Implement virtgpu specific map_dma_buf callback to support mapping
exported vram object dma-bufs. The dma-buf callback is used directly, as
vram objects don't have backing pages and thus can't implement the
drm_gem_object_funcs.get_sg_table callback.
Signed-off-by: David Stevens <steve...@chromium.org>
---
v1 -> v2:
- reflow line to fix strict checkpatch warning
- replace else with return for consistency between functions
---
drivers/gpu/drm/virtio/virtgpu_drv.h | 8 ++++
drivers/gpu/drm/virtio/virtgpu_prime.c | 32 +++++++++++++-
drivers/gpu/drm/virtio/virtgpu_vram.c | 61 ++++++++++++++++++++++++++
3 files changed, 99 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h
b/drivers/gpu/drm/virtio/virtgpu_drv.h
index d4e610a44e12..0c4810982530 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -26,6 +26,7 @@
#ifndef VIRTIO_DRV_H
#define VIRTIO_DRV_H
+#include <linux/dma-direction.h>
#include <linux/virtio.h>
#include <linux/virtio_ids.h>
#include <linux/virtio_config.h>
@@ -459,4 +460,11 @@ bool virtio_gpu_is_vram(struct virtio_gpu_object *bo);
int virtio_gpu_vram_create(struct virtio_gpu_device *vgdev,
struct virtio_gpu_object_params *params,
struct virtio_gpu_object **bo_ptr);
+struct sg_table *virtio_gpu_vram_map_dma_buf(struct virtio_gpu_object *bo,
+ struct device *dev,
+ enum dma_data_direction dir);
+void virtio_gpu_vram_unmap_dma_buf(struct device *dev,
+ struct sg_table *sgt,
+ enum dma_data_direction dir);
+
#endif
diff --git a/drivers/gpu/drm/virtio/virtgpu_prime.c
b/drivers/gpu/drm/virtio/virtgpu_prime.c
index 807a27a16365..7b940be3323f 100644
--- a/drivers/gpu/drm/virtio/virtgpu_prime.c
+++ b/drivers/gpu/drm/virtio/virtgpu_prime.c
@@ -43,13 +43,41 @@ static int virtgpu_virtio_get_uuid(struct dma_buf *buf,
return 0;
}
+static struct sg_table *
+virtgpu_gem_map_dma_buf(struct dma_buf_attachment *attach,
+ enum dma_data_direction dir)
+{
+ struct drm_gem_object *obj = attach->dmabuf->priv;
+ struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
+
+ if (virtio_gpu_is_vram(bo))
+ return virtio_gpu_vram_map_dma_buf(bo, attach->dev, dir);
+
+ return drm_gem_map_dma_buf(attach, dir);
+}
+
+static void virtgpu_gem_unmap_dma_buf(struct dma_buf_attachment *attach,
+ struct sg_table *sgt,
+ enum dma_data_direction dir)
+{
+ struct drm_gem_object *obj = attach->dmabuf->priv;
+ struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
+
+ if (virtio_gpu_is_vram(bo)) {
+ virtio_gpu_vram_unmap_dma_buf(attach->dev, sgt, dir);
+ return;
+ }
+
+ drm_gem_unmap_dma_buf(attach, sgt, dir);
+}
+
static const struct virtio_dma_buf_ops virtgpu_dmabuf_ops = {
.ops = {
.cache_sgt_mapping = true,
.attach = virtio_dma_buf_attach,
.detach = drm_gem_map_detach,
- .map_dma_buf = drm_gem_map_dma_buf,
- .unmap_dma_buf = drm_gem_unmap_dma_buf,
+ .map_dma_buf = virtgpu_gem_map_dma_buf,
+ .unmap_dma_buf = virtgpu_gem_unmap_dma_buf,
.release = drm_gem_dmabuf_release,
.mmap = drm_gem_dmabuf_mmap,
.vmap = drm_gem_dmabuf_vmap,
diff --git a/drivers/gpu/drm/virtio/virtgpu_vram.c
b/drivers/gpu/drm/virtio/virtgpu_vram.c
index 5cc34e7330fa..6b45b0429fef 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vram.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vram.c
@@ -1,6 +1,8 @@
// SPDX-License-Identifier: GPL-2.0
#include "virtgpu_drv.h"
+#include <linux/dma-mapping.h>
+
static void virtio_gpu_vram_free(struct drm_gem_object *obj)
{
struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj);
@@ -64,6 +66,65 @@ static int virtio_gpu_vram_mmap(struct drm_gem_object *obj,
return ret;
}
+struct sg_table *virtio_gpu_vram_map_dma_buf(struct virtio_gpu_object *bo,
+ struct device *dev,
+ enum dma_data_direction dir)
+{
+ struct virtio_gpu_device *vgdev = bo->base.base.dev->dev_private;
+ struct virtio_gpu_object_vram *vram = to_virtio_gpu_vram(bo);
+ struct sg_table *sgt;
+ dma_addr_t addr;
+ int ret;
+
+ sgt = kzalloc(sizeof(*sgt), GFP_KERNEL);
+ if (!sgt)
+ return ERR_PTR(-ENOMEM);
+
+ if (!(bo->blob_flags & VIRTGPU_BLOB_FLAG_USE_MAPPABLE)) {
+ // Virtio devices can access the dma-buf via its UUID. Return a
stub
+ // sg_table so the dma-buf API still works.
+ if (!is_virtio_device(dev) || !vgdev->has_resource_assign_uuid)
{
+ ret = -EIO;
+ goto out;
+ }
+ return sgt;
+ }
+
+ ret = sg_alloc_table(sgt, 1, GFP_KERNEL);
+ if (ret)
+ goto out;
+
+ addr = dma_map_resource(dev, vram->vram_node.start,
+ vram->vram_node.size, dir,
+ DMA_ATTR_SKIP_CPU_SYNC);
+ ret = dma_mapping_error(dev, addr);
+ if (ret)
+ goto out;
+
+ sg_set_page(sgt->sgl, NULL, vram->vram_node.size, 0);
+ sg_dma_address(sgt->sgl) = addr;
+ sg_dma_len(sgt->sgl) = vram->vram_node.size;
+
+ return sgt;
+out:
+ sg_free_table(sgt);
+ kfree(sgt);
+ return ERR_PTR(ret);
+}
+
+void virtio_gpu_vram_unmap_dma_buf(struct device *dev,
+ struct sg_table *sgt,
+ enum dma_data_direction dir)
+{
+ if (sgt->nents) {
+ dma_unmap_resource(dev, sg_dma_address(sgt->sgl),
+ sg_dma_len(sgt->sgl), dir,
+ DMA_ATTR_SKIP_CPU_SYNC);
+ }
+ sg_free_table(sgt);
+ kfree(sgt);
+}
+
static const struct drm_gem_object_funcs virtio_gpu_vram_funcs = {
.open = virtio_gpu_gem_object_open,
.close = virtio_gpu_gem_object_close,
--
2.33.0.rc1.237.g0d66db33f3-goog
