From 543bcfd95673805028b7589a44a361758c9ea044 Mon Sep 17 00:00:00 2001
From: jsg <jsg@openbsd.org>
Date: Fri, 22 Jul 2022 06:16:07 +0000
Subject: [PATCH] drm/i915: Require the vm mutex for i915_vma_bind()

From Thomas Hellstrom
a6cecaf058c48c6def2548473d814a2d54cb3667 in linux 5.15.y/5.15.56
c2ea703dcafccf18d7d77d8b68fb08c2d9842b7a in mainline linux
---
 .../pci/drm/i915/gem/i915_gem_execbuffer.c    | 60 ++++++++++++++++++-
 sys/dev/pci/drm/i915/i915_vma.c               |  1 +
 2 files changed, 60 insertions(+), 1 deletion(-)

diff --git a/sys/dev/pci/drm/i915/gem/i915_gem_execbuffer.c b/sys/dev/pci/drm/i915/gem/i915_gem_execbuffer.c
index 69cf1d2bbdf..d592c6e361b 100644
--- a/sys/dev/pci/drm/i915/gem/i915_gem_execbuffer.c
+++ b/sys/dev/pci/drm/i915/gem/i915_gem_execbuffer.c
@@ -1070,6 +1070,57 @@ static inline struct i915_ggtt *cache_to_ggtt(struct reloc_cache *cache)
 	return &i915->ggtt;
 }
 
+static void reloc_cache_unmap(struct reloc_cache *cache)
+{
+	void *vaddr;
+
+	if (!cache->vaddr)
+		return;
+
+	vaddr = unmask_page(cache->vaddr);
+	if (cache->vaddr & KMAP)
+		kunmap_atomic(vaddr);
+	else
+#ifdef __linux__
+		io_mapping_unmap_atomic((void __iomem *)vaddr);
+#else
+		agp_unmap_atomic(cache->map, cache->ioh);
+#endif
+}
+
+static void reloc_cache_remap(struct reloc_cache *cache,
+			      struct drm_i915_gem_object *obj)
+{
+	void *vaddr;
+
+	if (!cache->vaddr)
+		return;
+
+	if (cache->vaddr & KMAP) {
+		struct vm_page *page = i915_gem_object_get_page(obj, cache->page);
+
+		vaddr = kmap_atomic(page);
+		cache->vaddr = unmask_flags(cache->vaddr) |
+			(unsigned long)vaddr;
+	} else {
+		struct i915_ggtt *ggtt = cache_to_ggtt(cache);
+		unsigned long offset;
+
+		offset = cache->node.start;
+		if (!drm_mm_node_allocated(&cache->node))
+			offset += cache->page << PAGE_SHIFT;
+
+#ifdef __linux__
+		cache->vaddr = (unsigned long)
+			io_mapping_map_atomic_wc(&ggtt->iomap, offset);
+#else
+		agp_map_atomic(cache->map, offset, &cache->ioh);
+		cache->vaddr = (unsigned long)
+			bus_space_vaddr(cache->iot, cache->ioh);
+#endif
+	}
+}
+
 static void reloc_cache_reset(struct reloc_cache *cache, struct i915_execbuffer *eb)
 {
 	void *vaddr;
@@ -1347,10 +1398,17 @@ eb_relocate_entry(struct i915_execbuffer *eb,
 		 * batchbuffers.
 		 */
 		if (reloc->write_domain == I915_GEM_DOMAIN_INSTRUCTION &&
-		    GRAPHICS_VER(eb->i915) == 6) {
+		    GRAPHICS_VER(eb->i915) == 6 &&
+		    !i915_vma_is_bound(target->vma, I915_VMA_GLOBAL_BIND)) {
+			struct i915_vma *vma = target->vma;
+
+			reloc_cache_unmap(&eb->reloc_cache);
+			mutex_lock(&vma->vm->mutex);
 			err = i915_vma_bind(target->vma,
 					    target->vma->obj->cache_level,
 					    PIN_GLOBAL, NULL);
+			mutex_unlock(&vma->vm->mutex);
+			reloc_cache_remap(&eb->reloc_cache, ev->vma->obj);
 			if (err)
 				return err;
 		}
diff --git a/sys/dev/pci/drm/i915/i915_vma.c b/sys/dev/pci/drm/i915/i915_vma.c
index 8a20291f385..29c7414e3da 100644
--- a/sys/dev/pci/drm/i915/i915_vma.c
+++ b/sys/dev/pci/drm/i915/i915_vma.c
@@ -388,6 +388,7 @@ int i915_vma_bind(struct i915_vma *vma,
 	u32 bind_flags;
 	u32 vma_flags;
 
+	lockdep_assert_held(&vma->vm->mutex);
 	GEM_BUG_ON(!drm_mm_node_allocated(&vma->node));
 	GEM_BUG_ON(vma->size > vma->node.size);
 
-- 
2.20.1