Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1055 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
new file mode 100644
index 000000000..659313648
--- /dev/null
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_migrate.c
@@ -0,0 +1,1055 @@
+// 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/hmm.h>
+#include <linux/dma-direction.h>
+#include <linux/dma-mapping.h>
+#include <linux/migrate.h>
+#include "amdgpu_sync.h"
+#include "amdgpu_object.h"
+#include "amdgpu_vm.h"
+#include "amdgpu_res_cursor.h"
+#include "kfd_priv.h"
+#include "kfd_svm.h"
+#include "kfd_migrate.h"
+#include "kfd_smi_events.h"
+
+#ifdef dev_fmt
+#undef dev_fmt
+#endif
+#define dev_fmt(fmt) "kfd_migrate: " fmt
+
+static uint64_t
+svm_migrate_direct_mapping_addr(struct amdgpu_device *adev, uint64_t addr)
+{
+	return addr + amdgpu_ttm_domain_start(adev, TTM_PL_VRAM);
+}
+
+static int
+svm_migrate_gart_map(struct amdgpu_ring *ring, uint64_t npages,
+		     dma_addr_t *addr, uint64_t *gart_addr, uint64_t flags)
+{
+	struct amdgpu_device *adev = ring->adev;
+	struct amdgpu_job *job;
+	unsigned int num_dw, num_bytes;
+	struct dma_fence *fence;
+	uint64_t src_addr, dst_addr;
+	uint64_t pte_flags;
+	void *cpu_addr;
+	int r;
+
+	/* use gart window 0 */
+	*gart_addr = adev->gmc.gart_start;
+
+	num_dw = ALIGN(adev->mman.buffer_funcs->copy_num_dw, 8);
+	num_bytes = npages * 8;
+
+	r = amdgpu_job_alloc_with_ib(adev, &adev->mman.high_pr,
+				     AMDGPU_FENCE_OWNER_UNDEFINED,
+				     num_dw * 4 + num_bytes,
+				     AMDGPU_IB_POOL_DELAYED,
+				     &job);
+	if (r)
+		return r;
+
+	src_addr = num_dw * 4;
+	src_addr += job->ibs[0].gpu_addr;
+
+	dst_addr = amdgpu_bo_gpu_offset(adev->gart.bo);
+	amdgpu_emit_copy_buffer(adev, &job->ibs[0], src_addr,
+				dst_addr, num_bytes, false);
+
+	amdgpu_ring_pad_ib(ring, &job->ibs[0]);
+	WARN_ON(job->ibs[0].length_dw > num_dw);
+
+	pte_flags = AMDGPU_PTE_VALID | AMDGPU_PTE_READABLE;
+	pte_flags |= AMDGPU_PTE_SYSTEM | AMDGPU_PTE_SNOOPED;
+	if (!(flags & KFD_IOCTL_SVM_FLAG_GPU_RO))
+		pte_flags |= AMDGPU_PTE_WRITEABLE;
+	pte_flags |= adev->gart.gart_pte_flags;
+
+	cpu_addr = &job->ibs[0].ptr[num_dw];
+
+	amdgpu_gart_map(adev, 0, npages, addr, pte_flags, cpu_addr);
+	fence = amdgpu_job_submit(job);
+	dma_fence_put(fence);
+
+	return r;
+}
+
+/**
+ * svm_migrate_copy_memory_gart - sdma copy data between ram and vram
+ *
+ * @adev: amdgpu device the sdma ring running
+ * @sys: system DMA pointer to be copied
+ * @vram: vram destination DMA pointer
+ * @npages: number of pages to copy
+ * @direction: enum MIGRATION_COPY_DIR
+ * @mfence: output, sdma fence to signal after sdma is done
+ *
+ * ram address uses GART table continuous entries mapping to ram pages,
+ * vram address uses direct mapping of vram pages, which must have npages
+ * number of continuous pages.
+ * GART update and sdma uses same buf copy function ring, sdma is splited to
+ * multiple GTT_MAX_PAGES transfer, all sdma operations are serialized, wait for
+ * the last sdma finish fence which is returned to check copy memory is done.
