drm/virtio: add iommu support.

Use the dma mapping api and properly add iommu mappings for
objects, unless virtio is in iommu quirk mode.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Dave Airlie <airlied@redhat.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20180829122026.27012-3-kraxel@redhat.com

2 files changed, 38 insertions, 9 deletions

diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h
index 4fda0da6d949..f8f4a40dd1b8 100644
--- a/drivers/gpu/drm/virtio/virtgpu_drv.h
+++ b/drivers/gpu/drm/virtio/virtgpu_drv.h
@@ -57,6 +57,7 @@ struct virtio_gpu_object {
         uint32_t hw_res_handle;
 
         struct sg_table *pages;
+        uint32_t mapped;
         void *vmap;
         bool dumb;
         struct ttm_place                placement_code;
diff --git a/drivers/gpu/drm/virtio/virtgpu_vq.c b/drivers/gpu/drm/virtio/virtgpu_vq.c
index e23c1927722f..5784c3ea8767 100644
--- a/drivers/gpu/drm/virtio/virtgpu_vq.c
+++ b/drivers/gpu/drm/virtio/virtgpu_vq.c
@@ -424,7 +424,8 @@ void virtio_gpu_cmd_unref_resource(struct virtio_gpu_device *vgdev,
 }
 
 static void virtio_gpu_cmd_resource_inval_backing(struct virtio_gpu_device *vgdev,
-                                                  uint32_t resource_id)
+                                                  uint32_t resource_id,
+                                                  struct virtio_gpu_fence **fence)
 {
         struct virtio_gpu_resource_detach_backing *cmd_p;
         struct virtio_gpu_vbuffer *vbuf;
@@ -435,7 +436,7 @@ static void virtio_gpu_cmd_resource_inval_backing(struct virtio_gpu_device *vgde
         cmd_p->hdr.type = cpu_to_le32(VIRTIO_GPU_CMD_RESOURCE_DETACH_BACKING);
         cmd_p->resource_id = cpu_to_le32(resource_id);
 
-        virtio_gpu_queue_ctrl_buffer(vgdev, vbuf);
+        virtio_gpu_queue_fenced_ctrl_buffer(vgdev, vbuf, &cmd_p->hdr, fence);
 }
 
 void virtio_gpu_cmd_set_scanout(struct virtio_gpu_device *vgdev,
@@ -849,9 +850,10 @@ int virtio_gpu_object_attach(struct virtio_gpu_device *vgdev,
                              uint32_t resource_id,
                              struct virtio_gpu_fence **fence)
 {
+        bool use_dma_api = !virtio_has_iommu_quirk(vgdev->vdev);
         struct virtio_gpu_mem_entry *ents;
         struct scatterlist *sg;
-        int si;
+        int si, nents;
 
         if (!obj->pages) {
                 int ret;
@@ -861,23 +863,33 @@ int virtio_gpu_object_attach(struct virtio_gpu_device *vgdev,
                         return ret;
         }
 
+        if (use_dma_api) {
+                obj->mapped = dma_map_sg(vgdev->vdev->dev.parent,
+                                         obj->pages->sgl, obj->pages->nents,
+                                         DMA_TO_DEVICE);
+                nents = obj->mapped;
+        } else {
+                nents = obj->pages->nents;
+        }
+
         /* gets freed when the ring has consumed it */
-        ents = kmalloc_array(obj->pages->nents,
-                             sizeof(struct virtio_gpu_mem_entry),
+        ents = kmalloc_array(nents, sizeof(struct virtio_gpu_mem_entry),
                              GFP_KERNEL);
         if (!ents) {
                 DRM_ERROR("failed to allocate ent list\n");
                 return -ENOMEM;
         }
 
-        for_each_sg(obj->pages->sgl, sg, obj->pages->nents, si) {
-                ents[si].addr = cpu_to_le64(sg_phys(sg));
+        for_each_sg(obj->pages->sgl, sg, nents, si) {
+                ents[si].addr = cpu_to_le64(use_dma_api
+                                            ? sg_dma_address(sg)
+                                            : sg_phys(sg));
                 ents[si].length = cpu_to_le32(sg->length);
                 ents[si].padding = 0;
         }
 
         virtio_gpu_cmd_resource_attach_backing(vgdev, resource_id,
-                                               ents, obj->pages->nents,
+                                               ents, nents,
                                                fence);
         obj->hw_res_handle = resource_id;
         return 0;
@@ -886,7 +898,23 @@ int virtio_gpu_object_attach(struct virtio_gpu_device *vgdev,
 void virtio_gpu_object_detach(struct virtio_gpu_device *vgdev,
                               struct virtio_gpu_object *obj)
 {
-        virtio_gpu_cmd_resource_inval_backing(vgdev, obj->hw_res_handle);
+        bool use_dma_api = !virtio_has_iommu_quirk(vgdev->vdev);
+        struct virtio_gpu_fence *fence;
+
+        if (use_dma_api && obj->mapped) {
+                /* detach backing and wait for the host process it ... */
+                virtio_gpu_cmd_resource_inval_backing(vgdev, obj->hw_res_handle, &fence);
+                dma_fence_wait(&fence->f, true);
+                dma_fence_put(&fence->f);
+
+                /* ... then tear down iommu mappings */
+                dma_unmap_sg(vgdev->vdev->dev.parent,
+                             obj->pages->sgl, obj->mapped,
+                             DMA_TO_DEVICE);
+                obj->mapped = 0;
+        } else {
+                virtio_gpu_cmd_resource_inval_backing(vgdev, obj->hw_res_handle, NULL);
+        }
 }
 
 void virtio_gpu_cursor_ping(struct virtio_gpu_device *vgdev,