From: Philip Yang <philip.y...@amd.com>

If svm range perfetch location is not zero, use TTM to alloc
amdgpu_bo vram nodes to validate svm range, then map vram nodes to GPUs.

Use offset to sub allocate from the same amdgpu_bo to handle overlap
vram range while adding new range or unmapping range.

svm_bo has ref count to trace the shared ranges. If all ranges of shared
amdgpu_bo are migrated to ram, ref count becomes 0, then amdgpu_bo is
released, all ranges svm_bo is set to NULL.

To migrate range from ram back to vram, allocate the same amdgpu_bo
with previous offset if the range has svm_bo.

Signed-off-by: Philip Yang <philip.y...@amd.com>
Signed-off-by: Alex Sierra <alex.sie...@amd.com>
Signed-off-by: Felix Kuehling <felix.kuehl...@amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 342 ++++++++++++++++++++++++---
 drivers/gpu/drm/amd/amdkfd/kfd_svm.h |  20 ++
 2 files changed, 335 insertions(+), 27 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c 
b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index e3ba6e7262a7..7d91dc49a5a9 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
@@ -35,7 +35,9 @@
  * svm_range_unlink - unlink svm_range from lists and interval tree
  * @prange: svm range structure to be removed
  *
- * Remove the svm range from svms interval tree and link list
+ * Remove the svm_range from the svms and svm_bo SRCU lists and the svms
+ * interval tree. After this call, synchronize_srcu is needed before the
+ * range can be freed safely.
  *
  * Context: The caller must hold svms_lock
  */
@@ -44,6 +46,12 @@ static void svm_range_unlink(struct svm_range *prange)
        pr_debug("prange 0x%p [0x%lx 0x%lx]\n", prange, prange->it_node.start,
                 prange->it_node.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_rcu(&prange->list);
        interval_tree_remove(&prange->it_node, &prange->svms->objects);
 }
@@ -70,6 +78,12 @@ static void svm_range_remove(struct svm_range *prange)
        pr_debug("svms 0x%p [0x%lx 0x%lx]\n", prange->svms,
                 prange->it_node.start, prange->it_node.last);
 
+       if (prange->mm_nodes) {
+               pr_debug("vram prange svms 0x%p [0x%lx 0x%lx]\n", prange->svms,
+                        prange->it_node.start, prange->it_node.last);
+               svm_range_vram_node_free(prange);
+       }
+
        kvfree(prange->pages_addr);
        kfree(prange);
 }
@@ -102,7 +116,9 @@ svm_range *svm_range_new(struct svm_range_list *svms, 
uint64_t start,
        INIT_LIST_HEAD(&prange->list);
        INIT_LIST_HEAD(&prange->update_list);
        INIT_LIST_HEAD(&prange->remove_list);
+       INIT_LIST_HEAD(&prange->svm_bo_list);
        atomic_set(&prange->invalid, 0);
+       spin_lock_init(&prange->svm_bo_lock);
        svm_range_set_default_attributes(&prange->preferred_loc,
                                         &prange->prefetch_loc,
                                         &prange->granularity, &prange->flags);
@@ -139,6 +155,16 @@ svm_get_supported_dev_by_id(struct kfd_process *p, 
uint32_t gpu_id,
        return dev;
 }
 
+struct amdgpu_device *
+svm_range_get_adev_by_id(struct svm_range *prange, uint32_t gpu_id)
+{
+       struct kfd_process *p =
+                       container_of(prange->svms, struct kfd_process, svms);
+       struct kfd_dev *dev = svm_get_supported_dev_by_id(p, gpu_id, NULL);
+
+       return dev ? (struct amdgpu_device *)dev->kgd : NULL;
+}
+
 /**
  * svm_range_validate_ram - get system memory pages of svm range
  *
@@ -186,14 +212,226 @@ svm_range_validate_ram(struct mm_struct *mm, struct 
svm_range *prange)
        return 0;
 }
 
