drm/amdgpu: Implement mmap as GEM object function

Moving the driver-specific mmap code into a GEM object function allows
for using DRM helpers for various mmap callbacks.

This change resolves several inconsistencies between regular mmap and
prime-based mmap. The vm_ops field in vma is now set for all mmap'ed
areas. Previously it way only set for regular mmap calls, prime-based
mmap used TTM's default vm_ops. The function amdgpu_verify_access() is
no longer being called and therefore removed by this patch.

As a side effect, amdgpu_ttm_vm_ops and amdgpu_ttm_fault() are now
implemented in amdgpu's GEM code.

v4:
	* rebased
v3:
	* rename mmap function to amdgpu_gem_object_mmap() (Christian)
	* remove unnecessary checks from mmap (Christian)
v2:
	* rename amdgpu_ttm_vm_ops and amdgpu_ttm_fault() to
	  amdgpu_gem_vm_ops and amdgpu_gem_fault() (Christian)
	* the check for kfd_bo has meanwhile been removed

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Christian König <christian.koenig@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210525151055.8174-3-tzimmermann@suse.de

drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c

@@ -42,52 +42,6 @@
 #include <linux/pci-p2pdma.h>
 #include <linux/pm_runtime.h>
 
-/**
- * amdgpu_gem_prime_mmap - &drm_driver.gem_prime_mmap implementation
- * @obj: GEM BO
- * @vma: Virtual memory area
- *
- * Sets up a userspace mapping of the BO's memory in the given
- * virtual memory area.
- *
- * Returns:
- * 0 on success or a negative error code on failure.
- */
-int amdgpu_gem_prime_mmap(struct drm_gem_object *obj,
-			  struct vm_area_struct *vma)
-{
-	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
-	struct amdgpu_device *adev = amdgpu_ttm_adev(bo->tbo.bdev);
-	unsigned asize = amdgpu_bo_size(bo);
-	int ret;
-
-	if (!vma->vm_file)
-		return -ENODEV;
-
-	if (adev == NULL)
-		return -ENODEV;
-
-	/* Check for valid size. */
-	if (asize < vma->vm_end - vma->vm_start)
-		return -EINVAL;
-
-	if (amdgpu_ttm_tt_get_usermm(bo->tbo.ttm) ||
-	    (bo->flags & AMDGPU_GEM_CREATE_NO_CPU_ACCESS)) {
-		return -EPERM;
-	}
-	vma->vm_pgoff += amdgpu_bo_mmap_offset(bo) >> PAGE_SHIFT;
-
-	/* prime mmap does not need to check access, so allow here */
-	ret = drm_vma_node_allow(&obj->vma_node, vma->vm_file->private_data);
-	if (ret)
-		return ret;
-
-	ret = ttm_bo_mmap(vma->vm_file, vma, &adev->mman.bdev);
-	drm_vma_node_revoke(&obj->vma_node, vma->vm_file->private_data);
-
-	return ret;
-}
-
 static int
 __dma_resv_make_exclusive(struct dma_resv *obj)
 {

drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.h

@@ -31,8 +31,6 @@ struct drm_gem_object *amdgpu_gem_prime_import(struct drm_device *dev,
 					    struct dma_buf *dma_buf);
 bool amdgpu_dmabuf_is_xgmi_accessible(struct amdgpu_device *adev,
 				      struct amdgpu_bo *bo);
-int amdgpu_gem_prime_mmap(struct drm_gem_object *obj,
-			  struct vm_area_struct *vma);
 
 extern const struct dma_buf_ops amdgpu_dmabuf_ops;
 

drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c

@@ -1695,7 +1695,7 @@ static const struct file_operations amdgpu_driver_kms_fops = {
 	.flush = amdgpu_flush,
 	.release = drm_release,
 	.unlocked_ioctl = amdgpu_drm_ioctl,
-	.mmap = amdgpu_mmap,
+	.mmap = drm_gem_mmap,
 	.poll = drm_poll,
 	.read = drm_read,
 #ifdef CONFIG_COMPAT
@@ -1762,7 +1762,7 @@ static const struct drm_driver amdgpu_kms_driver = {
 	.prime_handle_to_fd = drm_gem_prime_handle_to_fd,
 	.prime_fd_to_handle = drm_gem_prime_fd_to_handle,
 	.gem_prime_import = amdgpu_gem_prime_import,
-	.gem_prime_mmap = amdgpu_gem_prime_mmap,
+	.gem_prime_mmap = drm_gem_prime_mmap,
 
