[PATCH 6/7] nouveau/dmem: Evict device private memory during release
From: Alistair Popple <apopple@nvidia.com>
Date: 2022-09-26 06:05:31
Also in:
amd-gfx, dri-devel, linux-mm, lkml, nouveau
Subsystem:
drm driver for nvidia geforce/quadro gpus, drm drivers, drm drivers and misc gpu patches, the rest · Maintainers:
Lyude Paul, Danilo Krummrich, David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Linus Torvalds
When the module is unloaded or a GPU is unbound from the module it is possible for device private pages to be left mapped in currently running processes. This leads to a kernel crash when the pages are either freed or accessed from the CPU because the GPU and associated data structures and callbacks have all been freed. Fix this by migrating any mappings back to normal CPU memory prior to freeing the GPU memory chunks and associated device private pages. Signed-off-by: Alistair Popple <apopple@nvidia.com> --- I assume the AMD driver might have a similar issue. However I can't see where device private (or coherent) pages actually get unmapped/freed during teardown as I couldn't find any relevant calls to devm_memunmap(), memunmap(), devm_release_mem_region() or release_mem_region(). So it appears that ZONE_DEVICE pages are not being properly freed during module unload, unless I'm missing something? --- drivers/gpu/drm/nouveau/nouveau_dmem.c | 48 +++++++++++++++++++++++++++- 1 file changed, 48 insertions(+)
diff --git a/drivers/gpu/drm/nouveau/nouveau_dmem.c b/drivers/gpu/drm/nouveau/nouveau_dmem.c
index 66ebbd4..3b247b8 100644
--- a/drivers/gpu/drm/nouveau/nouveau_dmem.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dmem.c@@ -369,6 +369,52 @@ nouveau_dmem_suspend(struct nouveau_drm *drm) mutex_unlock(&drm->dmem->mutex); } +/* + * Evict all pages mapping a chunk. + */ +void +nouveau_dmem_evict_chunk(struct nouveau_dmem_chunk *chunk) +{ + unsigned long i, npages = range_len(&chunk->pagemap.range) >> PAGE_SHIFT; + unsigned long *src_pfns, *dst_pfns; + dma_addr_t *dma_addrs; + struct nouveau_fence *fence; + + src_pfns = kcalloc(npages, sizeof(*src_pfns), GFP_KERNEL); + dst_pfns = kcalloc(npages, sizeof(*dst_pfns), GFP_KERNEL); + dma_addrs = kcalloc(npages, sizeof(*dma_addrs), GFP_KERNEL); + + migrate_device_range(src_pfns, chunk->pagemap.range.start >> PAGE_SHIFT, + npages); + + for (i = 0; i < npages; i++) { + if (src_pfns[i] & MIGRATE_PFN_MIGRATE) { + struct page *dpage; + + /* + * _GFP_NOFAIL because the GPU is going away and there + * is nothing sensible we can do if we can't copy the + * data back. + */ + dpage = alloc_page(GFP_HIGHUSER | __GFP_NOFAIL); + dst_pfns[i] = migrate_pfn(page_to_pfn(dpage)); + nouveau_dmem_copy_one(chunk->drm, + migrate_pfn_to_page(src_pfns[i]), dpage, + &dma_addrs[i]); + } + } + + nouveau_fence_new(chunk->drm->dmem->migrate.chan, false, &fence); + migrate_device_pages(src_pfns, dst_pfns, npages); + nouveau_dmem_fence_done(&fence); + migrate_device_finalize(src_pfns, dst_pfns, npages); + kfree(src_pfns); + kfree(dst_pfns); + for (i = 0; i < npages; i++) + dma_unmap_page(chunk->drm->dev->dev, dma_addrs[i], PAGE_SIZE, DMA_BIDIRECTIONAL); + kfree(dma_addrs); +} + void nouveau_dmem_fini(struct nouveau_drm *drm) {
@@ -380,8 +426,10 @@ nouveau_dmem_fini(struct nouveau_drm *drm) mutex_lock(&drm->dmem->mutex); list_for_each_entry_safe(chunk, tmp, &drm->dmem->chunks, list) { + nouveau_dmem_evict_chunk(chunk); nouveau_bo_unpin(chunk->bo); nouveau_bo_ref(NULL, &chunk->bo); + WARN_ON(chunk->callocated); list_del(&chunk->list); memunmap_pages(&chunk->pagemap); release_mem_region(chunk->pagemap.range.start,
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