Re: [Intel-gfx] [PATCH v2 13/15] drm/ttm: Add BO and offset arguments for vm_access and vm_fault ttm handlers.

Tue, 18 May 2021 07:59:59 -0700 


On 5/18/21 1:59 PM, Christian König wrote:

Can you send me the patch directly and not just on CC?

Thanks,
Christian.


Original patch sent. Pls remember to CC lists on reply, though.
The reason we need this is because of i915's strange mmap functionality which allows a bo to be mapped at multiple offsets and  the vma->private is not a bo... 

Thanks,

Thomas






Am 18.05.21 um 10:59 schrieb Thomas Hellström:

+ Christian König

On 5/18/21 10:26 AM, Thomas Hellström wrote:

From: Maarten Lankhorst <maarten.lankho...@linux.intel.com>

This allows other drivers that may not setup the vma in the same way
to use the ttm bo helpers.
Also clarify the documentation a bit, especially related to VM_FAULT_RETRY. 

Signed-off-by: Maarten Lankhorst <maarten.lankho...@linux.intel.com>


Lgtm. Reviewed-by: Thomas Hellström <thomas.hellst...@linux.intel.com>


---
  drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c    |  4 +-
  drivers/gpu/drm/nouveau/nouveau_ttm.c      |  4 +-
  drivers/gpu/drm/radeon/radeon_ttm.c        |  4 +-
  drivers/gpu/drm/ttm/ttm_bo_vm.c            | 84 +++++++++++++--------- 
  drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c |  8 ++-
  include/drm/ttm/ttm_bo_api.h               |  9 ++-
  6 files changed, 75 insertions(+), 38 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c 
index d5a9d7a88315..89dafe14f828 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1919,7 +1919,9 @@ static vm_fault_t amdgpu_ttm_fault(struct vm_fault *vmf) 
      if (ret)
          goto unlock;
  -    ret = ttm_bo_vm_fault_reserved(vmf, vmf->vma->vm_page_prot,
+    ret = ttm_bo_vm_fault_reserved(bo, vmf,
+ drm_vma_node_start(&bo->base.vma_node),
+                       vmf->vma->vm_page_prot,
                         TTM_BO_VM_NUM_PREFAULT, 1);
      if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) 
          return ret;
diff --git a/drivers/gpu/drm/nouveau/nouveau_ttm.c b/drivers/gpu/drm/nouveau/nouveau_ttm.c 
index b81ae90b8449..555fb6d8be8b 100644
--- a/drivers/gpu/drm/nouveau/nouveau_ttm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_ttm.c
@@ -144,7 +144,9 @@ static vm_fault_t nouveau_ttm_fault(struct vm_fault *vmf) 
        nouveau_bo_del_io_reserve_lru(bo);
      prot = vm_get_page_prot(vma->vm_flags);
-    ret = ttm_bo_vm_fault_reserved(vmf, prot, TTM_BO_VM_NUM_PREFAULT, 1); 
+    ret = ttm_bo_vm_fault_reserved(bo, vmf,
+ drm_vma_node_start(&bo->base.vma_node),
+                       prot, TTM_BO_VM_NUM_PREFAULT, 1);
      nouveau_bo_add_io_reserve_lru(bo);
      if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) 
          return ret;
diff --git a/drivers/gpu/drm/radeon/radeon_ttm.c b/drivers/gpu/drm/radeon/radeon_ttm.c 
index 3361d11769a2..ba48a2acdef0 100644
--- a/drivers/gpu/drm/radeon/radeon_ttm.c
+++ b/drivers/gpu/drm/radeon/radeon_ttm.c
@@ -816,7 +816,9 @@ static vm_fault_t radeon_ttm_fault(struct vm_fault *vmf) 
      if (ret)
          goto unlock_resv;
  -    ret = ttm_bo_vm_fault_reserved(vmf, vmf->vma->vm_page_prot,
+    ret = ttm_bo_vm_fault_reserved(bo, vmf,
+ drm_vma_node_start(&bo->base.vma_node),
+                       vmf->vma->vm_page_prot,
                         TTM_BO_VM_NUM_PREFAULT, 1);
      if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) 
          goto unlock_mclk;
diff --git a/drivers/gpu/drm/ttm/ttm_bo_vm.c b/drivers/gpu/drm/ttm/ttm_bo_vm.c 
index b31b18058965..ed00ccf1376e 100644
--- a/drivers/gpu/drm/ttm/ttm_bo_vm.c
+++ b/drivers/gpu/drm/ttm/ttm_bo_vm.c
@@ -42,7 +42,7 @@
  #include <linux/mem_encrypt.h>
    static vm_fault_t ttm_bo_vm_fault_idle(struct ttm_buffer_object *bo, 
-                struct vm_fault *vmf)
+                       struct vm_fault *vmf)
  {
      vm_fault_t ret = 0;
      int err = 0;
@@ -122,7 +122,8 @@ static unsigned long ttm_bo_io_mem_pfn(struct ttm_buffer_object *bo, 
   * Return:
   *    0 on success and the bo was reserved.
   *    VM_FAULT_RETRY if blocking wait.
- *    VM_FAULT_NOPAGE if blocking wait and retrying was not allowed.