+ *
+ * Context: Process context, takes and releases gtt_window_lock
+ *
+ * Return:
+ * 0 - OK, otherwise error code
+ */
+
+static int
+svm_migrate_copy_memory_gart(struct amdgpu_device *adev, dma_addr_t *sys,
+			     uint64_t *vram, uint64_t npages,
+			     enum MIGRATION_COPY_DIR direction,
+			     struct dma_fence **mfence)
+{
+	const uint64_t GTT_MAX_PAGES = AMDGPU_GTT_MAX_TRANSFER_SIZE;
+	struct amdgpu_ring *ring = adev->mman.buffer_funcs_ring;
+	uint64_t gart_s, gart_d;
+	struct dma_fence *next;
+	uint64_t size;
+	int r;
+
+	mutex_lock(&adev->mman.gtt_window_lock);
+
+	while (npages) {
+		size = min(GTT_MAX_PAGES, npages);
+
+		if (direction == FROM_VRAM_TO_RAM) {
+			gart_s = svm_migrate_direct_mapping_addr(adev, *vram);
+			r = svm_migrate_gart_map(ring, size, sys, &gart_d, 0);
+
+		} else if (direction == FROM_RAM_TO_VRAM) {
+			r = svm_migrate_gart_map(ring, size, sys, &gart_s,
+						 KFD_IOCTL_SVM_FLAG_GPU_RO);
+			gart_d = svm_migrate_direct_mapping_addr(adev, *vram);
+		}
+		if (r) {
+			dev_err(adev->dev, "fail %d create gart mapping\n", r);
+			goto out_unlock;
+		}
+
+		r = amdgpu_copy_buffer(ring, gart_s, gart_d, size * PAGE_SIZE,
+				       NULL, &next, false, true, false);
+		if (r) {
+			dev_err(adev->dev, "fail %d to copy memory\n", r);
+			goto out_unlock;
+		}
+
+		dma_fence_put(*mfence);
+		*mfence = next;
+		npages -= size;
+		if (npages) {
+			sys += size;
+			vram += size;
+		}
+	}
+
+out_unlock:
+	mutex_unlock(&adev->mman.gtt_window_lock);
+
+	return r;
+}
+
+/**
+ * svm_migrate_copy_done - wait for memory copy sdma is done
+ *
+ * @adev: amdgpu device the sdma memory copy is executing on
+ * @mfence: migrate fence
+ *
+ * Wait for dma fence is signaled, if the copy ssplit into multiple sdma
+ * operations, this is the last sdma operation fence.
+ *
+ * Context: called after svm_migrate_copy_memory
+ *
+ * Return:
+ * 0		- success
+ * otherwise	- error code from dma fence signal
+ */
+static int
+svm_migrate_copy_done(struct amdgpu_device *adev, struct dma_fence *mfence)
+{
+	int r = 0;
+
+	if (mfence) {
+		r = dma_fence_wait(mfence, false);
+		dma_fence_put(mfence);
+		pr_debug("sdma copy memory fence done\n");
+	}
+
+	return r;
+}
+
+unsigned long
+svm_migrate_addr_to_pfn(struct amdgpu_device *adev, unsigned long addr)
+{
+	return (addr + adev->kfd.pgmap.range.start) >> PAGE_SHIFT;
+}
+
+static void
+svm_migrate_get_vram_page(struct svm_range *prange, unsigned long pfn)
+{
+	struct page *page;
+
+	page = pfn_to_page(pfn);
+	svm_range_bo_ref(prange->svm_bo);
+	page->zone_device_data = prange->svm_bo;
+	zone_device_page_init(page);
+}
+
+static void
+svm_migrate_put_vram_page(struct amdgpu_device *adev, unsigned long addr)
+{
+	struct page *page;
+
+	page = pfn_to_page(svm_migrate_addr_to_pfn(adev, addr));
+	unlock_page(page);
+	put_page(page);
+}
+
+static unsigned long
+svm_migrate_addr(struct amdgpu_device *adev, struct page *page)
+{
+	unsigned long addr;
+
+	addr = page_to_pfn(page) << PAGE_SHIFT;
+	return (addr - adev->kfd.pgmap.range.start);
+}
+
+static struct page *
+svm_migrate_get_sys_page(struct vm_area_struct *vma, unsigned long addr)
+{
+	struct page *page;
+
+	page = alloc_page_vma(GFP_HIGHUSER, vma, addr);
+	if (page)
+		lock_page(page);
+
+	return page;
+}
+
+static void svm_migrate_put_sys_page(unsigned long addr)
+{
+	struct page *page;
+
+	page = pfn_to_page(addr >> PAGE_SHIFT);
+	unlock_page(page);
+	put_page(page);
+}
+
+static unsigned long svm_migrate_successful_pages(struct migrate_vma *migrate)
+{
+	unsigned long cpages = 0;
+	unsigned long i;
+
+	for (i = 0; i < migrate->npages; i++) {
+		if (migrate->src[i] & MIGRATE_PFN_VALID &&
