From ca77f27a26657098702a25371d8b90e6004e2773 Mon Sep 17 00:00:00 2001 From: Vivek Kasireddy Date: Mon, 25 Nov 2024 19:13:45 -0800 Subject: [PATCH] drm/virtio: Import prime buffers from other devices as guest blobs By importing scanout buffers from other devices, we should be able to use the virtio-gpu driver in KMS only mode. Note that we attach dynamically and register a move_notify() callback so that we can let the VMM know of any location changes associated with the backing store of the imported object by sending detach_backing cmd. Cc: Gerd Hoffmann Cc: Dmitry Osipenko Cc: Rob Clark Cc: Gurchetan Singh Cc: Chia-I Wu Signed-off-by: Vivek Kasireddy Tested-by: Dmitry Osipenko Reviewed-by: Dmitry Osipenko Signed-off-by: Dmitry Osipenko [dmitry.osipenko@collabora.com: added kref check to move_notify] Link: https://patchwork.freedesktop.org/patch/msgid/20241126031643.3490496-5-vivek.kasireddy@intel.com --- drivers/gpu/drm/virtio/virtgpu_prime.c | 65 ++++++++++++++++++++++++-- 1 file changed, 62 insertions(+), 3 deletions(-) diff --git a/drivers/gpu/drm/virtio/virtgpu_prime.c b/drivers/gpu/drm/virtio/virtgpu_prime.c index 887b635dec6fcf..688810d1b61124 100644 --- a/drivers/gpu/drm/virtio/virtgpu_prime.c +++ b/drivers/gpu/drm/virtio/virtgpu_prime.c @@ -189,13 +189,18 @@ static void virtgpu_dma_buf_free_obj(struct drm_gem_object *obj) struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj); struct virtio_gpu_device *vgdev = obj->dev->dev_private; struct dma_buf_attachment *attach = obj->import_attach; + struct dma_resv *resv = attach->dmabuf->resv; if (attach) { + dma_resv_lock(resv, NULL); + virtio_gpu_detach_object_fenced(bo); if (bo->sgt) - dma_buf_unmap_attachment_unlocked(attach, bo->sgt, - DMA_BIDIRECTIONAL); + dma_buf_unmap_attachment(attach, bo->sgt, + DMA_BIDIRECTIONAL); + + dma_resv_unlock(resv); dma_buf_detach(attach->dmabuf, attach); dma_buf_put(attach->dmabuf); @@ -259,10 +264,39 @@ static int virtgpu_dma_buf_init_obj(struct drm_device *dev, return ret; } +static const struct drm_gem_object_funcs virtgpu_gem_dma_buf_funcs = { + .free = virtgpu_dma_buf_free_obj, +}; + +static void virtgpu_dma_buf_move_notify(struct dma_buf_attachment *attach) +{ + struct drm_gem_object *obj = attach->importer_priv; + struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj); + + if (bo->created && kref_read(&obj->refcount)) { + virtio_gpu_detach_object_fenced(bo); + + if (bo->sgt) + dma_buf_unmap_attachment(attach, bo->sgt, + DMA_BIDIRECTIONAL); + + bo->sgt = NULL; + } +} + +static const struct dma_buf_attach_ops virtgpu_dma_buf_attach_ops = { + .allow_peer2peer = true, + .move_notify = virtgpu_dma_buf_move_notify +}; + struct drm_gem_object *virtgpu_gem_prime_import(struct drm_device *dev, struct dma_buf *buf) { + struct virtio_gpu_device *vgdev = dev->dev_private; + struct dma_buf_attachment *attach; + struct virtio_gpu_object *bo; struct drm_gem_object *obj; + int ret; if (buf->ops == &virtgpu_dmabuf_ops.ops) { obj = buf->priv; @@ -276,7 +310,32 @@ struct drm_gem_object *virtgpu_gem_prime_import(struct drm_device *dev, } } - return drm_gem_prime_import(dev, buf); + if (!vgdev->has_resource_blob || vgdev->has_virgl_3d) + return drm_gem_prime_import(dev, buf); + + bo = kzalloc(sizeof(*bo), GFP_KERNEL); + if (!bo) + return ERR_PTR(-ENOMEM); + + obj = &bo->base.base; + obj->funcs = &virtgpu_gem_dma_buf_funcs; + drm_gem_private_object_init(dev, obj, buf->size); + + attach = dma_buf_dynamic_attach(buf, dev->dev, + &virtgpu_dma_buf_attach_ops, obj); + if (IS_ERR(attach)) { + kfree(bo); + return ERR_CAST(attach); + } + + obj->import_attach = attach; + get_dma_buf(buf); + + ret = virtgpu_dma_buf_init_obj(dev, bo, attach); + if (ret < 0) + return ERR_PTR(ret); + + return obj; } struct drm_gem_object *virtgpu_gem_prime_import_sg_table(