+ *    VM_FAULT_NOPAGE if blocking wait and retrying was not allowed, or wait interrupted. + *    VM_FAULT_SIGBUS if wait on bo->moving failed for reason other than a signal. 
   */
  vm_fault_t ttm_bo_vm_reserve(struct ttm_buffer_object *bo,
                   struct vm_fault *vmf)
@@ -254,7 +255,9 @@ static vm_fault_t ttm_bo_vm_insert_huge(struct vm_fault *vmf, 
    /**
   * ttm_bo_vm_fault_reserved - TTM fault helper
+ * @bo: The buffer object
   * @vmf: The struct vm_fault given as argument to the fault callback
+ * @mmap_base: The base of the mmap, to which the @vmf fault is relative to. 
   * @prot: The page protection to be used for this memory area.
   * @num_prefault: Maximum number of prefault pages. The caller may want to    * specify this based on madvice settings and the size of the GPU object @@ -265,19 +268,28 @@ static vm_fault_t ttm_bo_vm_insert_huge(struct vm_fault *vmf, 
   * memory backing the buffer object, and then returns a return code
   * instructing the caller to retry the page access.
   *
+ * This function ensures any pipelined wait is finished.
+ *
+ * WARNING:
+ * On VM_FAULT_RETRY, the bo will be unlocked by this function when
+ * #FAULT_FLAG_RETRY_NOWAIT is not set inside @vmf->flags. In this
+ * case, the caller should not unlock the @bo.
+ *
   * Return:
- *   VM_FAULT_NOPAGE on success or pending signal
+ *   0 on success.
+ *   VM_FAULT_NOPAGE on pending signal
   *   VM_FAULT_SIGBUS on unspecified error
   *   VM_FAULT_OOM on out-of-memory
- *   VM_FAULT_RETRY if retryable wait
+ *   VM_FAULT_RETRY if retryable wait, see WARNING above.
   */
-vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf,
+vm_fault_t ttm_bo_vm_fault_reserved(struct ttm_buffer_object *bo,
+                    struct vm_fault *vmf,
+                    unsigned long mmap_base,
                      pgprot_t prot,
                      pgoff_t num_prefault,
                      pgoff_t fault_page_size)
  {
      struct vm_area_struct *vma = vmf->vma;
-    struct ttm_buffer_object *bo = vma->vm_private_data;
      struct ttm_device *bdev = bo->bdev;
      unsigned long page_offset;
      unsigned long page_last;
@@ -286,15 +298,11 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf, 
      struct page *page;
      int err;
      pgoff_t i;
-    vm_fault_t ret = VM_FAULT_NOPAGE;
+    vm_fault_t ret;
      unsigned long address = vmf->address;
  -    /*
-     * Wait for buffer data in transit, due to a pipelined
-     * move.
-     */
      ret = ttm_bo_vm_fault_idle(bo, vmf);
-    if (unlikely(ret != 0))
+    if (ret)
          return ret;
        err = ttm_mem_io_reserve(bdev, &bo->mem);
@@ -302,9 +310,8 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf, 
          return VM_FAULT_SIGBUS;
        page_offset = ((address - vma->vm_start) >> PAGE_SHIFT) +
-        vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node);
-    page_last = vma_pages(vma) + vma->vm_pgoff -
-        drm_vma_node_start(&bo->base.vma_node);
+        vma->vm_pgoff - mmap_base;
+    page_last = vma_pages(vma) + vma->vm_pgoff - mmap_base;
        if (unlikely(page_offset >= bo->mem.num_pages))
          return VM_FAULT_SIGBUS;
@@ -344,8 +351,7 @@ vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf, 
              } else if (unlikely(!page)) {
                  break;
              }
-            page->index = drm_vma_node_start(&bo->base.vma_node) +
-                page_offset;
+            page->index = mmap_base + page_offset;
              pfn = page_to_pfn(page);
          }
  @@ -392,7 +398,10 @@ vm_fault_t ttm_bo_vm_fault(struct vm_fault *vmf)
          return ret;
        prot = vma->vm_page_prot;
-    ret = ttm_bo_vm_fault_reserved(vmf, prot, TTM_BO_VM_NUM_PREFAULT, 1); 
+    ret = ttm_bo_vm_fault_reserved(bo, vmf,
+ drm_vma_node_start(&bo->base.vma_node),
+                       prot, TTM_BO_VM_NUM_PREFAULT, 1);
+
      if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) 
          return ret;
  @@ -460,22 +469,16 @@ static int ttm_bo_vm_access_kmap(struct ttm_buffer_object *bo, 
      return len;
  }
