Add userptr blob objects so the guest kernel can pin an existing userspace mapping and advertise it as CREATE_BLOB backing entries.
- New virtio_gpu_object_userptr type for userptr resources - Pin pages with pin_user_pages_fast() and FOLL_LONGTERM - Charge FOLL_LONGTERM pins against RLIMIT_MEMLOCK - DMA-map the scatterlist only when virtio_gpu_use_dma_api() is required; use DMA_TO_DEVICE for USERPTR_RDONLY - Keep pages pinned until RESOURCE_UNREF is queued; drop them from cleanup_object() on the unref response or on create failure - Clear userptr->pages on pin failure to avoid double-free on cleanup - Reject unaligned or overflowing userptr ranges at create time - Return a fresh SG table from PRIME export Signed-off-by: Honglei Huang <[email protected]> --- drivers/gpu/drm/virtio/Makefile | 3 +- drivers/gpu/drm/virtio/virtgpu_drv.h | 37 +++ drivers/gpu/drm/virtio/virtgpu_object.c | 10 + drivers/gpu/drm/virtio/virtgpu_userptr.c | 335 +++++++++++++++++++++++ 4 files changed, 384 insertions(+), 1 deletion(-) create mode 100644 drivers/gpu/drm/virtio/virtgpu_userptr.c diff --git a/drivers/gpu/drm/virtio/Makefile b/drivers/gpu/drm/virtio/Makefile index d2e1788a82..fe7332a621 100644 --- a/drivers/gpu/drm/virtio/Makefile +++ b/drivers/gpu/drm/virtio/Makefile @@ -6,6 +6,7 @@ virtio-gpu-y := virtgpu_drv.o virtgpu_kms.o virtgpu_gem.o virtgpu_vram.o \ virtgpu_display.o virtgpu_vq.o \ virtgpu_fence.o virtgpu_object.o virtgpu_debugfs.o virtgpu_plane.o \ - virtgpu_ioctl.o virtgpu_prime.o virtgpu_trace_points.o virtgpu_submit.o + virtgpu_ioctl.o virtgpu_prime.o virtgpu_trace_points.o virtgpu_submit.o \ + virtgpu_userptr.o obj-$(CONFIG_DRM_VIRTIO_GPU) += virtio-gpu.o diff --git a/drivers/gpu/drm/virtio/virtgpu_drv.h b/drivers/gpu/drm/virtio/virtgpu_drv.h index 9df4c71173..03791b72ca 100644 --- a/drivers/gpu/drm/virtio/virtgpu_drv.h +++ b/drivers/gpu/drm/virtio/virtgpu_drv.h @@ -105,6 +105,7 @@ struct virtio_gpu_object_params { uint32_t blob_flags; uint64_t blob_id; uint32_t blob_hints; + uint64_t userptr; }; struct virtio_gpu_object { @@ -138,12 +139,42 @@ struct virtio_gpu_object_vram { struct drm_mm_node vram_node; }; +struct virtio_gpu_object_userptr; + +struct virtio_gpu_object_userptr_ops { + int (*get_pages)(struct virtio_gpu_object_userptr *userptr); + void (*put_pages)(struct virtio_gpu_object_userptr *userptr); +}; + +struct virtio_gpu_object_userptr { + struct virtio_gpu_object base; + const struct virtio_gpu_object_userptr_ops *ops; + /* Protects pages and sgt. */ + struct mutex lock; + + uint64_t start; + uint32_t npages; + uint32_t bo_handle; + uint32_t flags; + + struct virtio_gpu_device *vgdev; + struct drm_file *file; + struct page **pages; + struct sg_table *sgt; + bool dma_mapped; + enum dma_data_direction dma_dir; + struct mm_struct *mm; +}; + #define to_virtio_gpu_shmem(virtio_gpu_object) \ container_of((virtio_gpu_object), struct virtio_gpu_object_shmem, base) #define to_virtio_gpu_vram(virtio_gpu_object) \ container_of((virtio_gpu_object), struct virtio_gpu_object_vram, base) +#define to_virtio_gpu_userptr(virtio_gpu_object) \ + container_of((virtio_gpu_object), struct virtio_gpu_object_userptr, base) + struct virtio_gpu_object_array { struct ww_acquire_ctx ticket; struct list_head next; @@ -562,4 +593,10 @@ void virtio_gpu_vram_map_deferred(struct virtio_gpu_object_vram *vram); int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data, struct drm_file *file); +/* virtgpu_userptr.c */ +int virtio_gpu_userptr_create(struct virtio_gpu_device *vgdev, + struct drm_file *file, + struct virtio_gpu_object_params *params, + struct virtio_gpu_object **bo_ptr); +bool virtio_gpu_is_userptr(struct virtio_gpu_object *bo); #endif diff --git a/drivers/gpu/drm/virtio/virtgpu_object.c b/drivers/gpu/drm/virtio/virtgpu_object.c index 49899485be..5c40f5a034 100644 --- a/drivers/gpu/drm/virtio/virtgpu_object.c +++ b/drivers/gpu/drm/virtio/virtgpu_object.c @@ -91,6 +91,16 @@ void virtio_gpu_cleanup_object(struct virtio_gpu_object *bo) drm_gem_free_mmap_offset(&vram->base.base.base); drm_gem_object_release(&vram->base.base.base); kfree(vram); + } else if (virtio_gpu_is_userptr(bo)) { + struct virtio_gpu_object_userptr *userptr = + to_virtio_gpu_userptr(bo); + + mutex_lock(&userptr->lock); + userptr->ops->put_pages(userptr); + mutex_unlock(&userptr->lock); + mutex_destroy(&userptr->lock); + drm_gem_object_release(&userptr->base.base.base); + kfree(userptr); } else { drm_gem_object_release(&bo->base.base); kfree(bo); diff --git a/drivers/gpu/drm/virtio/virtgpu_userptr.c b/drivers/gpu/drm/virtio/virtgpu_userptr.c new file mode 100644 index 0000000000..0097554897 --- /dev/null +++ b/drivers/gpu/drm/virtio/virtgpu_userptr.c @@ -0,0 +1,335 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/dma-mapping.h> +#include <linux/limits.h> +#include <linux/mm.h> +#include <linux/overflow.h> +#include <linux/pid.h> +#include <linux/sched/mm.h> +#include <linux/sched/signal.h> +#include <linux/vmalloc.h> + +#include "virtgpu_drv.h" +#include <drm/drm_gem.h> +#include <drm/drm_prime.h> + +static struct sg_table * +virtio_gpu_userptr_get_sg_table(struct drm_gem_object *obj); + +static void virtio_gpu_userptr_free(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; + + /* + * Keep pages pinned until RESOURCE_UNREF completes. The response + * callback calls virtio_gpu_cleanup_object(), which drops them. + */ + if (bo->created) { + virtio_gpu_remove_from_restore_list(bo); + virtio_gpu_cmd_unref_resource(vgdev, bo, false); + virtio_gpu_notify(vgdev); + return; + } + + virtio_gpu_cleanup_object(bo); +} + +static const struct drm_gem_object_funcs virtio_gpu_userptr_funcs = { + .open = virtio_gpu_gem_object_open, + .close = virtio_gpu_gem_object_close, + .free = virtio_gpu_userptr_free, + .export = virtgpu_gem_prime_export, + .get_sg_table = virtio_gpu_userptr_get_sg_table, +}; + +bool virtio_gpu_is_userptr(struct virtio_gpu_object *bo) +{ + return bo->base.base.funcs == &virtio_gpu_userptr_funcs; +} + +static int +virtio_gpu_userptr_get_pages(struct virtio_gpu_object_userptr *userptr) +{ + unsigned int flag = FOLL_LONGTERM; + unsigned int num_pages, pinned = 0; + int ret = 0; + + if (userptr->pages) + return 0; + + userptr->pages = kvmalloc_array(userptr->npages, sizeof(struct page *), + GFP_KERNEL); + if (!userptr->pages) + return -ENOMEM; + + if (!