated range, clone+split it */
                        prange = svm_range_clone(old);
                        if (!prange) {
                                r = -ENOMEM;
                                goto out;
                        }

                        list_add(&old->remove_list, remove_list);
                        list_add(&prange->insert_list, insert_list);

                        if (node->start < start) {
                                pr_debug("change old range start\n");
                                r = svm_range_split_head(prange, new, start,
                                                         insert_list);
                                if (r)
                                        goto out;
                        }
                        if (node->last > last) {
                                pr_debug("change old range last\n");
                                r = svm_range_split_tail(prange, new, last,
                                                         insert_list);
                                if (r)
                                        goto out;
                        }
                } else {
                        /* The node is contained within start..last,
                         * just update it
                         */
                        prange = old;
                }

                if (!svm_range_is_same_attrs(prange, new))
                        list_add(&prange->update_list, update_list);

                /* insert a new node if needed */
                if (node->start > start) {
                        prange = svm_range_new(prange->svms, start,
                                               node->start - 1);
                        if (!prange) {
                                r = -ENOMEM;
                                goto out;
                        }

                        list_add(&prange->insert_list, insert_list);
                        list_add(&prange->update_list, update_list);
                }

                node = next;
                start = next_start;
        }

        if (left && start <= last)
                *left = last - start + 1;

out:
        if (r)
                list_for_each_entry_safe(prange, tmp, insert_list, insert_list)
                        svm_range_free(prange);

        return r;
}

static void
svm_range_update_notifier_and_interval_tree(struct mm_struct *mm,
                                            struct svm_range *prange)
{
        unsigned long start;
        unsigned long last;

        start = prange->notifier.interval_tree.start >> PAGE_SHIFT;
        last = prange->notifier.interval_tree.last >> PAGE_SHIFT;

        if (prange->start == start && prange->last == last)
                return;

        pr_debug("up notifier 0x%p prange 0x%p [0x%lx 0x%lx] [0x%lx 0x%lx]\n",
                  prange->svms, prange, start, last, prange->start,
                  prange->last);

        if (start != 0 && last != 0) {
                interval_tree_remove(&prange->it_node, &prange->svms->objects);
                svm_range_remove_notifier(prange);
        }
        prange->it_node.start = prange->start;
        prange->it_node.last = prange->last;

        interval_tree_insert(&prange->it_node, &prange->svms->objects);
        svm_range_add_notifier_locked(mm, prange);
}

static void
svm_range_handle_list_op(struct svm_range_list *svms, struct svm_range *prange)
{
        struct mm_struct *mm = prange->work_item.mm;

        switch (prange->work_item.op) {
        case SVM_OP_NULL:
                pr_debug("NULL OP 0x%p prange 0x%p [0x%lx 0x%lx]\n",
                         svms, prange, prange->start, prange->last);
                break;
        case SVM_OP_UNMAP_RANGE:
                pr_debug("remove 0x%p prange 0x%p [0x%lx 0x%lx]\n",
                         svms, prange, prange->start, prange->last);
                svm_range_unlink(prange);
                svm_range_remove_notifier(prange);
                svm_range_free(prange);
                break;
        case SVM_OP_UPDATE_RANGE_NOTIFIER:
                pr_debug("update notifier 0x%p prange 0x%p [0x%lx 0x%lx]\n",
                         svms, prange, prange->start, prange->last);
                svm_range_update_notifier_and_interval_tree(mm, prange);
                break;
        case SVM_OP_UPDATE_RANGE_NOTIFIER_AND_MAP:
                pr_debug("update and map 0x%p prange 0x%p [0x%lx 0x%lx]\n",
                         svms, prange, prange->start, prange->last);
                svm_range_update_notifier_and_interval_tree(mm, prange);
                /* TODO: implement deferred validation and mapping */
                break;
        case SVM_OP_ADD_RANGE:
                pr_debug("add 0x%p prange 0x%p [0x%lx 0x%lx]\n", svms, prange,
                         prange->start, prange->last);
                svm_range_add_to_svms(prange);
                svm_range_add_notifier_locked(mm, prange);
                break;
        case SVM_OP_ADD_RANGE_AND_MAP:
                pr_debug("add and map 0x%p prange 0x%p [0x%lx 0x%lx]\n", svms,
                         prange, prange->start, prange->last);
                svm_range_add_to_svms(prange);
                svm_range_add_notifier_locked(mm, prange);
                /* TODO: implement deferred validation and mapping */
                break;
        default:
                WARN_ONCE(1, "Unknown prange 0x%p work op %d\n", prange,
                         prange->work_item.op);
        }
}

static void svm_range_drain_retry_fault(struct svm_range_list *svms)
{
        struct kfd_process_device *pdd;
        struct amdgpu_device *adev;
        struct kfd_process *p;
        uint32_t i;

        p = container_of(svms, struct kfd_process, svms);

        for_each_set_bit(i, svms->bitmap_supported, p->n_pdds) {
                pdd = p->pdds[i];
                if (!pdd)
                        continue;

                pr_debug("drain retry fault gpu %d svms %p\n", i, svms);
                adev = (struct amdgpu_device *)pdd->dev->kgd;

