On 5/1/26 03:00, Dmitry Osipenko wrote: > If userspace never maps GEM object, then BO wastes hostmem space > because VirtIO-GPU driver maps VRAM BO at the BO's creating time. > > Make mappings on-demand by adding new RESOURCE_CREATE_BLOB IOCTL/UAPI > hinting flag telling that host mapping should be deferred until first > mapping is made when the flag is set by userspace. > > Signed-off-by: Dmitry Osipenko <[email protected]> > Reviewed-by: Rob Clark <[email protected]> > --- > > Changelog: > > v2: Rebased on recent kernel. Intel i915 native ctx landed to Mesa, lets to > proceed with merging the mapping hint as a first user of the feature. > > drivers/gpu/drm/virtio/virtgpu_drv.h | 2 ++ > drivers/gpu/drm/virtio/virtgpu_ioctl.c | 1 + > drivers/gpu/drm/virtio/virtgpu_vram.c | 30 +++++++++++++++++++++----- > include/uapi/drm/virtgpu_drm.h | 4 ++++ > 4 files changed, 32 insertions(+), 5 deletions(-) > > diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h > b/drivers/gpu/drm/virtio/virtgpu_drv.h > index f17660a71a3e..6f49213e23f8 100644 > --- a/drivers/gpu/drm/virtio/virtgpu_drv.h > +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h > @@ -84,6 +84,7 @@ struct virtio_gpu_object_params { > uint32_t blob_mem; > uint32_t blob_flags; > uint64_t blob_id; > + uint32_t blob_hints; > }; > > struct virtio_gpu_object { > @@ -507,6 +508,7 @@ struct sg_table *virtio_gpu_vram_map_dma_buf(struct > virtio_gpu_object *bo, > void virtio_gpu_vram_unmap_dma_buf(struct device *dev, > struct sg_table *sgt, > enum dma_data_direction dir); > +void virtio_gpu_vram_map_deferred(struct virtio_gpu_object_vram *vram); > > /* virtgpu_submit.c */ > int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data, > diff --git a/drivers/gpu/drm/virtio/virtgpu_ioctl.c > b/drivers/gpu/drm/virtio/virtgpu_ioctl.c > index c33c057365f8..01daa72b1310 100644 > --- a/drivers/gpu/drm/virtio/virtgpu_ioctl.c > +++ b/drivers/gpu/drm/virtio/virtgpu_ioctl.c > @@ -489,6 +489,7 @@ static int verify_blob(struct virtio_gpu_device *vgdev, > params->size = rc_blob->size; > params->blob = true; > params->blob_flags = rc_blob->blob_flags; > + params->blob_hints = rc_blob->blob_hints; > return 0; > } > > diff --git a/drivers/gpu/drm/virtio/virtgpu_vram.c > b/drivers/gpu/drm/virtio/virtgpu_vram.c > index 084e80227433..4ae3cbc35dd3 100644 > --- a/drivers/gpu/drm/virtio/virtgpu_vram.c > +++ b/drivers/gpu/drm/virtio/virtgpu_vram.c > @@ -3,6 +3,8 @@ > > #include <linux/dma-mapping.h> > > +static DEFINE_MUTEX(map_lock); > + > static void virtio_gpu_vram_free(struct drm_gem_object *obj) > { > struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj); > @@ -42,6 +44,11 @@ static int virtio_gpu_vram_mmap(struct drm_gem_object *obj, > if (!(bo->blob_flags & VIRTGPU_BLOB_FLAG_USE_MAPPABLE)) > return -EINVAL; > > + virtio_gpu_vram_map_deferred(vram); > + > + if (vram->map_state == STATE_INITIALIZING) > + virtio_gpu_notify(vgdev); > + > wait_event(vgdev->resp_wq, vram->map_state != STATE_INITIALIZING); > if (vram->map_state != STATE_OK) > return -EINVAL; > @@ -218,14 +225,27 @@ int virtio_gpu_vram_create(struct virtio_gpu_device > *vgdev, > > virtio_gpu_cmd_resource_create_blob(vgdev, &vram->base, params, NULL, > 0); > - if (params->blob_flags & VIRTGPU_BLOB_FLAG_USE_MAPPABLE) { > - ret = virtio_gpu_vram_map(&vram->base); > - if (ret) { > - virtio_gpu_vram_free(obj); > - return ret; > + if (!(params->blob_hints & DRM_VIRTGPU_BLOB_FLAG_HINT_DEFER_MAPPING)) { > + if (params->blob_flags & VIRTGPU_BLOB_FLAG_USE_MAPPABLE) { > + ret = virtio_gpu_vram_map(&vram->base); > + if (ret) { > + virtio_gpu_vram_free(obj); > + return ret; > + } > } > } > > *bo_ptr = &vram->base; > return 0; > } > + > +void virtio_gpu_vram_map_deferred(struct virtio_gpu_object_vram *vram) > +{ > + if (!(vram->base.blob_flags & VIRTGPU_BLOB_FLAG_USE_MAPPABLE)) > + return; > + > + mutex_lock(&map_lock); > + if (!drm_mm_node_allocated(&vram->vram_node)) > + virtio_gpu_vram_map(&vram->base); > + mutex_unlock(&map_lock); > +} > diff --git a/include/uapi/drm/virtgpu_drm.h b/include/uapi/drm/virtgpu_drm.h > index 9debb320c34b..ba09a4ee3e77 100644 > --- a/include/uapi/drm/virtgpu_drm.h > +++ b/include/uapi/drm/virtgpu_drm.h > @@ -200,6 +200,10 @@ struct drm_virtgpu_resource_create_blob { > __u32 cmd_size; > __u64 cmd; > __u64 blob_id; > + > +#define DRM_VIRTGPU_BLOB_FLAG_HINT_DEFER_MAPPING 0x0001 > + __u32 blob_hints; > + __u32 pad2; > }; > > #define VIRTGPU_CONTEXT_PARAM_CAPSET_ID 0x0001
Applied patch to misc-next -- Best regards, Dmitry