+		    migrate->src[i] & MIGRATE_PFN_MIGRATE)
+			cpages++;
+	}
+	return cpages;
+}
+
+static unsigned long svm_migrate_unsuccessful_pages(struct migrate_vma *migrate)
+{
+	unsigned long upages = 0;
+	unsigned long i;
+
+	for (i = 0; i < migrate->npages; i++) {
+		if (migrate->src[i] & MIGRATE_PFN_VALID &&
+		    !(migrate->src[i] & MIGRATE_PFN_MIGRATE))
+			upages++;
+	}
+	return upages;
+}
+
+static int
+svm_migrate_copy_to_vram(struct kfd_node *node, struct svm_range *prange,
+			 struct migrate_vma *migrate, struct dma_fence **mfence,
+			 dma_addr_t *scratch, uint64_t ttm_res_offset)
+{
+	uint64_t npages = migrate->cpages;
+	struct amdgpu_device *adev = node->adev;
+	struct device *dev = adev->dev;
+	struct amdgpu_res_cursor cursor;
+	dma_addr_t *src;
+	uint64_t *dst;
+	uint64_t i, j;
+	int r;
+
+	pr_debug("svms 0x%p [0x%lx 0x%lx 0x%llx]\n", prange->svms, prange->start,
+		 prange->last, ttm_res_offset);
+
+	src = scratch;
+	dst = (uint64_t *)(scratch + npages);
+
+	amdgpu_res_first(prange->ttm_res, ttm_res_offset,
+			 npages << PAGE_SHIFT, &cursor);
+	for (i = j = 0; i < npages; i++) {
+		struct page *spage;
+
+		dst[i] = cursor.start + (j << PAGE_SHIFT);
+		migrate->dst[i] = svm_migrate_addr_to_pfn(adev, dst[i]);
+		svm_migrate_get_vram_page(prange, migrate->dst[i]);
+		migrate->dst[i] = migrate_pfn(migrate->dst[i]);
+
+		spage = migrate_pfn_to_page(migrate->src[i]);
+		if (spage && !is_zone_device_page(spage)) {
+			src[i] = dma_map_page(dev, spage, 0, PAGE_SIZE,
+					      DMA_TO_DEVICE);
+			r = dma_mapping_error(dev, src[i]);
+			if (r) {
+				dev_err(dev, "%s: fail %d dma_map_page\n",
+					__func__, r);
+				goto out_free_vram_pages;
+			}
+		} else {
+			if (j) {
+				r = svm_migrate_copy_memory_gart(
+						adev, src + i - j,
+						dst + i - j, j,
+						FROM_RAM_TO_VRAM,
+						mfence);
+				if (r)
+					goto out_free_vram_pages;
+				amdgpu_res_next(&cursor, (j + 1) << PAGE_SHIFT);
+				j = 0;
+			} else {
+				amdgpu_res_next(&cursor, PAGE_SIZE);
+			}
+			continue;
+		}
+
+		pr_debug_ratelimited("dma mapping src to 0x%llx, pfn 0x%lx\n",
+				     src[i] >> PAGE_SHIFT, page_to_pfn(spage));
+
+		if (j >= (cursor.size >> PAGE_SHIFT) - 1 && i < npages - 1) {
+			r = svm_migrate_copy_memory_gart(adev, src + i - j,
+							 dst + i - j, j + 1,
+							 FROM_RAM_TO_VRAM,
+							 mfence);
+			if (r)
+				goto out_free_vram_pages;
+			amdgpu_res_next(&cursor, (j + 1) * PAGE_SIZE);
+			j = 0;
+		} else {
+			j++;
+		}
+	}
+
+	r = svm_migrate_copy_memory_gart(adev, src + i - j, dst + i - j, j,
+					 FROM_RAM_TO_VRAM, mfence);
+
+out_free_vram_pages:
+	if (r) {
+		pr_debug("failed %d to copy memory to vram\n", r);
+		while (i--) {
+			svm_migrate_put_vram_page(adev, dst[i]);
+			migrate->dst[i] = 0;
+		}
+	}
+
+#ifdef DEBUG_FORCE_MIXED_DOMAINS
+	for (i = 0, j = 0; i < npages; i += 4, j++) {
+		if (j & 1)
+			continue;
+		svm_migrate_put_vram_page(adev, dst[i]);
+		migrate->dst[i] = 0;
+		svm_migrate_put_vram_page(adev, dst[i + 1]);
+		migrate->dst[i + 1] = 0;
+		svm_migrate_put_vram_page(adev, dst[i + 2]);
+		migrate->dst[i + 2] = 0;
+		svm_migrate_put_vram_page(adev, dst[i + 3]);
+		migrate->dst[i + 3] = 0;
+	}
+#endif
+
+	return r;
+}
+
+static long
+svm_migrate_vma_to_vram(struct kfd_node *node, struct svm_range *prange,
+			struct vm_area_struct *vma, uint64_t start,
+			uint64_t end, uint32_t trigger, uint64_t ttm_res_offset)
+{
+	struct kfd_process *p = container_of(prange->svms, struct kfd_process, svms);
+	uint64_t npages = (end - start) >> PAGE_SHIFT;
+	struct amdgpu_device *adev = node->adev;
+	struct kfd_process_device *pdd;