                amdgpu_ih_wait_on_checkpoint_process(adev, &adev->irq.ih1);
                pr_debug("drain retry fault gpu %d svms 0x%p done\n", i, svms);
        }
}

static void svm_range_deferred_list_work(struct work_struct *work)
{
        struct svm_range_list *svms;
        struct svm_range *prange;
        struct mm_struct *mm;

        svms = container_of(work, struct svm_range_list, deferred_list_work);
        pr_debug("enter svms 0x%p\n", svms);

        spin_lock(&svms->deferred_list_lock);
        while (!list_empty(&svms->deferred_range_list)) {
                prange = list_first_entry(&svms->deferred_range_list,
                                          struct svm_range, deferred_list);
                spin_unlock(&svms->deferred_list_lock);
                pr_debug("prange 0x%p [0x%lx 0x%lx] op %d\n", prange,
                         prange->start, prange->last, prange->work_item.op);

                /* Make sure no stale retry fault coming after range is freed */
                if (prange->work_item.op == SVM_OP_UNMAP_RANGE)
                        svm_range_drain_retry_fault(prange->svms);

                mm = prange->work_item.mm;
                mmap_write_lock(mm);
                mutex_lock(&svms->lock);

                /* Remove from deferred_list must be inside mmap write lock,
                 * otherwise, svm_range_list_lock_and_flush_work may hold mmap
                 * write lock, and continue because deferred_list is empty, then
                 * deferred_list handle is blocked by mmap write lock.
                 */
                spin_lock(&svms->deferred_list_lock);
                list_del_init(&prange->deferred_list);
                spin_unlock(&svms->deferred_list_lock);

                mutex_lock(&prange->migrate_mutex);
                while (!list_empty(&prange->child_list)) {
                        struct svm_range *pchild;

                        pchild = list_first_entry(&prange->child_list,
                                                struct svm_range, child_list);
                        pr_debug("child prange 0x%p op %d\n", pchild,
                                 pchild->work_item.op);
                        list_del_init(&pchild->child_list);
                        svm_range_handle_list_op(svms, pchild);
                }
                mutex_unlock(&prange->migrate_mutex);

                svm_range_handle_list_op(svms, prange);
                mutex_unlock(&svms->lock);
                mmap_write_unlock(mm);

                spin_lock(&svms->deferred_list_lock);
        }
        spin_unlock(&svms->deferred_list_lock);

        pr_debug("exit svms 0x%p\n", svms);
}

void
svm_range_add_list_work(struct svm_range_list *svms, struct svm_range *prange,
                        struct mm_struct *mm, enum svm_work_list_ops op)
{
        spin_lock(&svms->deferred_list_lock);
        /* if prange is on the deferred list */
        if (!list_empty(&prange->deferred_list)) {
                pr_debug("update exist prange 0x%p work op %d\n", prange, op);
                WARN_ONCE(prange->work_item.mm != mm, "unmatch mm\n");
                if (op != SVM_OP_NULL &&
                    prange->work_item.op != SVM_OP_UNMAP_RANGE)
                        prange->work_item.op = op;
        } else {
                prange->work_item.op = op;
                prange->work_item.mm = mm;
                list_add_tail(&prange->deferred_list,
                              &prange->svms->deferred_range_list);
                pr_debug("add prange 0x%p [0x%lx 0x%lx] to work list op %d\n",
                         prange, prange->start, prange->last, op);
        }
        spin_unlock(&svms->deferred_list_lock);
}

void schedule_deferred_list_work(struct svm_range_list *svms)
{
        spin_lock(&svms->deferred_list_lock);
        if (!list_empty(&svms->deferred_range_list))
                schedule_work(&svms->deferred_list_work);
        spin_unlock(&svms->deferred_list_lock);
}

static void
svm_range_unmap_split(struct mm_struct *mm, struct svm_range *parent,
                      struct svm_range *prange, unsigned long start,
                      unsigned long last)
{
        struct svm_range *head;
        struct svm_range *tail;

        if (prange->work_item.op == SVM_OP_UNMAP_RANGE) {
                pr_debug("prange 0x%p [0x%lx 0x%lx] is already freed\n", prange,
                         prange->start, prange->last);
                return;
        }
        if (start > prange->last || last < prange->start)
                return;

        head = tail = prange;
        if (start > prange->start)
                svm_range_split(prange, prange->start, start - 1, &tail);
        if (last < tail->last)
                svm_range_split(tail, last + 1, tail->last, &head);

        if (head != prange && tail != prange) {
                svm_range_add_child(parent, mm, head, SVM_OP_UNMAP_RANGE);
                svm_range_add_child(parent, mm, tail, SVM_OP_ADD_RANGE);
        } else if (tail != prange) {
                svm_range_add_child(parent, mm, tail, SVM_OP_UNMAP_RANGE);
        } else if (head != prange) {
                svm_range_add_child(parent, mm, head, SVM_OP_UNMAP_RANGE);
        } else if (parent != prange) {
                prange->work_item.op = SVM_OP_UNMAP_RANGE;
        }
}