+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 struct svm_range_bo *svm_range_bo_ref(struct svm_range_bo *svm_bo)
+{
+       if (svm_bo)
+               kref_get(&svm_bo->kref);
+
+       return svm_bo;
+}
+
+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);
+       /* This cleanup loop does not need to be SRCU safe because there
+        * should be no SRCU readers while the ref count is 0. Any SRCU
+        * reader that has a chance of reducing the ref count must take
+        * an extra reference before srcu_read_lock and release it after
+        * srcu_read_unlock.
+        */
+       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);
+               pr_debug("svms 0x%p [0x%lx 0x%lx]\n", prange->svms,
+                        prange->it_node.start, prange->it_node.last);
+               spin_lock(&prange->svm_bo_lock);
+               prange->svm_bo = NULL;
+               spin_unlock(&prange->svm_bo_lock);
+
+               /* 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);
+
+       amdgpu_bo_unref(&svm_bo->bo);
+       kfree(svm_bo);
+}
+
+static 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 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 amdkfd_process_info *process_info;
+       struct amdgpu_bo_param bp;
+       struct svm_range_bo *svm_bo;
+       struct amdgpu_bo *bo;
+       struct kfd_process *p;
+       int r;
+
+       pr_debug("[0x%lx 0x%lx]\n", prange->it_node.start,
+                prange->it_node.last);
+       spin_lock(&prange->svm_bo_lock);
+       if (prange->svm_bo) {
+               if (prange->mm_nodes) {
+                       /* We still have a reference, all is well */
+                       spin_unlock(&prange->svm_bo_lock);
+                       return 0;
+               }
+               if (svm_bo_ref_unless_zero(prange->svm_bo)) {
+                       /* The BO was still around and we got
+                        * a new reference to it
+                        */
+                       spin_unlock(&prange->svm_bo_lock);
+                       pr_debug("reuse old bo [0x%lx 0x%lx]\n",
+                               prange->it_node.start, prange->it_node.last);
+
+                       prange->mm_nodes = prange->svm_bo->bo->tbo.mem.mm_node;
+                       return 0;
+               }
+
+               spin_unlock(&prange->svm_bo_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))
+                       ;
+
+       } else {
+               spin_unlock(&prange->svm_bo_lock);
+       }
+
+       svm_bo = svm_range_bo_new();
+       if (!svm_bo) {
+               pr_debug("failed to alloc svm bo\n");
+               return -ENOMEM;
+       }
+
+       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.type = ttm_bo_type_device;
+       bp.resv = NULL;
+
+       r = amdgpu_bo_create(adev, &bp, &bo);
+       if (r) {
+               pr_debug("failed %d to create bo\n", r);
+               kfree(svm_bo);
+               return r;
+       }
+
+       p = container_of(prange->svms, struct kfd_process, svms);
+       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;
+       }
+       process_info = p->kgd_process_info;
+       amdgpu_bo_fence(bo, &process_info->eviction_fence->base, true);
+
+       amdgpu_bo_unreserve(bo);
+
+       svm_bo->bo = bo;
+       prange->svm_bo = svm_bo;
+       prange->mm_nodes = bo->tbo.mem.mm_node;
+       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:
+       kfree(svm_bo);
+       amdgpu_bo_unref(&bo);
+       prange->mm_nodes = NULL;
+
+       return r;
+}
+
+void svm_range_vram_node_free(struct svm_range *prange)
+{
+       pr_debug("svms 0x%p [0x%lx 0x%lx]\n", prange->svms,
+                prange->it_node.start, prange->it_node.last);
+
+       svm_range_bo_unref(prange->svm_bo);
+       prange->mm_nodes = NULL;
+}
+
+static int svm_range_validate_vram(struct svm_range *prange)
+{
+       struct amdgpu_device *adev;
+       int r;
+
+       pr_debug("svms 0x%p [0x%lx 0x%lx] actual_loc 0x%x\n", prange->svms,
+                prange->it_node.start, prange->it_node.last,
+                prange->actual_loc);
+
+       adev = svm_range_get_adev_by_id(prange, prange->actual_loc);
+       if (!adev) {
+               pr_debug("failed to get device by id 0x%x\n",
+                        prange->actual_loc);
+               return -EINVAL;
+       }
+
+       r = svm_range_vram_node_new(adev, prange, true);
+       if (r)
+               pr_debug("failed %d to alloc vram\n", r);
+
+       return r;
+}
+
 static int
 svm_range_validate(struct mm_struct *mm, struct svm_range *prange)
 {
-       int r = 0;
+       int r;
 
        pr_debug("actual loc 0x%x\n", prange->actual_loc);
 
-       r = svm_range_validate_ram(mm, prange);
+       if (!prange->actual_loc)
+               r = svm_range_validate_ram(mm, prange);
+       else
+               r = svm_range_validate_vram(prange);
 
        pr_debug("svms 0x%p [0x%lx 0x%lx] ret %d invalid %d\n", prange->svms,
                 prange->it_node.start, prange->it_node.last,
@@ -349,6 +587,35 @@ svm_range_split_pages(struct svm_range *new, struct 
svm_range *old,
        return 0;
 }
 
