On device removal reroute all CPU mappings to dummy page.
v3: Remove loop to find DRM file and instead access it by vma->vm_file->private_data. Move dummy page installation into a separate function.
v4: Map the entire BOs VA space into on demand allocated dummy page on the first fault for that BO.
v5: Remove duplicate return.
Signed-off-by: Andrey Grodzovsky andrey.grodzovsky@amd.com --- drivers/gpu/drm/ttm/ttm_bo_vm.c | 79 ++++++++++++++++++++++++++++++++- include/drm/ttm/ttm_bo_api.h | 2 + 2 files changed, 80 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c index b31b18058965..8b8300551a7f 100644 --- a/drivers/gpu/drm/ttm/ttm_bo_vm.c +++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c @@ -34,6 +34,8 @@ #include <drm/ttm/ttm_bo_driver.h> #include <drm/ttm/ttm_placement.h> #include <drm/drm_vma_manager.h> +#include <drm/drm_drv.h> +#include <drm/drm_managed.h> #include <linux/mm.h> #include <linux/pfn_t.h> #include <linux/rbtree.h> @@ -380,19 +382,94 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf, } EXPORT_SYMBOL(ttm_bo_vm_fault_reserved);
+static void ttm_bo_release_dummy_page(struct drm_device *dev, void *res) +{ + struct page *dummy_page = (struct page *)res; + + __free_page(dummy_page); +} + +vm_fault_t ttm_bo_vm_dummy_page(struct vm_fault *vmf, pgprot_t prot) +{ + struct vm_area_struct *vma = vmf->vma; + struct ttm_buffer_object *bo = vma->vm_private_data; + struct drm_device *ddev = bo->base.dev; + vm_fault_t ret = VM_FAULT_NOPAGE; + unsigned long address = vma->vm_start; + unsigned long num_prefault = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT; + unsigned long pfn; + struct page *page; + int i; + + /* + * Wait for buffer data in transit, due to a pipelined + * move. + */ + ret = ttm_bo_vm_fault_idle(bo, vmf); + if (unlikely(ret != 0)) + return ret; + + /* Allocate new dummy page to map all the VA range in this VMA to it*/ + page = alloc_page(GFP_KERNEL | __GFP_ZERO); + if (!page) + return VM_FAULT_OOM; + + pfn = page_to_pfn(page); + + /* + * Prefault the entire VMA range right away to avoid further faults + */ + for (i = 0; i < num_prefault; ++i) { + + if (unlikely(address >= vma->vm_end)) + break; + + if (vma->vm_flags & VM_MIXEDMAP) + ret = vmf_insert_mixed_prot(vma, address, + __pfn_to_pfn_t(pfn, PFN_DEV), + prot); + else + ret = vmf_insert_pfn_prot(vma, address, pfn, prot); + + /* Never error on prefaulted PTEs */ + if (unlikely((ret & VM_FAULT_ERROR))) { + if (i == 0) + return VM_FAULT_NOPAGE; + else + break; + } + + address += PAGE_SIZE; + } + + /* Set the page to be freed using drmm release action */ + if (drmm_add_action_or_reset(ddev, ttm_bo_release_dummy_page, page)) + return VM_FAULT_OOM; + + return ret; +} +EXPORT_SYMBOL(ttm_bo_vm_dummy_page); + vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf) { struct vm_area_struct *vma = vmf->vma; pgprot_t prot; struct ttm_buffer_object *bo = vma->vm_private_data; + struct drm_device *ddev = bo->base.dev; vm_fault_t ret; + int idx;
ret = ttm_bo_vm_reserve(bo, vmf); if (ret) return ret;
prot = vma->vm_page_prot; - ret = ttm_bo_vm_fault_reserved(vmf, prot, TTM_BO_VM_NUM_PREFAULT, 1); + if (drm_dev_enter(ddev, &idx)) { + ret = ttm_bo_vm_fault_reserved(vmf, prot, TTM_BO_VM_NUM_PREFAULT, 1); + drm_dev_exit(idx); + } else { + ret = ttm_bo_vm_dummy_page(vmf, prot); + } if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) return ret;
diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h index 3587f660e8f4..dbb00e495cb4 100644 --- a/include/drm/ttm/ttm_bo_api.h +++ b/include/drm/ttm/ttm_bo_api.h @@ -635,4 +635,6 @@ int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr, void *buf, int len, int write); bool ttm_bo_delayed_delete(struct ttm_device *bdev, bool remove_all);
+vm_fault_t ttm_bo_vm_dummy_page(struct vm_fault *vmf, pgprot_t prot); + #endif