static void
svm_range_unmap_from_cpu(struct mm_struct *mm, struct svm_range *prange,
                         unsigned long start, unsigned long last)
{
        struct svm_range_list *svms;
        struct svm_range *pchild;
        struct kfd_process *p;
        unsigned long s, l;
        bool unmap_parent;

        p = kfd_lookup_process_by_mm(mm);
        if (!p)
                return;
        svms = &p->svms;

        pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx] [0x%lx 0x%lx]\n", svms,
                 prange, prange->start, prange->last, start, last);

        unmap_parent = start <= prange->start && last >= prange->last;

        list_for_each_entry(pchild, &prange->child_list, child_list) {
                mutex_lock_nested(&pchild->lock, 1);
                s = max(start, pchild->start);
                l = min(last, pchild->last);
                if (l >= s)
                        svm_range_unmap_from_gpus(pchild, s, l);
                svm_range_unmap_split(mm, prange, pchild, start, last);
                mutex_unlock(&pchild->lock);
        }
        s = max(start, prange->start);
        l = min(last, prange->last);
        if (l >= s)
                svm_range_unmap_from_gpus(prange, s, l);
        svm_range_unmap_split(mm, prange, prange, start, last);

        if (unmap_parent)
                svm_range_add_list_work(svms, prange, mm, SVM_OP_UNMAP_RANGE);
        else
                svm_range_add_list_work(svms, prange, mm,
                                        SVM_OP_UPDATE_RANGE_NOTIFIER);
        schedule_deferred_list_work(svms);

        kfd_unref_process(p);
}

/**
 * svm_range_cpu_invalidate_pagetables - interval notifier callback
 *
 * If event is MMU_NOTIFY_UNMAP, this is from CPU unmap range, otherwise, it
 * is from migration, or CPU page invalidation callback.
 *
 * For unmap event, unmap range from GPUs, remove prange from svms in a delayed
 * work thread, and split prange if only part of prange is unmapped.
 *
 * For invalidation event, if GPU retry fault is not enabled, evict the queues,
 * then schedule svm_range_restore_work to update GPU mapping and resume queues.
 * If GPU retry fault is enabled, unmap the svm range from GPU, retry fault will
 * update GPU mapping to recover.
 *
 * Context: mmap lock, notifier_invalidate_start lock are held
 *          for invalidate event, prange lock is held if this is from migration
 */
static bool
svm_range_cpu_invalidate_pagetables(struct mmu_interval_notifier *mni,
                                    const struct mmu_notifier_range *range,
                                    unsigned long cur_seq)
{
        struct svm_range *prange;
        unsigned long start;
        unsigned long last;

        if (range->event == MMU_NOTIFY_RELEASE)
                return true;

        start = mni->interval_tree.start;
        last = mni->interval_tree.last;
        start = (start > range->start ? start : range->start) >> PAGE_SHIFT;
        last = (last < (range->end - 1) ? last : range->end - 1) >> PAGE_SHIFT;
        pr_debug("[0x%lx 0x%lx] range[0x%lx 0x%lx] notifier[0x%lx 0x%lx] %d\n",
                 start, last, range->start >> PAGE_SHIFT,
                 (range->end - 1) >> PAGE_SHIFT,
                 mni->interval_tree.start >> PAGE_SHIFT,
                 mni->interval_tree.last >> PAGE_SHIFT, range->event);

        prange = container_of(mni, struct svm_range, notifier);

        svm_range_lock(prange);
        mmu_interval_set_seq(mni, cur_seq);

        switch (range->event) {
        case MMU_NOTIFY_UNMAP:
                svm_range_unmap_from_cpu(mni->mm, prange, start, last);
                break;
        default:
                svm_range_evict(prange, mni->mm, start, last);
                break;
        }

        svm_range_unlock(prange);

        return true;
}

/**
 * svm_range_from_addr - find svm range from fault address
 * @svms: svm range list header
 * @addr: address to search range interval tree, in pages
 * @parent: parent range if range is on child list
 *
 * Context: The caller must hold svms->lock
 *
 * Return: the svm_range found or NULL
 */
struct svm_range *
svm_range_from_addr(struct svm_range_list *svms, unsigned long addr,
                    struct svm_range **parent)
{
        struct interval_tree_node *node;
        struct svm_range *prange;
        struct svm_range *pchild;

        node = interval_tree_iter_first(&svms->objects, addr, addr);
        if (!node)
                return NULL;

        prange = container_of(node, struct svm_range, it_node);
        pr_debug("address 0x%lx prange [0x%lx 0x%lx] node [0x%lx 0x%lx]\n",
                 addr, prange->start, prange->last, node->start, node->last);

        if (addr >= prange->start && addr <= prange->last) {
                if (parent)
                        *parent = prange;
                return prange;
        }
        list_for_each_entry(pchild, &prange->child_list, child_list)
                if (addr >= pchild->start && addr <= pchild->last) {
                        pr_debug("found address 0x%lx pchild [0x%lx 0x%lx]\n",
                                 addr, pchild->start, pchild->last);
                        if (parent)
                                *parent = prange;
                        return pchild;
                }