+static int
+svm_range_split_nodes(struct svm_range *new, struct svm_range *old,
+                     uint64_t start, uint64_t last)
+{
+       pr_debug("svms 0x%p new start 0x%lx start 0x%llx last 0x%llx\n",
+                new->svms, new->it_node.start, start, last);
+
+       old->npages = last - start + 1;
+
+       if (new->it_node.start == old->it_node.start) {
+               new->offset = old->offset;
+               old->offset += new->npages;
+       } else {
+               new->offset = old->offset + old->npages;
+       }
+
+       old->it_node.start = start;
+       old->it_node.last = last;
+
+       new->svm_bo = svm_range_bo_ref(old->svm_bo);
+       new->mm_nodes = old->mm_nodes;
+
+       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
  *
@@ -382,6 +649,8 @@ svm_range_split_adjust(struct svm_range *new, struct 
svm_range *old,
 
        if (old->pages_addr)
                r = svm_range_split_pages(new, old, start, last);
+       else if (old->actual_loc && old->mm_nodes)
+               r = svm_range_split_nodes(new, old, start, last);
        else
                WARN_ONCE(1, "split adjust invalid pages_addr and nodes\n");
        if (r)
@@ -438,17 +707,14 @@ svm_range_split(struct svm_range *prange, uint64_t start, 
uint64_t last,
                return -EINVAL;
 
        svms = prange->svms;
-       if (old_start == start) {
+       if (old_start == start)
                *new = svm_range_new(svms, last + 1, old_last);
-               if (!*new)
-                       return -ENOMEM;
-               r = svm_range_split_adjust(*new, prange, start, last);
-       } else {
+       else
                *new = svm_range_new(svms, old_start, start - 1);
-               if (!*new)
-                       return -ENOMEM;
-               r = svm_range_split_adjust(*new, prange, start, last);
-       }
+       if (!*new)
+               return -ENOMEM;
+
+       r = svm_range_split_adjust(*new, prange, start, last);
 
        return r;
 }
@@ -550,7 +816,8 @@ svm_range_get_pte_flags(struct amdgpu_device *adev, struct 
svm_range *prange)
        uint64_t pte_flags;
 
        pte_flags = AMDGPU_PTE_VALID;
-       pte_flags |= AMDGPU_PTE_SYSTEM | AMDGPU_PTE_SNOOPED;
+       if (!prange->mm_nodes)
+               pte_flags |= AMDGPU_PTE_SYSTEM | AMDGPU_PTE_SNOOPED;
 
        mapping_flags = AMDGPU_VM_PAGE_READABLE | AMDGPU_VM_PAGE_WRITEABLE;
 
@@ -570,7 +837,9 @@ svm_range_get_pte_flags(struct amdgpu_device *adev, struct 
svm_range *prange)
        /* Apply ASIC specific mapping flags */
        amdgpu_gmc_get_vm_pte(adev, &prange->mapping, &pte_flags);
 
-       pr_debug("PTE flags 0x%llx\n", pte_flags);
+       pr_debug("svms 0x%p [0x%lx 0x%lx] vram %d system %d PTE flags 0x%llx\n",
+                prange->svms, prange->it_node.start, prange->it_node.last,
+                prange->mm_nodes ? 1:0, prange->pages_addr ? 1:0, pte_flags);
 
        return pte_flags;
 }
@@ -656,7 +925,9 @@ svm_range_map_to_gpu(struct amdgpu_device *adev, struct 
amdgpu_vm *vm,
                     struct svm_range *prange, bool reserve_vm,
                     struct dma_fence **fence)
 {
-       struct amdgpu_bo *root;
+       struct ttm_validate_buffer tv[2];
+       struct ww_acquire_ctx ticket;
+       struct list_head list;
        dma_addr_t *pages_addr;
        uint64_t pte_flags;
        int r = 0;
@@ -665,13 +936,25 @@ svm_range_map_to_gpu(struct amdgpu_device *adev, struct 
amdgpu_vm *vm,
                 prange->it_node.start, prange->it_node.last);
 
        if (reserve_vm) {
-               root = amdgpu_bo_ref(vm->root.base.bo);
-               r = amdgpu_bo_reserve(root, true);
+               INIT_LIST_HEAD(&list);
+
+               tv[0].bo = &vm->root.base.bo->tbo;
+               tv[0].num_shared = 4;
+               list_add(&tv[0].head, &list);
+               if (prange->svm_bo && prange->mm_nodes) {
+                       tv[1].bo = &prange->svm_bo->bo->tbo;
+                       tv[1].num_shared = 1;
+                       list_add(&tv[1].head, &list);
+               }
+               r = ttm_eu_reserve_buffers(&ticket, &list, true, NULL);
                if (r) {
-                       pr_debug("failed %d to reserve root bo\n", r);
-                       amdgpu_bo_unref(&root);
+                       pr_debug("failed %d to reserve bo\n", r);
                        goto out;
                }
+               if (prange->svm_bo && prange->mm_nodes &&
+                   prange->svm_bo->bo->tbo.evicted)
+                       goto unreserve_out;
+
                r = amdgpu_vm_validate_pt_bos(adev, vm, svm_range_bo_validate,
                                              NULL);
                if (r) {
@@ -682,7 +965,7 @@ svm_range_map_to_gpu(struct amdgpu_device *adev, struct 
amdgpu_vm *vm,
 
