On Mon, Jan 18, 2021 at 4:02 PM Andrey Grodzovsky andrey.grodzovsky@amd.com wrote:
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.
Signed-off-by: Andrey Grodzovsky andrey.grodzovsky@amd.com
drivers/gpu/drm/ttm/ttm_bo_vm.c | 82 ++++++++++++++++++++++++++++++++++++++++- include/drm/ttm/ttm_bo_api.h | 2 + 2 files changed, 83 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c index 6dc96cf..ed89da3 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> @@ -380,25 +382,103 @@ 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 ttm_bo_device *bdev = bo->bdev;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);elseret = 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;elsebreak;}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; dma_resv_unlock(bo->base.resv); return ret;return ret;
Duplicate return here.
Alex
} EXPORT_SYMBOL(ttm_bo_vm_fault);
diff --git a/include/drm/ttm/ttm_bo_api.h b/include/drm/ttm/ttm_bo_api.h index e17be32..12fb240 100644 --- a/include/drm/ttm/ttm_bo_api.h +++ b/include/drm/ttm/ttm_bo_api.h @@ -643,4 +643,6 @@ void ttm_bo_vm_close(struct vm_area_struct *vma); int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr, void *buf, int len, int write);
+vm_fault_t ttm_bo_vm_dummy_page(struct vm_fault *vmf, pgprot_t prot);
#endif
2.7.4
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