        return NULL;
}

/* svm_range_best_restore_location - decide the best fault restore location
 * @prange: svm range structure
 * @adev: the GPU on which vm fault happened
 *
 * This is only called when xnack is on, to decide the best location to restore
 * the range mapping after GPU vm fault. Caller uses the best location to do
 * migration if actual loc is not best location, then update GPU page table
 * mapping to the best location.
 *
 * If vm fault gpu is range preferred loc, the best_loc is preferred loc.
 * If vm fault gpu idx is on range ACCESSIBLE bitmap, best_loc is vm fault gpu
 * If vm fault gpu idx is on range ACCESSIBLE_IN_PLACE bitmap, then
 *    if range actual loc is cpu, best_loc is cpu
 *    if vm fault gpu is on xgmi same hive of range actual loc gpu, best_loc is
 *    range actual loc.
 * Otherwise, GPU no access, best_loc is -1.
 *
 * Return:
 * -1 means vm fault GPU no access
 * 0 for CPU or GPU id
 */
static int32_t
svm_range_best_restore_location(struct svm_range *prange,
                                struct amdgpu_device *adev,
                                int32_t *gpuidx)
{
        struct amdgpu_device *bo_adev;
        struct kfd_process *p;
        uint32_t gpuid;
        int r;

        p = container_of(prange->svms, struct kfd_process, svms);

        r = kfd_process_gpuid_from_kgd(p, adev, &gpuid, gpuidx);
        if (r < 0) {
                pr_debug("failed to get gpuid from kgd\n");
                return -1;
        }

        if (prange->preferred_loc == gpuid)
                return prange->preferred_loc;

        if (test_bit(*gpuidx, prange->bitmap_access))
                return gpuid;

        if (test_bit(*gpuidx, prange->bitmap_aip)) {
                if (!prange->actual_loc)
                        return 0;

                bo_adev = svm_range_get_adev_by_id(prange, prange->actual_loc);
                if (amdgpu_xgmi_same_hive(adev, bo_adev))
                        return prange->actual_loc;
                else
                        return 0;
        }

        return -1;
}
static int
svm_range_get_range_boundaries(struct kfd_process *p, int64_t addr,
                                unsigned long *start, unsigned long *last)
{
        struct vm_area_struct *vma;
        struct interval_tree_node *node;
        unsigned long start_limit, end_limit;

        vma = find_vma(p->mm, addr << PAGE_SHIFT);
        if (!vma || (addr << PAGE_SHIFT) < vma->vm_start) {
                pr_debug("VMA does not exist in address [0x%llx]\n", addr);
                return -EFAULT;
        }
        start_limit = max(vma->vm_start >> PAGE_SHIFT,
                      (unsigned long)ALIGN_DOWN(addr, 2UL << 8));
        end_limit = min(vma->vm_end >> PAGE_SHIFT,
                    (unsigned long)ALIGN(addr + 1, 2UL << 8));
        /* First range that starts after the fault address */
        node = interval_tree_iter_first(&p->svms.objects, addr + 1, ULONG_MAX);
        if (node) {
                end_limit = min(end_limit, node->start);
                /* Last range that ends before the fault address */
                node = container_of(rb_prev(&node->rb),
                                    struct interval_tree_node, rb);
        } else {
                /* Last range must end before addr because
                 * there was no range after addr
                 */
                node = container_of(rb_last(&p->svms.objects.rb_root),
                                    struct interval_tree_node, rb);
        }
        if (node) {
                if (node->last >= addr) {
                        WARN(1, "Overlap with prev node and page fault addr\n");
                        return -EFAULT;
                }
                start_limit = max(start_limit, node->last + 1);
        }

        *start = start_limit;
        *last = end_limit - 1;

        pr_debug("vma start: 0x%lx start: 0x%lx vma end: 0x%lx last: 0x%lx\n",
                  vma->vm_start >> PAGE_SHIFT, *start,
                  vma->vm_end >> PAGE_SHIFT, *last);

        return 0;

}
static struct
svm_range *svm_range_create_unregistered_range(struct amdgpu_device *adev,
                                                struct kfd_process *p,
                                                struct mm_struct *mm,
                                                int64_t addr)
{
        struct svm_range *prange = NULL;
        unsigned long start, last;
        uint32_t gpuid, gpuidx;

        if (svm_range_get_range_boundaries(p, addr, &start, &last))
                return NULL;

        prange = svm_range_new(&p->svms, start, last);
        if (!prange) {
                pr_debug("Failed to create prange in address [0x%llx]\n", addr);
                return NULL;
        }
        if (kfd_process_gpuid_from_kgd(p, adev, &gpuid, &gpuidx)) {
                pr_debug("failed to get gpuid from kgd\n");
                svm_range_free(prange);
                return NULL;
        }

        svm_range_add_to_svms(prange);
        svm_range_add_notifier_locked(mm, prange);

