drm/vmwgfx: Fix prime import/export

vmwgfx never supported prime import of external buffers. Furthermore the
driver exposes two different objects to userspace: vmw_surface's and
gem buffers but prime import/export only worked with vmw_surfaces.

Because gem buffers are used through the dumb_buffer interface this meant
that the driver created buffers couldn't have been prime exported or
imported.

Fix prime import/export. Makes IGT's kms_prime pass.

Signed-off-by: Zack Rusin <zack.rusin@broadcom.com>
Fixes: 8afa13a0583f ("drm/vmwgfx: Implement DRIVER_GEM")
Cc: <stable@vger.kernel.org> # v6.6+
Reviewed-by: Martin Krastev <martin.krastev@broadcom.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240412025511.78553-4-zack.rusin@broadcom.com

1 files changed, 30 insertions, 14 deletions

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c
index 4d23d0a70bcb..621d98b376bb 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_ttm_buffer.c
@@ -188,13 +188,18 @@ static int vmw_ttm_map_dma(struct vmw_ttm_tt *vmw_tt)
 	switch (dev_priv->map_mode) {
 	case vmw_dma_map_bind:
 	case vmw_dma_map_populate:
-		vsgt->sgt = &vmw_tt->sgt;
-		ret = sg_alloc_table_from_pages_segment(
-			&vmw_tt->sgt, vsgt->pages, vsgt->num_pages, 0,
-			(unsigned long)vsgt->num_pages << PAGE_SHIFT,
-			dma_get_max_seg_size(dev_priv->drm.dev), GFP_KERNEL);
-		if (ret)
-			goto out_sg_alloc_fail;
+		if (vmw_tt->dma_ttm.page_flags  & TTM_TT_FLAG_EXTERNAL) {
+			vsgt->sgt = vmw_tt->dma_ttm.sg;
+		} else {
+			vsgt->sgt = &vmw_tt->sgt;
+			ret = sg_alloc_table_from_pages_segment(&vmw_tt->sgt,
+				vsgt->pages, vsgt->num_pages, 0,
+				(unsigned long)vsgt->num_pages << PAGE_SHIFT,
+				dma_get_max_seg_size(dev_priv->drm.dev),
+				GFP_KERNEL);
+			if (ret)
+				goto out_sg_alloc_fail;
+		}
 
 		ret = vmw_ttm_map_for_dma(vmw_tt);
 		if (unlikely(ret != 0))
@@ -209,8 +214,9 @@ static int vmw_ttm_map_dma(struct vmw_ttm_tt *vmw_tt)
 	return 0;
 
 out_map_fail:
-	sg_free_table(vmw_tt->vsgt.sgt);
-	vmw_tt->vsgt.sgt = NULL;
+	drm_warn(&dev_priv->drm, "VSG table map failed!");
+	sg_free_table(vsgt->sgt);
+	vsgt->sgt = NULL;
 out_sg_alloc_fail:
 	return ret;
 }
@@ -356,15 +362,17 @@ static void vmw_ttm_destroy(struct ttm_device *bdev, struct ttm_tt *ttm)
 static int vmw_ttm_populate(struct ttm_device *bdev,
 			    struct ttm_tt *ttm, struct ttm_operation_ctx *ctx)
 {
-	int ret;
+	bool external = (ttm->page_flags & TTM_TT_FLAG_EXTERNAL) != 0;
 
-	/* TODO: maybe completely drop this ? */
 	if (ttm_tt_is_populated(ttm))
 		return 0;
 
-	ret = ttm_pool_alloc(&bdev->pool, ttm, ctx);
+	if (external && ttm->sg)
+		return  drm_prime_sg_to_dma_addr_array(ttm->sg,
+						       ttm->dma_address,
+						       ttm->num_pages);
 
-	return ret;
+	return ttm_pool_alloc(&bdev->pool, ttm, ctx);
 }
 
 static void vmw_ttm_unpopulate(struct ttm_device *bdev,
@@ -372,6 +380,10 @@ static void vmw_ttm_unpopulate(struct ttm_device *bdev,
 {
 	struct vmw_ttm_tt *vmw_tt = container_of(ttm, struct vmw_ttm_tt,
 						 dma_ttm);
+	bool external = (ttm->page_flags & TTM_TT_FLAG_EXTERNAL) != 0;
+
+	if (external)
+		return;
 
 	vmw_ttm_unbind(bdev, ttm);
 
@@ -390,6 +402,7 @@ static struct ttm_tt *vmw_ttm_tt_create(struct ttm_buffer_object *bo,
 {
 	struct vmw_ttm_tt *vmw_be;
 	int ret;
+	bool external = bo->type == ttm_bo_type_sg;
 
 	vmw_be = kzalloc(sizeof(*vmw_be), GFP_KERNEL);
 	if (!vmw_be)
@@ -398,7 +411,10 @@ static struct ttm_tt *vmw_ttm_tt_create(struct ttm_buffer_object *bo,
 	vmw_be->dev_priv = vmw_priv_from_ttm(bo->bdev);
 	vmw_be->mob = NULL;
 
-	if (vmw_be->dev_priv->map_mode == vmw_dma_alloc_coherent)
+	if (external)
+		page_flags |= TTM_TT_FLAG_EXTERNAL | TTM_TT_FLAG_EXTERNAL_MAPPABLE;
+
+	if (vmw_be->dev_priv->map_mode == vmw_dma_alloc_coherent || external)
 		ret = ttm_sg_tt_init(&vmw_be->dma_ttm, bo, page_flags,
 				     ttm_cached);
 	else