Merge branch 'vmwgfx-coherent' of git://people.freedesktop.org/~thomash/linux into drm-next

Graphics APIs like OpenGL 4.4 and Vulkan require the graphics driver
to provide coherent graphics memory, meaning that the GPU sees any
content written to the coherent memory on the next GPU operation that
touches that memory, and the CPU sees any content written by the GPU
to that memory immediately after any fence object trailing the GPU
operation is signaled.

Paravirtual drivers that otherwise require explicit synchronization
needs to do this by hooking up dirty tracking to pagefault handlers
and buffer object validation.

Provide mm helpers needed for this and that also allow for huge pmd-
and pud entries (patch 1-3), and the associated vmwgfx code (patch 4-7).

The code has been tested and exercised by a tailored version of mesa
where we disable all explicit synchronization and assume graphics memory
is coherent. The performance loss varies of course; a typical number is
around 5%.

Signed-off-by: Dave Airlie <airlied@redhat.com>
From: Thomas Hellstrom <thomas_os@shipmail.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20191113131639.4653-1-thomas_os@shipmail.org

1 files changed, 9 insertions, 0 deletions

diff --git a/include/linux/pagewalk.h b/include/linux/pagewalk.h
index bddd9759bab9..6ec82e92c87f 100644
--- a/include/linux/pagewalk.h
+++ b/include/linux/pagewalk.h
@@ -24,6 +24,9 @@ struct mm_walk;
  *			"do page table walk over the current vma", returning
  *			a negative value means "abort current page table walk
  *			right now" and returning 1 means "skip the current vma"
+ * @pre_vma:            if set, called before starting walk on a non-null vma.
+ * @post_vma:           if set, called after a walk on a non-null vma, provided
+ *                      that @pre_vma and the vma walk succeeded.
  */
 struct mm_walk_ops {
 	int (*pud_entry)(pud_t *pud, unsigned long addr,
@@ -39,6 +42,9 @@ struct mm_walk_ops {
 			     struct mm_walk *walk);
 	int (*test_walk)(unsigned long addr, unsigned long next,
 			struct mm_walk *walk);
+	int (*pre_vma)(unsigned long start, unsigned long end,
+		       struct mm_walk *walk);
+	void (*post_vma)(struct mm_walk *walk);
 };
 
 /**
@@ -62,5 +68,8 @@ int walk_page_range(struct mm_struct *mm, unsigned long start,
 		void *private);
 int walk_page_vma(struct vm_area_struct *vma, const struct mm_walk_ops *ops,
 		void *private);
+int walk_page_mapping(struct address_space *mapping, pgoff_t first_index,
+		      pgoff_t nr, const struct mm_walk_ops *ops,
+		      void *private);
 
 #endif /* _LINUX_PAGEWALK_H */