        return prange;
}

/* svm_range_skip_recover - decide if prange can be recovered
 * @prange: svm range structure
 *
 * GPU vm retry fault handle skip recover the range for cases:
 * 1. prange is on deferred list to be removed after unmap, it is stale fault,
 *    deferred list work will drain the stale fault before free the prange.
 * 2. prange is on deferred list to add interval notifier after split, or
 * 3. prange is child range, it is split from parent prange, recover later
 *    after interval notifier is added.
 *
 * Return: true to skip recover, false to recover
 */
static bool svm_range_skip_recover(struct svm_range *prange)
{
        struct svm_range_list *svms = prange->svms;

        spin_lock(&svms->deferred_list_lock);
        if (list_empty(&prange->deferred_list) &&
            list_empty(&prange->child_list)) {
                spin_unlock(&svms->deferred_list_lock);
                return false;
        }
        spin_unlock(&svms->deferred_list_lock);

        if (prange->work_item.op == SVM_OP_UNMAP_RANGE) {
                pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx] unmapped\n",
                         svms, prange, prange->start, prange->last);
                return true;
        }
        if (prange->work_item.op == SVM_OP_ADD_RANGE_AND_MAP ||
            prange->work_item.op == SVM_OP_ADD_RANGE) {
                pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx] not added yet\n",
                         svms, prange, prange->start, prange->last);
                return true;
        }
        return false;
}

static void
svm_range_count_fault(struct amdgpu_device *adev, struct kfd_process *p,
                      int32_t gpuidx)
{
        struct kfd_process_device *pdd;

        /* fault is on different page of same range
         * or fault is skipped to recover later
         * or fault is on invalid virtual address
         */
        if (gpuidx == MAX_GPU_INSTANCE) {
                uint32_t gpuid;
                int r;

                r = kfd_process_gpuid_from_kgd(p, adev, &gpuid, &gpuidx);
                if (r < 0)
                        return;
        }

        /* fault is recovered
         * or fault cannot recover because GPU no access on the range
         */
        pdd = kfd_process_device_from_gpuidx(p, gpuidx);
        if (pdd)
                WRITE_ONCE(pdd->faults, pdd->faults + 1);
}

static bool
svm_fault_allowed(struct mm_struct *mm, uint64_t addr, bool write_fault)
{
        unsigned long requested = VM_READ;
        struct vm_area_struct *vma;

        if (write_fault)
                requested |= VM_WRITE;

        vma = find_vma(mm, addr << PAGE_SHIFT);
        if (!vma || (addr << PAGE_SHIFT) < vma->vm_start) {
                pr_debug("address 0x%llx VMA is removed\n", addr);
                return true;
        }

        pr_debug("requested 0x%lx, vma permission flags 0x%lx\n", requested,
                vma->vm_flags);
        return (vma->vm_flags & requested) == requested;
}

int
svm_range_restore_pages(struct amdgpu_device *adev, unsigned int pasid,
                        uint64_t addr, bool write_fault)
{
        struct mm_struct *mm = NULL;
        struct svm_range_list *svms;
        struct svm_range *prange;
        struct kfd_process *p;
        uint64_t timestamp;
        int32_t best_loc;
        int32_t gpuidx = MAX_GPU_INSTANCE;
        bool write_locked = false;
        int r = 0;

        if (!KFD_IS_SVM_API_SUPPORTED(adev->kfd.dev)) {
                pr_debug("device does not support SVM\n");
                return -EFAULT;
        }

        p = kfd_lookup_process_by_pasid(pasid);
        if (!p) {
                pr_debug("kfd process not founded pasid 0x%x\n", pasid);
                return -ESRCH;
        }
        if (!p->xnack_enabled) {
                pr_debug("XNACK not enabled for pasid 0x%x\n", pasid);
                r = -EFAULT;
                goto out;
        }
        svms = &p->svms;

        pr_debug("restoring svms 0x%p fault address 0x%llx\n", svms, addr);

        mm = get_task_mm(p->lead_thread);
        if (!mm) {
                pr_debug("svms 0x%p failed to get mm\n", svms);
                r = -ESRCH;
                goto out;
        }

        mmap_read_lock(mm);
retry_write_locked:
        mutex_lock(&svms->lock);
        prange = svm_range_from_addr(svms, addr, NULL);
        if (!prange) {
                pr_debug("failed to find prange svms 0x%p address [0x%llx]\n",
                         svms, addr);
                if (!write_locked) {
                        /* Need the write lock to create new range with MMU notifier.
                         * Also flush pending deferred work to make sure the interval
                         * tree is up to date before we add a new range
                         */
                        mutex_unlock(&svms->lock);
                        mmap_read_unlock(mm);
                        mmap_write_lock(mm);
                        write_locked = true;
                        goto retry_write_locked;
                }
                prange = svm_range_create_unregistered_range(adev, p, mm, addr);
                if (!prange) {
                        pr_debug("failed to create unregistered range svms 0x%p address [0x%llx]\n",
                                 svms, addr);
                        mmap_write_downgrade(mm);
                        r = -EFAULT;
                        goto out_unlock_svms;
                }
        }
        if (write_locked)
                mmap_write_downgrade(mm);

        mutex_lock(&prange->migrate_mutex);

        if (svm_range_skip_recover(prange)) {
                amdgpu_gmc_filter_faults_remove(adev, addr, pasid);
                goto out_unlock_range;
        }