 	.name = DRIVER_NAME,
 	.desc = DRIVER_DESC,

drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c

@@ -32,6 +32,7 @@
 #include <linux/dma-buf.h>
 
 #include <drm/amdgpu_drm.h>
+#include <drm/drm_drv.h>
 #include <drm/drm_gem_ttm_helper.h>
 
 #include "amdgpu.h"
@@ -41,6 +42,46 @@
 
 static const struct drm_gem_object_funcs amdgpu_gem_object_funcs;
 
+static vm_fault_t amdgpu_gem_fault(struct vm_fault *vmf)
+{
+	struct ttm_buffer_object *bo = vmf->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;
+
+	if (drm_dev_enter(ddev, &idx)) {
+		ret = amdgpu_bo_fault_reserve_notify(bo);
+		if (ret) {
+			drm_dev_exit(idx);
+			goto unlock;
+		}
+
+		 ret = ttm_bo_vm_fault_reserved(vmf, vmf->vma->vm_page_prot,
+						TTM_BO_VM_NUM_PREFAULT, 1);
+
+		 drm_dev_exit(idx);
+	} else {
+		ret = ttm_bo_vm_dummy_page(vmf, vmf->vma->vm_page_prot);
+	}
+	if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT))
+		return ret;
+
+unlock:
+	dma_resv_unlock(bo->base.resv);
+	return ret;
+}
+
+static const struct vm_operations_struct amdgpu_gem_vm_ops = {
+	.fault = amdgpu_gem_fault,
+	.open = ttm_bo_vm_open,
+	.close = ttm_bo_vm_close,
+	.access = ttm_bo_vm_access
+};
+
 static void amdgpu_gem_object_free(struct drm_gem_object *gobj)
 {
 	struct amdgpu_bo *robj = gem_to_amdgpu_bo(gobj);
@@ -205,6 +246,18 @@ out_unlock:
 	ttm_eu_backoff_reservation(&ticket, &list);
 }
 
+static int amdgpu_gem_object_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
+{
+	struct amdgpu_bo *bo = gem_to_amdgpu_bo(obj);
+
+	if (amdgpu_ttm_tt_get_usermm(bo->tbo.ttm))
+		return -EPERM;
+	if (bo->flags & AMDGPU_GEM_CREATE_NO_CPU_ACCESS)
+		return -EPERM;
+
+	return drm_gem_ttm_mmap(obj, vma);
+}
+
 static const struct drm_gem_object_funcs amdgpu_gem_object_funcs = {
 	.free = amdgpu_gem_object_free,
 	.open = amdgpu_gem_object_open,
@@ -212,6 +265,8 @@ static const struct drm_gem_object_funcs amdgpu_gem_object_funcs = {
 	.export = amdgpu_gem_prime_export,
 	.vmap = drm_gem_ttm_vmap,
 	.vunmap = drm_gem_ttm_vunmap,
+	.mmap = amdgpu_gem_object_mmap,
+	.vm_ops = &amdgpu_gem_vm_ops,
 };
 
 /*

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c

@@ -47,7 +47,6 @@
 #include <drm/ttm/ttm_placement.h>
 
 #include <drm/amdgpu_drm.h>
-#include <drm/drm_drv.h>
 
 #include "amdgpu.h"
 #include "amdgpu_object.h"
@@ -166,25 +165,6 @@ static void amdgpu_evict_flags(struct ttm_buffer_object *bo,
 	*placement = abo->placement;
 }
 