+	struct dma_fence *mfence = NULL;
+	struct migrate_vma migrate = { 0 };
+	unsigned long cpages = 0;
+	dma_addr_t *scratch;
+	void *buf;
+	int r = -ENOMEM;
+
+	memset(&migrate, 0, sizeof(migrate));
+	migrate.vma = vma;
+	migrate.start = start;
+	migrate.end = end;
+	migrate.flags = MIGRATE_VMA_SELECT_SYSTEM;
+	migrate.pgmap_owner = SVM_ADEV_PGMAP_OWNER(adev);
+
+	buf = kvcalloc(npages,
+		       2 * sizeof(*migrate.src) + sizeof(uint64_t) + sizeof(dma_addr_t),
+		       GFP_KERNEL);
+	if (!buf)
+		goto out;
+
+	migrate.src = buf;
+	migrate.dst = migrate.src + npages;
+	scratch = (dma_addr_t *)(migrate.dst + npages);
+
+	kfd_smi_event_migration_start(node, p->lead_thread->pid,
+				      start >> PAGE_SHIFT, end >> PAGE_SHIFT,
+				      0, node->id, prange->prefetch_loc,
+				      prange->preferred_loc, trigger);
+
+	r = migrate_vma_setup(&migrate);
+	if (r) {
+		dev_err(adev->dev, "%s: vma setup fail %d range [0x%lx 0x%lx]\n",
+			__func__, r, prange->start, prange->last);
+		goto out_free;
+	}
+
+	cpages = migrate.cpages;
+	if (!cpages) {
+		pr_debug("failed collect migrate sys pages [0x%lx 0x%lx]\n",
+			 prange->start, prange->last);
+		goto out_free;
+	}
+	if (cpages != npages)
+		pr_debug("partial migration, 0x%lx/0x%llx pages migrated\n",
+			 cpages, npages);
+	else
+		pr_debug("0x%lx pages migrated\n", cpages);
+
+	r = svm_migrate_copy_to_vram(node, prange, &migrate, &mfence, scratch, ttm_res_offset);
+	migrate_vma_pages(&migrate);
+
+	pr_debug("successful/cpages/npages 0x%lx/0x%lx/0x%lx\n",
+		svm_migrate_successful_pages(&migrate), cpages, migrate.npages);
+
+	svm_migrate_copy_done(adev, mfence);
+	migrate_vma_finalize(&migrate);
+
+	kfd_smi_event_migration_end(node, p->lead_thread->pid,
+				    start >> PAGE_SHIFT, end >> PAGE_SHIFT,
+				    0, node->id, trigger);
+
+	svm_range_dma_unmap(adev->dev, scratch, 0, npages);
+
+out_free:
+	kvfree(buf);
+out:
+	if (!r && cpages) {
+		pdd = svm_range_get_pdd_by_node(prange, node);
+		if (pdd)
+			WRITE_ONCE(pdd->page_in, pdd->page_in + cpages);
+
+		return cpages;
+	}
+	return r;
+}
+
+/**
+ * svm_migrate_ram_to_vram - migrate svm range from system to device
+ * @prange: range structure
+ * @best_loc: the device to migrate to
+ * @mm: the process mm structure
+ * @trigger: reason of migration
+ *
+ * Context: Process context, caller hold mmap read lock, svms lock, prange lock
+ *
+ * Return:
+ * 0 - OK, otherwise error code
+ */
+static int
+svm_migrate_ram_to_vram(struct svm_range *prange, uint32_t best_loc,
+			struct mm_struct *mm, uint32_t trigger)
+{
+	unsigned long addr, start, end;
+	struct vm_area_struct *vma;
+	uint64_t ttm_res_offset;
+	struct kfd_node *node;
+	unsigned long cpages = 0;
+	long r = 0;
+
+	if (prange->actual_loc == best_loc) {
+		pr_debug("svms 0x%p [0x%lx 0x%lx] already on best_loc 0x%x\n",
+			 prange->svms, prange->start, prange->last, best_loc);
+		return 0;
+	}
+
+	node = svm_range_get_node_by_id(prange, best_loc);
+	if (!node) {
+		pr_debug("failed to get kfd node by id 0x%x\n", best_loc);
+		return -ENODEV;
+	}
+
+	pr_debug("svms 0x%p [0x%lx 0x%lx] to gpu 0x%x\n", prange->svms,
+		 prange->start, prange->last, best_loc);
+
+	start = prange->start << PAGE_SHIFT;
+	end = (prange->last + 1) << PAGE_SHIFT;
+
+	r = svm_range_vram_node_new(node, prange, true);
+	if (r) {
+		dev_dbg(node->adev->dev, "fail %ld to alloc vram\n", r);
+		return r;
+	}
+	ttm_res_offset = prange->offset << PAGE_SHIFT;
+
+	for (addr = start; addr < end;) {
+		unsigned long next;
+
+		vma = vma_lookup(mm, addr);
+		if (!vma)
+			break;
+
+		next = min(vma->vm_end, end);
+		r = svm_migrate_vma_to_vram(node, prange, vma, addr, next, trigger, ttm_res_offset);