        timestamp = ktime_to_us(ktime_get()) - prange->validate_timestamp;
        /* skip duplicate vm fault on different pages of same range */
        if (timestamp < AMDGPU_SVM_RANGE_RETRY_FAULT_PENDING) {
                pr_debug("svms 0x%p [0x%lx %lx] already restored\n",
                         svms, prange->start, prange->last);
                goto out_unlock_range;
        }

        if (!svm_fault_allowed(mm, addr, write_fault)) {
                pr_debug("fault addr 0x%llx no %s permission\n", addr,
                        write_fault ? "write" : "read");
                r = -EPERM;
                goto out_unlock_range;
        }

        best_loc = svm_range_best_restore_location(prange, adev, &gpuidx);
        if (best_loc == -1) {
                pr_debug("svms %p failed get best restore loc [0x%lx 0x%lx]\n",
                         svms, prange->start, prange->last);
                r = -EACCES;
                goto out_unlock_range;
        }

        pr_debug("svms %p [0x%lx 0x%lx] best restore 0x%x, actual loc 0x%x\n",
                 svms, prange->start, prange->last, best_loc,
                 prange->actual_loc);

        if (prange->actual_loc != best_loc) {
                if (best_loc) {
                        r = svm_migrate_to_vram(prange, best_loc, mm);
                        if (r) {
                                pr_debug("svm_migrate_to_vram failed (%d) at %llx, falling back to system memory\n",
                                         r, addr);
                                /* Fallback to system memory if migration to
                                 * VRAM failed
                                 */
                                if (prange->actual_loc)
                                        r = svm_migrate_vram_to_ram(prange, mm);
                                else
                                        r = 0;
                        }
                } else {
                        r = svm_migrate_vram_to_ram(prange, mm);
                }
                if (r) {
                        pr_debug("failed %d to migrate svms %p [0x%lx 0x%lx]\n",
                                 r, svms, prange->start, prange->last);
                        goto out_unlock_range;
                }
        }

        r = svm_range_validate_and_map(mm, prange, gpuidx, false, false);
        if (r)
                pr_debug("failed %d to map svms 0x%p [0x%lx 0x%lx] to gpus\n",
                         r, svms, prange->start, prange->last);

out_unlock_range:
        mutex_unlock(&prange->migrate_mutex);
out_unlock_svms:
        mutex_unlock(&svms->lock);
        mmap_read_unlock(mm);

        svm_range_count_fault(adev, p, gpuidx);

        mmput(mm);
out:
        kfd_unref_process(p);

        if (r == -EAGAIN) {
                pr_debug("recover vm fault later\n");
                amdgpu_gmc_filter_faults_remove(adev, addr, pasid);
                r = 0;
        }
        return r;
}

void svm_range_list_fini(struct kfd_process *p)
{
        struct svm_range *prange;
        struct svm_range *next;

        pr_debug("pasid 0x%x svms 0x%p\n", p->pasid, &p->svms);

        /* Ensure list work is finished before process is destroyed */
        flush_work(&p->svms.deferred_list_work);

        list_for_each_entry_safe(prange, next, &p->svms.list, list) {
                svm_range_unlink(prange);
                svm_range_remove_notifier(prange);
                svm_range_free(prange);
        }

        mutex_destroy(&p->svms.lock);

        pr_debug("pasid 0x%x svms 0x%p done\n", p->pasid, &p->svms);
}

int svm_range_list_init(struct kfd_process *p)
{
        struct svm_range_list *svms = &p->svms;
        int i;

        svms->objects = RB_ROOT_CACHED;
        mutex_init(&svms->lock);
        INIT_LIST_HEAD(&svms->list);
        atomic_set(&svms->evicted_ranges, 0);
        INIT_DELAYED_WORK(&svms->restore_work, svm_range_restore_work);
        INIT_WORK(&svms->deferred_list_work, svm_range_deferred_list_work);
        INIT_LIST_HEAD(&svms->deferred_range_list);
        spin_lock_init(&svms->deferred_list_lock);

        for (i = 0; i < p->n_pdds; i++)
                if (KFD_IS_SVM_API_SUPPORTED(p->pdds[i]->dev))
                        bitmap_set(svms->bitmap_supported, i, 1);

        return 0;
}

/**
 * svm_range_is_valid - check if virtual address range is valid
 * @mm: current process mm_struct
 * @start: range start address, in pages
 * @size: range size, in pages
 *
 * Valid virtual address range means it belongs to one or more VMAs
 *
 * Context: Process context
 *
 * Return:
 *  true - valid svm range
 *  false - invalid svm range
 */
static bool
svm_range_is_valid(struct mm_struct *mm, uint64_t start, uint64_t size)
{
        const unsigned long device_vma = VM_IO | VM_PFNMAP | VM_MIXEDMAP;
        struct vm_area_struct *vma;
        unsigned long end;

        start <<= PAGE_SHIFT;
        end = start + (size << PAGE_SHIFT);

        do {
                vma = find_vma(mm, start);
                if (!vma || start < vma->vm_start ||
                    (vma->vm_flags & device_vma))
                        return false;
                start = min(end, vma->vm_end);
        } while (start < end);