  -int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
-             void *buf, int len, int write)
+int ttm_bo_vm_access_reserved(struct ttm_buffer_object *bo,
+                  struct vm_area_struct *vma,
+                  unsigned long offset,
+                  void *buf, int len, int write)
  {
-    struct ttm_buffer_object *bo = vma->vm_private_data;
-    unsigned long offset = (addr) - vma->vm_start +
-        ((vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node))
-         << PAGE_SHIFT);
      int ret;
        if (len < 1 || (offset + len) >> PAGE_SHIFT > bo->mem.num_pages) 
          return -EIO;
  -    ret = ttm_bo_reserve(bo, true, false, NULL);
-    if (ret)
-        return ret;
-
      switch (bo->mem.mem_type) {
      case TTM_PL_SYSTEM:
          if (unlikely(bo->ttm->page_flags & TTM_PAGE_FLAG_SWAPPED)) {
@@ -485,16 +488,33 @@ int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr, 
          }
          fallthrough;
      case TTM_PL_TT:
-        ret = ttm_bo_vm_access_kmap(bo, offset, buf, len, write);
-        break;
+        return ttm_bo_vm_access_kmap(bo, offset, buf, len, write);
      default:
          if (bo->bdev->funcs->access_memory)
-            ret = bo->bdev->funcs->access_memory(
+            return bo->bdev->funcs->access_memory(
                  bo, offset, buf, len, write);
          else
-            ret = -EIO;
+            return -EIO;
      }
  +    return ret;
+}
+EXPORT_SYMBOL(ttm_bo_vm_access_reserved);
+
+int ttm_bo_vm_access(struct vm_area_struct *vma, unsigned long addr,
+             void *buf, int len, int write)
+{
+    struct ttm_buffer_object *bo = vma->vm_private_data;
+    unsigned long offset = (addr) - vma->vm_start +
+        ((vma->vm_pgoff - drm_vma_node_start(&bo->base.vma_node))
+         << PAGE_SHIFT);
+    int ret;
+
+    ret = ttm_bo_reserve(bo, true, false, NULL);
+    if (ret)
+        return ret;
+
+    ret = ttm_bo_vm_access_reserved(bo, vma, offset, buf, len, write);
      ttm_bo_unreserve(bo);
        return ret;
diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c b/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c 
index 45c9c6a7f1d6..56ecace0cf5c 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_page_dirty.c
@@ -477,7 +477,9 @@ vm_fault_t vmw_bo_vm_fault(struct vm_fault *vmf)
      else
          prot = vm_get_page_prot(vma->vm_flags);
  -    ret = ttm_bo_vm_fault_reserved(vmf, prot, num_prefault, 1);
+    ret = ttm_bo_vm_fault_reserved(bo, vmf,
+ drm_vma_node_start(&bo->base.vma_node),
+                       prot, num_prefault, 1);
      if (ret == VM_FAULT_RETRY && !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) 
          return ret;
  @@ -546,7 +548,9 @@ vm_fault_t vmw_bo_vm_huge_fault(struct vm_fault *vmf, 
          prot = vm_get_page_prot(vma->vm_flags);
      }
  -    ret = ttm_bo_vm_fault_reserved(vmf, prot, 1, fault_page_size);
+    ret = ttm_bo_vm_fault_reserved(bo, vmf,
+ drm_vma_node_start(&bo->base.vma_node),
+                       prot, 1, fault_page_size);
      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 639521880c29..434f91f1fdbf 100644
--- a/include/drm/ttm/ttm_bo_api.h
+++ b/include/drm/ttm/ttm_bo_api.h
@@ -605,7 +605,9 @@ int ttm_mem_evict_first(struct ttm_device *bdev,
  vm_fault_t ttm_bo_vm_reserve(struct ttm_buffer_object *bo,
                   struct vm_fault *vmf);
  -vm_fault_t ttm_bo_vm_fault_reserved(struct vm_fault *vmf,
+vm_fault_t ttm_bo_vm_fault_reserved(struct ttm_buffer_object *bo,
+                    struct vm_fault *vmf,
+                    unsigned long mmap_base,
                      pgprot_t prot,
                      pgoff_t num_prefault,
                      pgoff_t fault_page_size);
@@ -616,6 +618,11 @@ void ttm_bo_vm_open(struct vm_area_struct *vma);
    void ttm_bo_vm_close(struct vm_area_struct *vma);
  +int ttm_bo_vm_access_reserved(struct ttm_buffer_object *bo,
+                  struct vm_area_struct *vma,
+                  unsigned long offset,
+                  void *buf, int len, int write);
+
  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);



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