+		if (r < 0) {
+			pr_debug("failed %ld to migrate\n", r);
+			break;
+		} else {
+			cpages += r;
+		}
+		ttm_res_offset += next - addr;
+		addr = next;
+	}
+
+	if (cpages) {
+		prange->actual_loc = best_loc;
+		svm_range_free_dma_mappings(prange, true);
+	} else {
+		svm_range_vram_node_free(prange);
+	}
+
+	return r < 0 ? r : 0;
+}
+
+static void svm_migrate_page_free(struct page *page)
+{
+	struct svm_range_bo *svm_bo = page->zone_device_data;
+
+	if (svm_bo) {
+		pr_debug_ratelimited("ref: %d\n", kref_read(&svm_bo->kref));
+		svm_range_bo_unref_async(svm_bo);
+	}
+}
+
+static int
+svm_migrate_copy_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
+			struct migrate_vma *migrate, struct dma_fence **mfence,
+			dma_addr_t *scratch, uint64_t npages)
+{
+	struct device *dev = adev->dev;
+	uint64_t *src;
+	dma_addr_t *dst;
+	struct page *dpage;
+	uint64_t i = 0, j;
+	uint64_t addr;
+	int r = 0;
+
+	pr_debug("svms 0x%p [0x%lx 0x%lx]\n", prange->svms, prange->start,
+		 prange->last);
+
+	addr = prange->start << PAGE_SHIFT;
+
+	src = (uint64_t *)(scratch + npages);
+	dst = scratch;
+
+	for (i = 0, j = 0; i < npages; i++, addr += PAGE_SIZE) {
+		struct page *spage;
+
+		spage = migrate_pfn_to_page(migrate->src[i]);
+		if (!spage || !is_zone_device_page(spage)) {
+			pr_debug("invalid page. Could be in CPU already svms 0x%p [0x%lx 0x%lx]\n",
+				 prange->svms, prange->start, prange->last);
+			if (j) {
+				r = svm_migrate_copy_memory_gart(adev, dst + i - j,
+								 src + i - j, j,
+								 FROM_VRAM_TO_RAM,
+								 mfence);
+				if (r)
+					goto out_oom;
+				j = 0;
+			}
+			continue;
+		}
+		src[i] = svm_migrate_addr(adev, spage);
+		if (j > 0 && src[i] != src[i - 1] + PAGE_SIZE) {
+			r = svm_migrate_copy_memory_gart(adev, dst + i - j,
+							 src + i - j, j,
+							 FROM_VRAM_TO_RAM,
+							 mfence);
+			if (r)
+				goto out_oom;
+			j = 0;
+		}
+
+		dpage = svm_migrate_get_sys_page(migrate->vma, addr);
+		if (!dpage) {
+			pr_debug("failed get page svms 0x%p [0x%lx 0x%lx]\n",
+				 prange->svms, prange->start, prange->last);
+			r = -ENOMEM;
+			goto out_oom;
+		}
+
+		dst[i] = dma_map_page(dev, dpage, 0, PAGE_SIZE, DMA_FROM_DEVICE);
+		r = dma_mapping_error(dev, dst[i]);
+		if (r) {
+			dev_err(adev->dev, "%s: fail %d dma_map_page\n", __func__, r);
+			goto out_oom;
+		}
+
+		pr_debug_ratelimited("dma mapping dst to 0x%llx, pfn 0x%lx\n",
+				     dst[i] >> PAGE_SHIFT, page_to_pfn(dpage));
+
+		migrate->dst[i] = migrate_pfn(page_to_pfn(dpage));
+		j++;
+	}
+
+	r = svm_migrate_copy_memory_gart(adev, dst + i - j, src + i - j, j,
+					 FROM_VRAM_TO_RAM, mfence);
+
+out_oom:
+	if (r) {
+		pr_debug("failed %d copy to ram\n", r);
+		while (i--) {
+			svm_migrate_put_sys_page(dst[i]);
+			migrate->dst[i] = 0;
+		}
+	}
+
+	return r;
+}
+
+/**
+ * svm_migrate_vma_to_ram - migrate range inside one vma from device to system
+ *
+ * @prange: svm range structure
+ * @vma: vm_area_struct that range [start, end] belongs to
+ * @start: range start virtual address in pages
+ * @end: range end virtual address in pages
+ * @node: kfd node device to migrate from
+ * @trigger: reason of migration
+ * @fault_page: is from vmf->page, svm_migrate_to_ram(), this is CPU page fault callback
+ *
+ * Context: Process context, caller hold mmap read lock, prange->migrate_mutex
+ *
+ * Return:
+ *   0 - success with all pages migrated
+ *   negative values - indicate error
+ *   positive values - partial migration, number of pages not migrated
+ */
+static long
+svm_migrate_vma_to_ram(struct kfd_node *node, struct svm_range *prange,
