anv: Don't presume to know what address is in a surface relocation

Because our relocation processing happens at EndCommandBuffer time and
because RENDER_SURFACE_STATE objects may be shared by batches, we really
have no clue whatsoever what address is actually written to the relocation
offset in the BO.  We need to stop making such claims to the kernel and
just let it relocate for us.

Signed-off-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Kristian H. Kristensen <hoegsberg@google.com>
Cc: "13.0" <mesa-stable@lists.freedesktop.org>
(cherry picked from commit ba1eea4f957ca068eceea121bc3a70e2fe07873d)

2 files changed, 15 insertions, 53 deletions

diff --git a/src/intel/vulkan/anv_batch_chain.c b/src/intel/vulkan/anv_batch_chain.c
index 529fe7e..2c0f803 100644
--- a/src/intel/vulkan/anv_batch_chain.c
+++ b/src/intel/vulkan/anv_batch_chain.c
@@ -940,32 +940,8 @@ static void
 anv_cmd_buffer_process_relocs(struct anv_cmd_buffer *cmd_buffer,
                               struct anv_reloc_list *list)
 {
-   struct anv_bo *bo;
-
-   /* If the kernel supports I915_EXEC_NO_RELOC, it will compare offset in
-    * struct drm_i915_gem_exec_object2 against the bos current offset and if
-    * all bos haven't moved it will skip relocation processing alltogether.
-    * If I915_EXEC_NO_RELOC is not supported, the kernel ignores the incoming
-    * value of offset so we can set it either way.  For that to work we need
-    * to make sure all relocs use the same presumed offset.
-    */
-
-   for (size_t i = 0; i < list->num_relocs; i++) {
-      bo = list->reloc_bos[i];
-      if (bo->offset != list->relocs[i].presumed_offset)
-         cmd_buffer->execbuf2.need_reloc = true;
-
-      list->relocs[i].target_handle = bo->index;
-   }
-}
-
-static uint64_t
-read_reloc(const struct anv_device *device, const void *p)
-{
-   if (device->info.gen >= 8)
-      return *(uint64_t *)p;
-   else
-      return *(uint32_t *)p;
+   for (size_t i = 0; i < list->num_relocs; i++)
+      list->relocs[i].target_handle = list->reloc_bos[i]->index;
 }
 
 static void
@@ -978,27 +954,10 @@ write_reloc(const struct anv_device *device, void *p, uint64_t v)
 }
 
 static void
-adjust_relocations_from_block_pool(struct anv_block_pool *pool,
+adjust_relocations_from_state_pool(struct anv_block_pool *pool,
                                    struct anv_reloc_list *relocs)
 {
    for (size_t i = 0; i < relocs->num_relocs; i++) {
-      /* In general, we don't know how stale the relocated value is.  It
-       * may have been used last time or it may not.  Since we don't want
-       * to stomp it while the GPU may be accessing it, we haven't updated
-       * it anywhere else in the code.  Instead, we just set the presumed
-       * offset to what it is now based on the delta and the data in the
-       * block pool.  Then the kernel will update it for us if needed.
-       */
-      assert(relocs->relocs[i].offset < pool->state.end);
-      const void *p = pool->map + relocs->relocs[i].offset;
-
-      /* We're reading back the relocated value from potentially incoherent
-       * memory here. However, any change to the value will be from the kernel
-       * writing out relocations, which will keep the CPU cache up to date.
-       */
-      relocs->relocs[i].presumed_offset =
-         read_reloc(pool->device, p) - relocs->relocs[i].delta;
-
       /* All of the relocations from this block pool to other BO's should
        * have been emitted relative to the surface block pool center.  We
        * need to add the center offset to make them relative to the
@@ -1009,7 +968,7 @@ adjust_relocations_from_block_pool(struct anv_block_pool *pool,
 }
 
 static void
-adjust_relocations_to_block_pool(struct anv_block_pool *pool,
+adjust_relocations_to_state_pool(struct anv_block_pool *pool,
                                  struct anv_bo *from_bo,
                                  struct anv_reloc_list *relocs,
                                  uint32_t *last_pool_center_bo_offset)
@@ -1055,9 +1014,8 @@ anv_cmd_buffer_prepare_execbuf(struct anv_cmd_buffer *cmd_buffer)
       &cmd_buffer->device->surface_state_block_pool;
 
    cmd_buffer->execbuf2.bo_count = 0;
-   cmd_buffer->execbuf2.need_reloc = false;
 
-   adjust_relocations_from_block_pool(ss_pool, &cmd_buffer->surface_relocs);
+   adjust_relocations_from_state_pool(ss_pool, &cmd_buffer->surface_relocs);
    anv_cmd_buffer_add_bo(cmd_buffer, &ss_pool->bo, &cmd_buffer->surface_relocs);
 
    /* First, we walk over all of the bos we've seen and add them and their
@@ -1065,7 +1023,7 @@ anv_cmd_buffer_prepare_execbuf(struct anv_cmd_buffer *cmd_buffer)
     */
    struct anv_batch_bo **bbo;
    u_vector_foreach(bbo, &cmd_buffer->seen_bbos) {
-      adjust_relocations_to_block_pool(ss_pool, &(*bbo)->bo, &(*bbo)->relocs,
+      adjust_relocations_to_state_pool(ss_pool, &(*bbo)->bo, &(*bbo)->relocs,
                                        &(*bbo)->last_ss_pool_bo_offset);
 
       anv_cmd_buffer_add_bo(cmd_buffer, &(*bbo)->bo, &(*bbo)->relocs);
@@ -1127,15 +1085,21 @@ anv_cmd_buffer_prepare_execbuf(struct anv_cmd_buffer *cmd_buffer)
       .rsvd1 = cmd_buffer->device->context_id,
       .rsvd2 = 0,
    };
-
-   if (!cmd_buffer->execbuf2.need_reloc)
-      cmd_buffer->execbuf2.execbuf.flags |= I915_EXEC_NO_RELOC;
 }
 
 VkResult
 anv_cmd_buffer_execbuf(struct anv_device *device,
                        struct anv_cmd_buffer *cmd_buffer)
 {
+   /* Since surface states are shared between command buffers and we don't
+    * know what order they will be submitted to the kernel, we don't know what
+    * address is actually written in the surface state object at any given
+    * time.  The only option is to set a bogus presumed offset and let
+    * relocations do their job.
+    */
+   for (size_t i = 0; i < cmd_buffer->surface_relocs.num_relocs; i++)
+      cmd_buffer->surface_relocs.relocs[i].presumed_offset = -1;
+
    return anv_device_execbuf(device, &cmd_buffer->execbuf2.execbuf,
                              cmd_buffer->execbuf2.bos);
 }
diff --git a/src/intel/vulkan/anv_private.h b/src/intel/vulkan/anv_private.h
index 09345c8..3b17171 100644
--- a/src/intel/vulkan/anv_private.h
+++ b/src/intel/vulkan/anv_private.h
@@ -1173,8 +1173,6 @@ struct anv_cmd_buffer {
 
       /* Allocated length of the 'objects' and 'bos' arrays */
       uint32_t                                  array_length;
-
-      bool                                      need_reloc;
    } execbuf2;
 
    /* Serial for tracking buffer completion */