(userptr->flags & VIRTGPU_BLOB_FLAG_USERPTR_RDONLY)) + flag |= FOLL_WRITE; + + do { + num_pages = userptr->npages - pinned; + + ret = pin_user_pages_fast(userptr->start + pinned * PAGE_SIZE, + num_pages, flag, + userptr->pages + pinned); + + if (ret < 0) { + if (pinned) + unpin_user_pages(userptr->pages, pinned); + kvfree(userptr->pages); + userptr->pages = NULL; + return ret; + } + + pinned += ret; + + } while (pinned < userptr->npages); + + return 0; +} + +static void +virtio_gpu_userptr_unaccount(struct virtio_gpu_object_userptr *userptr) +{ + if (!userptr->mm) + return; + + atomic64_sub(userptr->npages, &userptr->mm->pinned_vm); + mmdrop(userptr->mm); + userptr->mm = NULL; +} + +static void +virtio_gpu_userptr_put_pages(struct virtio_gpu_object_userptr *userptr) +{ + struct drm_device *dev = userptr->base.base.base.dev; + + if (userptr->sgt) { + if (userptr->dma_mapped) + dma_unmap_sgtable(drm_dev_dma_dev(dev), userptr->sgt, + userptr->dma_dir, 0); + userptr->dma_mapped = false; + sg_free_table(userptr->sgt); + kfree(userptr->sgt); + userptr->sgt = NULL; + } + + if (userptr->pages) { + unpin_user_pages(userptr->pages, userptr->npages); + kvfree(userptr->pages); + userptr->pages = NULL; + } + + virtio_gpu_userptr_unaccount(userptr); +} + +static int +virtio_gpu_userptr_get_entries(struct virtio_gpu_device *vgdev, + struct virtio_gpu_object_userptr *userptr, + struct virtio_gpu_mem_entry **ents, + unsigned int *nents) +{ + bool use_dma_api = virtio_gpu_use_dma_api(vgdev->vdev); + struct scatterlist *sg; + unsigned int count; + int si; + + count = use_dma_api ? userptr->sgt->nents : userptr->sgt->orig_nents; + if (!count) + return -EINVAL; + + *ents = kvmalloc_array(count, sizeof(**ents), GFP_KERNEL); + if (!*ents) + return -ENOMEM; + + if (use_dma_api) { + for_each_sgtable_dma_sg(userptr->sgt, sg, si) { + (*ents)[si].addr = cpu_to_le64(sg_dma_address(sg)); + (*ents)[si].length = cpu_to_le32(sg_dma_len(sg)); + (*ents)[si].padding = 0; + } + } else { + for_each_sgtable_sg(userptr->sgt, sg, si) { + (*ents)[si].addr = cpu_to_le64(sg_phys(sg)); + (*ents)[si].length = cpu_to_le32(sg->length); + (*ents)[si].padding = 0; + } + } + + *nents = count; + return 0; +} + +static struct sg_table * +virtio_gpu_userptr_get_sg_table(struct drm_gem_object *obj) +{ + struct virtio_gpu_object *bo = gem_to_virtio_gpu_obj(obj); + struct virtio_gpu_object_userptr *userptr = to_virtio_gpu_userptr(bo); + int ret; + + mutex_lock(&userptr->lock); + if (!userptr->pages) { + ret = userptr->ops->get_pages(userptr); + if (ret) { + mutex_unlock(&userptr->lock); + return ERR_PTR(ret); + } + } + mutex_unlock(&userptr->lock); + + /* PRIME takes ownership of the returned table. */ + return drm_prime_pages_to_sg(obj->dev, userptr->pages, userptr->npages); +} + +static int +virtio_gpu_userptr_init(struct drm_device *dev, struct drm_file *file, + struct