+		       struct vm_area_struct *vma, uint64_t start, uint64_t end,
+		       uint32_t trigger, struct page *fault_page)
+{
+	struct kfd_process *p = container_of(prange->svms, struct kfd_process, svms);
+	uint64_t npages = (end - start) >> PAGE_SHIFT;
+	unsigned long upages = npages;
+	unsigned long cpages = 0;
+	struct amdgpu_device *adev = node->adev;
+	struct kfd_process_device *pdd;
+	struct dma_fence *mfence = NULL;
+	struct migrate_vma migrate = { 0 };
+	dma_addr_t *scratch;
+	void *buf;
+	int r = -ENOMEM;
+
+	memset(&migrate, 0, sizeof(migrate));
+	migrate.vma = vma;
+	migrate.start = start;
+	migrate.end = end;
+	migrate.pgmap_owner = SVM_ADEV_PGMAP_OWNER(adev);
+	if (adev->gmc.xgmi.connected_to_cpu)
+		migrate.flags = MIGRATE_VMA_SELECT_DEVICE_COHERENT;
+	else
+		migrate.flags = MIGRATE_VMA_SELECT_DEVICE_PRIVATE;
+
+	buf = kvcalloc(npages,
+		       2 * sizeof(*migrate.src) + sizeof(uint64_t) + sizeof(dma_addr_t),
+		       GFP_KERNEL);
+	if (!buf)
+		goto out;
+
+	migrate.src = buf;
+	migrate.dst = migrate.src + npages;
+	migrate.fault_page = fault_page;
+	scratch = (dma_addr_t *)(migrate.dst + npages);
+
+	kfd_smi_event_migration_start(node, p->lead_thread->pid,
+				      start >> PAGE_SHIFT, end >> PAGE_SHIFT,
+				      node->id, 0, prange->prefetch_loc,
+				      prange->preferred_loc, trigger);
+
+	r = migrate_vma_setup(&migrate);
+	if (r) {
+		dev_err(adev->dev, "%s: vma setup fail %d range [0x%lx 0x%lx]\n",
+			__func__, r, prange->start, prange->last);
+		goto out_free;
+	}
+
+	cpages = migrate.cpages;
+	if (!cpages) {
+		pr_debug("failed collect migrate device pages [0x%lx 0x%lx]\n",
+			 prange->start, prange->last);
+		upages = svm_migrate_unsuccessful_pages(&migrate);
+		goto out_free;
+	}
+	if (cpages != npages)
+		pr_debug("partial migration, 0x%lx/0x%llx pages migrated\n",
+			 cpages, npages);
+	else
+		pr_debug("0x%lx pages migrated\n", cpages);
+
+	r = svm_migrate_copy_to_ram(adev, prange, &migrate, &mfence,
+				    scratch, npages);
+	migrate_vma_pages(&migrate);
+
+	upages = svm_migrate_unsuccessful_pages(&migrate);
+	pr_debug("unsuccessful/cpages/npages 0x%lx/0x%lx/0x%lx\n",
+		 upages, cpages, migrate.npages);
+
+	svm_migrate_copy_done(adev, mfence);
+	migrate_vma_finalize(&migrate);
+
+	kfd_smi_event_migration_end(node, p->lead_thread->pid,
+				    start >> PAGE_SHIFT, end >> PAGE_SHIFT,
+				    node->id, 0, trigger);
+
+	svm_range_dma_unmap(adev->dev, scratch, 0, npages);
+
+out_free:
+	kvfree(buf);
+out:
+	if (!r && cpages) {
+		pdd = svm_range_get_pdd_by_node(prange, node);
+		if (pdd)
+			WRITE_ONCE(pdd->page_out, pdd->page_out + cpages);
+	}
+	return r ? r : upages;
+}
+
+/**
+ * svm_migrate_vram_to_ram - migrate svm range from device to system
+ * @prange: range structure
+ * @mm: process mm, use current->mm if NULL
+ * @trigger: reason of migration
+ * @fault_page: is from vmf->page, svm_migrate_to_ram(), this is CPU page fault callback
+ *
+ * Context: Process context, caller hold mmap read lock, prange->migrate_mutex
+ *
+ * Return:
+ * 0 - OK, otherwise error code
+ */
+int svm_migrate_vram_to_ram(struct svm_range *prange, struct mm_struct *mm,
+			    uint32_t trigger, struct page *fault_page)
+{
+	struct kfd_node *node;
+	struct vm_area_struct *vma;
+	unsigned long addr;
+	unsigned long start;
+	unsigned long end;
+	unsigned long upages = 0;
+	long r = 0;
+
+	if (!prange->actual_loc) {
+		pr_debug("[0x%lx 0x%lx] already migrated to ram\n",
+			 prange->start, prange->last);
+		return 0;
+	}
+
+	node = svm_range_get_node_by_id(prange, prange->actual_loc);
+	if (!node) {
+		pr_debug("failed to get kfd node by id 0x%x\n", prange->actual_loc);