        prange->mapping.start = prange->it_node.start;
        prange->mapping.last = prange->it_node.last;
-       prange->mapping.offset = 0;
+       prange->mapping.offset = prange->offset;
        pte_flags = svm_range_get_pte_flags(adev, prange);
        prange->mapping.flags = pte_flags;
        pages_addr = prange->pages_addr;
@@ -690,7 +973,8 @@ svm_range_map_to_gpu(struct amdgpu_device *adev, struct 
amdgpu_vm *vm,
        r = amdgpu_vm_bo_update_mapping(adev, adev, vm, false, false, NULL,
                                        prange->mapping.start,
                                        prange->mapping.last, pte_flags,
-                                       prange->mapping.offset, NULL,
+                                       prange->mapping.offset,
+                                       prange->mm_nodes,
                                        pages_addr, &vm->last_update);
        if (r) {
                pr_debug("failed %d to map to gpu 0x%lx\n", r,
@@ -710,11 +994,8 @@ svm_range_map_to_gpu(struct amdgpu_device *adev, struct 
amdgpu_vm *vm,
                *fence = dma_fence_get(vm->last_update);
 
 unreserve_out:
-       if (reserve_vm) {
-               amdgpu_bo_unreserve(root);
-               amdgpu_bo_unref(&root);
-       }
-
+       if (reserve_vm)
+               ttm_eu_backoff_reservation(&ticket, &list);
 out:
        return r;
 }
@@ -929,7 +1210,14 @@ struct svm_range *svm_range_clone(struct svm_range *old)
                memcpy(new->pages_addr, old->pages_addr,
                       old->npages * sizeof(*old->pages_addr));
        }
-
+       if (old->svm_bo) {
+               new->mm_nodes = old->mm_nodes;
+               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;
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.h 
b/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
index 4c7daf8e0b6f..b1d2db02043b 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_svm.h
@@ -32,6 +32,12 @@
 #include "amdgpu.h"
 #include "kfd_priv.h"
 
+struct svm_range_bo {
+       struct amdgpu_bo        *bo;
+       struct kref             kref;
+       struct list_head        range_list; /* all svm ranges shared this bo */
+       spinlock_t              list_lock;
+};
 /**
  * struct svm_range - shared virtual memory range
  *
@@ -45,6 +51,10 @@
  * @mapping:    bo_va mapping structure to create and update GPU page table
  * @npages:     number of pages
  * @pages_addr: list of system memory physical page address
+ * @mm_nodes:   vram nodes allocated
+ * @offset:     range start offset within mm_nodes
+ * @svm_bo:     struct to manage splited amdgpu_bo
+ * @svm_bo_list:link list node, to scan all ranges which share same svm_bo
  * @flags:      flags defined as KFD_IOCTL_SVM_FLAG_*
  * @perferred_loc: perferred location, 0 for CPU, or GPU id
  * @perfetch_loc: last prefetch location, 0 for CPU, or GPU id
@@ -68,6 +78,11 @@ struct svm_range {
        struct amdgpu_bo_va_mapping     mapping;
        uint64_t                        npages;
        dma_addr_t                      *pages_addr;
+       struct drm_mm_node              *mm_nodes;
+       uint64_t                        offset;
+       struct svm_range_bo             *svm_bo;
+       struct list_head                svm_bo_list;
+       spinlock_t                      svm_bo_lock;
        uint32_t                        flags;
        uint32_t                        preferred_loc;
        uint32_t                        prefetch_loc;
@@ -95,5 +110,10 @@ void svm_range_list_fini(struct kfd_process *p);
 int svm_ioctl(struct kfd_process *p, enum kfd_ioctl_svm_op op, uint64_t start,
              uint64_t size, uint32_t nattrs,
              struct kfd_ioctl_svm_attribute *attrs);
+struct amdgpu_device *svm_range_get_adev_by_id(struct svm_range *prange,
+                                              uint32_t id);
+int svm_range_vram_node_new(struct amdgpu_device *adev,
+                           struct svm_range *prange, bool clear);
+void svm_range_vram_node_free(struct svm_range *prange);
 
 #endif /* KFD_SVM_H_ */
-- 
2.29.2

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