        return true;
}

/**
 * svm_range_add - add svm range and handle overlap
 * @p: the range add to this process svms
 * @start: page size aligned
 * @size: page size aligned
 * @nattr: number of attributes
 * @attrs: array of attributes
 * @update_list: output, the ranges need validate and update GPU mapping
 * @insert_list: output, the ranges need insert to svms
 * @remove_list: output, the ranges are replaced and need remove from svms
 *
 * Check if the virtual address range has overlap with the registered ranges,
 * split the overlapped range, copy and adjust pages address and vram nodes in
 * old and new ranges.
 *
 * Context: Process context, caller must hold svms->lock
 *
 * Return:
 * 0 - OK, otherwise error code
 */
static int
svm_range_add(struct kfd_process *p, uint64_t start, uint64_t size,
              uint32_t nattr, struct kfd_ioctl_svm_attribute *attrs,
              struct list_head *update_list, struct list_head *insert_list,
              struct list_head *remove_list)
{
        uint64_t last = start + size - 1UL;
        struct svm_range_list *svms;
        struct svm_range new = {0};
        struct svm_range *prange;
        unsigned long left = 0;
        int r = 0;

        pr_debug("svms 0x%p [0x%llx 0x%llx]\n", &p->svms, start, last);

        svm_range_apply_attrs(p, &new, nattr, attrs);

        svms = &p->svms;

        r = svm_range_handle_overlap(svms, &new, start, last, update_list,
                                     insert_list, remove_list, &left);
        if (r)
                return r;

        if (left) {
                prange = svm_range_new(svms, last - left + 1, last);
                list_add(&prange->insert_list, insert_list);
                list_add(&prange->update_list, update_list);
        }

        return 0;
}

/**
 * svm_range_best_prefetch_location - decide the best prefetch location
 * @prange: svm range structure
 *
 * For xnack off:
 * If range map to single GPU, the best prefetch location is prefetch_loc, which
 * can be CPU or GPU.
 *
 * If range is ACCESS or ACCESS_IN_PLACE by mGPUs, only if mGPU connection on
 * XGMI same hive, the best prefetch location is prefetch_loc GPU, othervise
 * the best prefetch location is always CPU, because GPU can not have coherent
 * mapping VRAM of other GPUs even with large-BAR PCIe connection.
 *
 * For xnack on:
 * If range is not ACCESS_IN_PLACE by mGPUs, the best prefetch location is
 * prefetch_loc, other GPU access will generate vm fault and trigger migration.
 *
 * If range is ACCESS_IN_PLACE by mGPUs, only if mGPU connection on XGMI same
 * hive, the best prefetch location is prefetch_loc GPU, otherwise the best
 * prefetch location is always CPU.
 *
 * Context: Process context
 *
 * Return:
 * 0 for CPU or GPU id
 */
static uint32_t
svm_range_best_prefetch_location(struct svm_range *prange)
{
        DECLARE_BITMAP(bitmap, MAX_GPU_INSTANCE);
        uint32_t best_loc = prange->prefetch_loc;
        struct kfd_process_device *pdd;
        struct amdgpu_device *bo_adev;
        struct amdgpu_device *adev;
        struct kfd_process *p;
        uint32_t gpuidx;

        p = container_of(prange->svms, struct kfd_process, svms);

        if (!best_loc || best_loc == KFD_IOCTL_SVM_LOCATION_UNDEFINED)
                goto out;

        bo_adev = svm_range_get_adev_by_id(prange, best_loc);
        if (!bo_adev) {
                WARN_ONCE(1, "failed to get device by id 0x%x\n", best_loc);
                best_loc = 0;
                goto out;
        }

        if (p->xnack_enabled)
                bitmap_copy(bitmap, prange->bitmap_aip, MAX_GPU_INSTANCE);
        else
                bitmap_or(bitmap, prange->bitmap_access, prange->bitmap_aip,
                          MAX_GPU_INSTANCE);

        for_each_set_bit(gpuidx, bitmap, MAX_GPU_INSTANCE) {
                pdd = kfd_process_device_from_gpuidx(p, gpuidx);
                if (!pdd) {
                        pr_debug("failed to get device by idx 0x%x\n", gpuidx);
                        continue;
                }
                adev = (struct amdgpu_device *)pdd->dev->kgd;

                if (adev == bo_adev)
                        continue;

                if (!amdgpu_xgmi_same_hive(adev, bo_adev)) {
                        best_loc = 0;
                        break;
                }
        }

out:
        pr_debug("xnack %d svms 0x%p [0x%lx 0x%lx] best loc 0x%x\n",
                 p->xnack_enabled, &p->svms, prange->start, prange->last,
                 best_loc);

        return best_loc;
}

/* FIXME: This is a workaround for page locking bug when some pages are
 * invalid during migration to VRAM
 */
void svm_range_prefault(struct svm_range *prange, struct mm_struct *mm,
                        void *owner)
{
        struct hmm_range *hmm_range;
        int r;

        if (prange->validated_once)
                return;

        r = amdgpu_hmm_range_get_pages(&prange->notifier, mm, NULL,
                                       prange->start << PAGE_SHIFT,
                                       prange->npages, &hmm_range,
                                       false, true, owner);
        if (!r) {
                amdgpu_hmm_range_get_pages_done(hmm_range);
                prange->validated_once = true;
        }
}