+		return -ENODEV;
+	}
+	pr_debug("svms 0x%p prange 0x%p [0x%lx 0x%lx] from gpu 0x%x to ram\n",
+		 prange->svms, prange, prange->start, prange->last,
+		 prange->actual_loc);
+
+	start = prange->start << PAGE_SHIFT;
+	end = (prange->last + 1) << PAGE_SHIFT;
+
+	for (addr = start; addr < end;) {
+		unsigned long next;
+
+		vma = vma_lookup(mm, addr);
+		if (!vma) {
+			pr_debug("failed to find vma for prange %p\n", prange);
+			r = -EFAULT;
+			break;
+		}
+
+		next = min(vma->vm_end, end);
+		r = svm_migrate_vma_to_ram(node, prange, vma, addr, next, trigger,
+			fault_page);
+		if (r < 0) {
+			pr_debug("failed %ld to migrate prange %p\n", r, prange);
+			break;
+		} else {
+			upages += r;
+		}
+		addr = next;
+	}
+
+	if (r >= 0 && !upages) {
+		svm_range_vram_node_free(prange);
+		prange->actual_loc = 0;
+	}
+
+	return r < 0 ? r : 0;
+}
+
+/**
+ * svm_migrate_vram_to_vram - migrate svm range from device to device
+ * @prange: range structure
+ * @best_loc: the device to migrate to
+ * @mm: process mm, use current->mm if NULL
+ * @trigger: reason of migration
+ *
+ * Context: Process context, caller hold mmap read lock, svms lock, prange lock
+ *
+ * Return:
+ * 0 - OK, otherwise error code
+ */
+static int
+svm_migrate_vram_to_vram(struct svm_range *prange, uint32_t best_loc,
+			 struct mm_struct *mm, uint32_t trigger)
+{
+	int r, retries = 3;
+
+	/*
+	 * TODO: for both devices with PCIe large bar or on same xgmi hive, skip
+	 * system memory as migration bridge
+	 */
+
+	pr_debug("from gpu 0x%x to gpu 0x%x\n", prange->actual_loc, best_loc);
+
+	do {
+		r = svm_migrate_vram_to_ram(prange, mm, trigger, NULL);
+		if (r)
+			return r;
+	} while (prange->actual_loc && --retries);
+
+	if (prange->actual_loc)
+		return -EDEADLK;
+
+	return svm_migrate_ram_to_vram(prange, best_loc, mm, trigger);
+}
+
+int
+svm_migrate_to_vram(struct svm_range *prange, uint32_t best_loc,
+		    struct mm_struct *mm, uint32_t trigger)
+{
+	if  (!prange->actual_loc)
+		return svm_migrate_ram_to_vram(prange, best_loc, mm, trigger);
+	else
+		return svm_migrate_vram_to_vram(prange, best_loc, mm, trigger);
+
+}
+
+/**
+ * svm_migrate_to_ram - CPU page fault handler
+ * @vmf: CPU vm fault vma, address
+ *
+ * Context: vm fault handler, caller holds the mmap read lock
+ *
+ * Return:
+ * 0 - OK
+ * VM_FAULT_SIGBUS - notice application to have SIGBUS page fault
+ */
+static vm_fault_t svm_migrate_to_ram(struct vm_fault *vmf)
+{
+	unsigned long addr = vmf->address;
+	struct svm_range_bo *svm_bo;
+	enum svm_work_list_ops op;
+	struct svm_range *parent;
+	struct svm_range *prange;
+	struct kfd_process *p;
+	struct mm_struct *mm;
+	int r = 0;
+
+	svm_bo = vmf->page->zone_device_data;
+	if (!svm_bo) {
+		pr_debug("failed get device page at addr 0x%lx\n", addr);
+		return VM_FAULT_SIGBUS;
+	}
+	if (!mmget_not_zero(svm_bo->eviction_fence->mm)) {
+		pr_debug("addr 0x%lx of process mm is destroyed\n", addr);
+		return VM_FAULT_SIGBUS;
+	}
+
+	mm = svm_bo->eviction_fence->mm;
+	if (mm != vmf->vma->vm_mm)
+		pr_debug("addr 0x%lx is COW mapping in child process\n", addr);
+
+	p = kfd_lookup_process_by_mm(mm);
+	if (!p) {
+		pr_debug("failed find process at fault address 0x%lx\n", addr);
+		r = VM_FAULT_SIGBUS;
+		goto out_mmput;
+	}
+	if (READ_ONCE(p->svms.faulting_task) == current) {
+		pr_debug("skipping ram migration\n");
+		r = 0;
+		goto out_unref_process;
+	}
+
+	pr_debug("CPU page fault svms 0x%p address 0x%lx\n", &p->svms, addr);
+	addr >>= PAGE_SHIFT;
+
+	mutex_lock(&p->svms.lock);
+
+	prange = svm_range_from_addr(&p->svms, addr, &parent);
+	if (!prange) {
+		pr_debug("failed get range svms 0x%p addr 0x%lx\n", &p->svms, addr);
