[PATCH 2/2] drm/i915/gem: Migrate to system at dma-buf map time

[Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>]

Until we support p2p dma or as a complement to that, migrate data
to system memory at dma-buf map time if possible.

v2:
- Rebase on dynamic exporter. Update the igt_dmabuf_import_same_driver
  selftest to migrate if we are LMEM capable.
v3:
- Migrate also in the pin() callback.

Signed-off-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
Reviewed-by: Michael J. Ruhl <michael.j.ruhl@xxxxxxxxx>
---
 drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c    | 21 +++++++++++++++++--
 .../drm/i915/gem/selftests/i915_gem_dmabuf.c  |  4 +++-
 2 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
index 918c19df7b66..13312d89c2ed 100644
--- a/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c
@@ -34,7 +34,14 @@ static struct sg_table *i915_gem_map_dma_buf(struct dma_buf_attachment *attachme
 	 * Let's pin it here to avoid having to call the move_notify
 	 * callback, The call of which is not yet implemented.
 	 */
-	ret = i915_gem_object_pin_pages(obj);
+	if (!i915_gem_object_can_migrate(obj, INTEL_REGION_SMEM))
+		return ERR_PTR(-EOPNOTSUPP);
+
+	ret = i915_gem_object_migrate(obj, NULL, INTEL_REGION_SMEM);
+	if (!ret)
+		ret = i915_gem_object_wait_migration(obj, 0);
+	if (!ret)
+		ret = i915_gem_object_pin_pages(obj);
 	if (ret)
 		goto err;
 
@@ -180,9 +187,19 @@ static int i915_gem_end_cpu_access(struct dma_buf *dma_buf, enum dma_data_direct
 static int i915_gem_dmabuf_pin(struct dma_buf_attachment *attach)
 {
 	struct drm_i915_gem_object *obj = dma_buf_to_obj(attach->dmabuf);
+	int ret;
 
 	assert_object_held(obj);
-	return i915_gem_object_pin_pages(obj);
+
+	if (!i915_gem_object_can_migrate(obj, INTEL_REGION_SMEM))
+		return -EOPNOTSUPP;
+	ret = i915_gem_object_migrate(obj, NULL, INTEL_REGION_SMEM);
+	if (!ret)
+		ret = i915_gem_object_wait_migration(obj, 0);
+	if (!ret)
+		ret = i915_gem_object_pin_pages(obj);
+
+	return ret;
 }
 
 static void i915_gem_dmabuf_unpin(struct dma_buf_attachment *attach)
diff --git a/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c b/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c
index 868b3469ecbd..b1e87ec08741 100644
--- a/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c
+++ b/drivers/gpu/drm/i915/gem/selftests/i915_gem_dmabuf.c
@@ -106,7 +106,9 @@ static int igt_dmabuf_import_same_driver(void *arg)
 	int err;
 
 	force_different_devices = true;
-	obj = i915_gem_object_create_shmem(i915, PAGE_SIZE);
+	obj = i915_gem_object_create_lmem(i915, PAGE_SIZE, 0);
+	if (IS_ERR(obj))
+		obj = i915_gem_object_create_shmem(i915, PAGE_SIZE);
 	if (IS_ERR(obj))
 		goto out_ret;
 
-- 
2.31.1