/* svm_range_trigger_migration - start page migration if prefetch loc changed
 * @mm: current process mm_struct
 * @prange: svm range structure
 * @migrated: output, true if migration is triggered
 *
 * If range perfetch_loc is GPU, actual loc is cpu 0, then migrate the range
 * from ram to vram.
 * If range prefetch_loc is cpu 0, actual loc is GPU, then migrate the range
 * from vram to ram.
 *
 * If GPU vm fault retry is not enabled, migration interact with MMU notifier
 * and restore work:
 * 1. migrate_vma_setup invalidate pages, MMU notifier callback svm_range_evict
 *    stops all queues, schedule restore work
 * 2. svm_range_restore_work wait for migration is done by
 *    a. svm_range_validate_vram takes prange->migrate_mutex
 *    b. svm_range_validate_ram HMM get pages wait for CPU fault handle returns
 * 3. restore work update mappings of GPU, resume all queues.
 *
 * Context: Process context
 *
 * Return:
 * 0 - OK, otherwise - error code of migration
 */
static int
svm_range_trigger_migration(struct mm_struct *mm, struct svm_range *prange,
                            bool *migrated)
{
        uint32_t best_loc;
        int r = 0;

        *migrated = false;
        best_loc = svm_range_best_prefetch_location(prange);

        if (best_loc == KFD_IOCTL_SVM_LOCATION_UNDEFINED ||
            best_loc == prange->actual_loc)
                return 0;

        if (!best_loc) {
                r = svm_migrate_vram_to_ram(prange, mm);
                *migrated = !r;
                return r;
        }

        r = svm_migrate_to_vram(prange, best_loc, mm);
        *migrated = !r;

        return r;
}

int svm_range_schedule_evict_svm_bo(struct amdgpu_amdkfd_fence *fence)
{
        if (!fence)
                return -EINVAL;

        if (dma_fence_is_signaled(&fence->base))
                return 0;

        if (fence->svm_bo) {
                WRITE_ONCE(fence->svm_bo->evicting, 1);
                schedule_work(&fence->svm_bo->eviction_work);
        }

        return 0;
}

static void svm_range_evict_svm_bo_worker(struct work_struct *work)
{
        struct svm_range_bo *svm_bo;
        struct kfd_process *p;
        struct mm_struct *mm;

        svm_bo = container_of(work, struct svm_range_bo, eviction_work);
        if (!svm_bo_ref_unless_zero(svm_bo))
                return; /* svm_bo was freed while eviction was pending */

        /* svm_range_bo_release destroys this worker thread. So during
         * the lifetime of this thread, kfd_process and mm will be valid.
         */
        p = container_of(svm_bo->svms, struct kfd_process, svms);
        mm = p->mm;
        if (!mm)
                return;

        mmap_read_lock(mm);
        spin_lock(&svm_bo->list_lock);
        while (!list_empty(&svm_bo->range_list)) {
                struct svm_range *prange =
                                list_first_entry(&svm_bo->range_list,
                                                struct svm_range, svm_bo_list);
                list_del_init(&prange->svm_bo_list);
                spin_unlock(&svm_bo->list_lock);

                pr_debug("svms 0x%p [0x%lx 0x%lx]\n", prange->svms,
                         prange->start, prange->last);

                mutex_lock(&prange->migrate_mutex);
                svm_migrate_vram_to_ram(prange, svm_bo->eviction_fence->mm);

                mutex_lock(&prange->lock);
                prange->svm_bo = NULL;
                mutex_unlock(&prange->lock);

                mutex_unlock(&prange->migrate_mutex);

                spin_lock(&svm_bo->list_lock);
        }
        spin_unlock(&svm_bo->list_lock);
        mmap_read_unlock(mm);

        dma_fence_signal(&svm_bo->eviction_fence->base);
        /* This is the last reference to svm_bo, after svm_range_vram_node_free
         * has been called in svm_migrate_vram_to_ram
         */
        WARN_ONCE(kref_read(&svm_bo->kref) != 1, "This was not the last reference\n");
        svm_range_bo_unref(svm_bo);
}

static int
svm_range_set_attr(struct kfd_process *p, uint64_t start, uint64_t size,
                   uint32_t nattr, struct kfd_ioctl_svm_attribute *attrs)
{
        struct amdkfd_process_info *process_info = p->kgd_process_info;
        struct mm_struct *mm = current->mm;
        struct list_head update_list;
        struct list_head insert_list;
        struct list_head remove_list;
        struct svm_range_list *svms;
        struct svm_range *prange;
        struct svm_range *next;
        int r = 0;

        pr_debug("pasid 0x%x svms 0x%p [0x%llx 0x%llx] pages 0x%llx\n",
                 p->pasid, &p->svms, start, start + size - 1, size);

        r = svm_range_check_attr(p, nattr, attrs);
        if (r)
                return r;

        svms = &p->svms;