+		r = -EFAULT;
+		goto out_unlock_svms;
+	}
+
+	mutex_lock(&parent->migrate_mutex);
+	if (prange != parent)
+		mutex_lock_nested(&prange->migrate_mutex, 1);
+
+	if (!prange->actual_loc)
+		goto out_unlock_prange;
+
+	svm_range_lock(parent);
+	if (prange != parent)
+		mutex_lock_nested(&prange->lock, 1);
+	r = svm_range_split_by_granularity(p, mm, addr, parent, prange);
+	if (prange != parent)
+		mutex_unlock(&prange->lock);
+	svm_range_unlock(parent);
+	if (r) {
+		pr_debug("failed %d to split range by granularity\n", r);
+		goto out_unlock_prange;
+	}
+
+	r = svm_migrate_vram_to_ram(prange, vmf->vma->vm_mm,
+				    KFD_MIGRATE_TRIGGER_PAGEFAULT_CPU,
+				    vmf->page);
+	if (r)
+		pr_debug("failed %d migrate svms 0x%p range 0x%p [0x%lx 0x%lx]\n",
+			 r, prange->svms, prange, prange->start, prange->last);
+
+	/* xnack on, update mapping on GPUs with ACCESS_IN_PLACE */
+	if (p->xnack_enabled && parent == prange)
+		op = SVM_OP_UPDATE_RANGE_NOTIFIER_AND_MAP;
+	else
+		op = SVM_OP_UPDATE_RANGE_NOTIFIER;
+	svm_range_add_list_work(&p->svms, parent, mm, op);
+	schedule_deferred_list_work(&p->svms);
+
+out_unlock_prange:
+	if (prange != parent)
+		mutex_unlock(&prange->migrate_mutex);
+	mutex_unlock(&parent->migrate_mutex);
+out_unlock_svms:
+	mutex_unlock(&p->svms.lock);
+out_unref_process:
+	pr_debug("CPU fault svms 0x%p address 0x%lx done\n", &p->svms, addr);
+	kfd_unref_process(p);
+out_mmput:
+	mmput(mm);
+	return r ? VM_FAULT_SIGBUS : 0;
+}
+
+static const struct dev_pagemap_ops svm_migrate_pgmap_ops = {
+	.page_free		= svm_migrate_page_free,
+	.migrate_to_ram		= svm_migrate_to_ram,
+};
+
+/* Each VRAM page uses sizeof(struct page) on system memory */
+#define SVM_HMM_PAGE_STRUCT_SIZE(size) ((size)/PAGE_SIZE * sizeof(struct page))
+
+int kgd2kfd_init_zone_device(struct amdgpu_device *adev)
+{
+	struct amdgpu_kfd_dev *kfddev = &adev->kfd;
+	struct dev_pagemap *pgmap;
+	struct resource *res = NULL;
+	unsigned long size;
+	void *r;
+
+	/* Page migration works on gfx9 or newer */
+	if (adev->ip_versions[GC_HWIP][0] < IP_VERSION(9, 0, 1))
+		return -EINVAL;
+
+	if (adev->gmc.is_app_apu)
+		return 0;
+
+	pgmap = &kfddev->pgmap;
+	memset(pgmap, 0, sizeof(*pgmap));
+
+	/* TODO: register all vram to HMM for now.
+	 * should remove reserved size
+	 */
+	size = ALIGN(adev->gmc.real_vram_size, 2ULL << 20);
+	if (adev->gmc.xgmi.connected_to_cpu) {
+		pgmap->range.start = adev->gmc.aper_base;
+		pgmap->range.end = adev->gmc.aper_base + adev->gmc.aper_size - 1;
+		pgmap->type = MEMORY_DEVICE_COHERENT;
+	} else {
+		res = devm_request_free_mem_region(adev->dev, &iomem_resource, size);
+		if (IS_ERR(res))
+			return PTR_ERR(res);
+		pgmap->range.start = res->start;
+		pgmap->range.end = res->end;
+		pgmap->type = MEMORY_DEVICE_PRIVATE;
+	}
+
+	pgmap->nr_range = 1;
+	pgmap->ops = &svm_migrate_pgmap_ops;
+	pgmap->owner = SVM_ADEV_PGMAP_OWNER(adev);
+	pgmap->flags = 0;
+	/* Device manager releases device-specific resources, memory region and
+	 * pgmap when driver disconnects from device.
+	 */
+	r = devm_memremap_pages(adev->dev, pgmap);
+	if (IS_ERR(r)) {
+		pr_err("failed to register HMM device memory\n");
+		if (pgmap->type == MEMORY_DEVICE_PRIVATE)
+			devm_release_mem_region(adev->dev, res->start, resource_size(res));
+		/* Disable SVM support capability */
+		pgmap->type = 0;
+		return PTR_ERR(r);
+	}
+
+	pr_debug("reserve %ldMB system memory for VRAM pages struct\n",
+		 SVM_HMM_PAGE_STRUCT_SIZE(size) >> 20);
+
+	amdgpu_amdkfd_reserve_system_mem(SVM_HMM_PAGE_STRUCT_SIZE(size));
+
+	pr_info("HMM registered %ldMB device memory\n", size >> 20);
+
+	return 0;
+}