-/**
- * amdgpu_verify_access - Verify access for a mmap call
- *
- * @bo:	The buffer object to map
- * @filp: The file pointer from the process performing the mmap
- *
- * This is called by ttm_bo_mmap() to verify whether a process
- * has the right to mmap a BO to their process space.
- */
-static int amdgpu_verify_access(struct ttm_buffer_object *bo, struct file *filp)
-{
-	struct amdgpu_bo *abo = ttm_to_amdgpu_bo(bo);
-
-	if (amdgpu_ttm_tt_get_usermm(bo->ttm))
-		return -EPERM;
-	return drm_vma_node_verify_access(&abo->tbo.base.vma_node,
-					  filp->private_data);
-}
-
 /**
  * amdgpu_ttm_map_buffer - Map memory into the GART windows
  * @bo: buffer object to map
@@ -1476,7 +1456,6 @@ static struct ttm_device_funcs amdgpu_bo_driver = {
 	.eviction_valuable = amdgpu_ttm_bo_eviction_valuable,
 	.evict_flags = &amdgpu_evict_flags,
 	.move = &amdgpu_bo_move,
-	.verify_access = &amdgpu_verify_access,
 	.delete_mem_notify = &amdgpu_bo_delete_mem_notify,
 	.release_notify = &amdgpu_bo_release_notify,
 	.io_mem_reserve = &amdgpu_ttm_io_mem_reserve,
@@ -1844,60 +1823,6 @@ void amdgpu_ttm_set_buffer_funcs_status(struct amdgpu_device *adev, bool enable)
 	adev->mman.buffer_funcs_enabled = enable;
 }
 
-static vm_fault_t amdgpu_ttm_fault(struct vm_fault *vmf)
-{
-	struct ttm_buffer_object *bo = vmf->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;
-
-	if (drm_dev_enter(ddev, &idx)) {
-		ret = amdgpu_bo_fault_reserve_notify(bo);
-		if (ret) {
-			drm_dev_exit(idx);
-			goto unlock;
-		}
-
-		 ret = ttm_bo_vm_fault_reserved(vmf, vmf->vma->vm_page_prot,
-						TTM_BO_VM_NUM_PREFAULT, 1);
-
-		 drm_dev_exit(idx);
-	} else {
-		ret = ttm_bo_vm_dummy_page(vmf, vmf->vma->vm_page_prot);
-	}
-	if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT))
-		return ret;
-
-unlock:
-	dma_resv_unlock(bo->base.resv);
-	return ret;
-}
-
-static const struct vm_operations_struct amdgpu_ttm_vm_ops = {
-	.fault = amdgpu_ttm_fault,
-	.open = ttm_bo_vm_open,
-	.close = ttm_bo_vm_close,
-	.access = ttm_bo_vm_access
-};
-
-int amdgpu_mmap(struct file *filp, struct vm_area_struct *vma)
-{
-	struct drm_file *file_priv = filp->private_data;
-	struct amdgpu_device *adev = drm_to_adev(file_priv->minor->dev);
-	int r;
-
-	r = ttm_bo_mmap(filp, vma, &adev->mman.bdev);
-	if (unlikely(r != 0))
-		return r;
-
-	vma->vm_ops = &amdgpu_ttm_vm_ops;
-	return 0;
-}
-
 int amdgpu_copy_buffer(struct amdgpu_ring *ring, uint64_t src_offset,
 		       uint64_t dst_offset, uint32_t byte_count,
 		       struct dma_resv *resv,

drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h

@@ -142,7 +142,6 @@ int amdgpu_fill_buffer(struct amdgpu_bo *bo,
 			struct dma_resv *resv,
 			struct dma_fence **fence);
 
-int amdgpu_mmap(struct file *filp, struct vm_area_struct *vma);
 int amdgpu_ttm_alloc_gart(struct ttm_buffer_object *bo);
 int amdgpu_ttm_recover_gart(struct ttm_buffer_object *tbo);
 uint64_t amdgpu_ttm_domain_start(struct amdgpu_device *adev, uint32_t type);