virtio_gpu_object_userptr *userptr, + struct virtio_gpu_object_params *params, + const struct virtio_gpu_object_userptr_ops *ops) +{ + struct drm_gem_object *obj; + int ret; + + userptr->start = params->userptr; + userptr->npages = params->size >> PAGE_SHIFT; + userptr->flags = params->blob_flags; + + mutex_init(&userptr->lock); + userptr->vgdev = dev->dev_private; + userptr->file = file; + userptr->ops = ops; + + /* + * Allocate the resource id before GEM init so a failure here can + * unwind with a plain kfree and does not need a special id=0 guard + * in the shared resource_id_put helper. + */ + ret = virtio_gpu_resource_id_get(userptr->vgdev, + &userptr->base.hw_res_handle); + if (ret) { + mutex_destroy(&userptr->lock); + return ret; + } + + obj = &userptr->base.base.base; + obj->funcs = &virtio_gpu_userptr_funcs; + + drm_gem_private_object_init(dev, obj, params->size); + INIT_LIST_HEAD(&userptr->base.restore_node); + + return 0; +} + +static const struct virtio_gpu_object_userptr_ops virtio_gpu_userptr_ops = { + .get_pages = virtio_gpu_userptr_get_pages, + .put_pages = virtio_gpu_userptr_put_pages, +}; + +int virtio_gpu_userptr_create(struct virtio_gpu_device *vgdev, + struct drm_file *file, + struct virtio_gpu_object_params *params, + struct virtio_gpu_object **bo_ptr) +{ + struct virtio_gpu_object_userptr *userptr; + struct virtio_gpu_mem_entry *ents = NULL; + struct sg_table *sgt; + struct mm_struct *mm; + unsigned long lock_limit; + unsigned long start; + unsigned long end; + s64 new_pinned; + unsigned int nents; + int ret; + + *bo_ptr = NULL; + + if (!params->size || !IS_ALIGNED(params->size, PAGE_SIZE) || + params->userptr != (unsigned long)params->userptr) + return -EINVAL; + + start = params->userptr; + if (!IS_ALIGNED(start, PAGE_SIZE) || + check_add_overflow(start, (unsigned long)params->size, &end)) + return -EINVAL; + + if (!can_do_mlock()) + return -EPERM; + + if (params->size >> PAGE_SHIFT > INT_MAX) + return -E2BIG; + + if (!access_ok((void __user *)start, params->size)) + return -EFAULT; + + userptr = kzalloc_obj(*userptr); + if (!userptr) + return -ENOMEM; + + ret = virtio_gpu_userptr_init(vgdev->ddev, file, userptr, params, + &virtio_gpu_userptr_ops); + if (ret) { + kfree(userptr); + return ret; + } + + mm = current->mm; + mmgrab(mm); + lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; + new_pinned = atomic64_add_return(userptr->npages, &mm->pinned_vm); + if (new_pinned < 0 || + (new_pinned > lock_limit && !capable(CAP_IPC_LOCK))) { + atomic64_sub(userptr->npages, &mm->pinned_vm); + mmdrop(mm); + ret = new_pinned < 0 ? -EOVERFLOW : -ENOMEM; + goto err_cleanup; + } + userptr->mm = mm; + + mutex_lock(&userptr->lock); + ret = userptr->ops->get_pages(userptr); + mutex_unlock(&userptr->lock); + if (ret) + goto err_cleanup; + + sgt = drm_prime_pages_to_sg(vgdev->ddev, userptr->pages, + userptr->npages); + if (IS_ERR(sgt)) { + ret = PTR_ERR(sgt); + goto err_cleanup; + } + + userptr->sgt = sgt; + + /* + * Match shmem blobs: only DMA-map when the virtio DMA API is in + * use. Mapping unconditionally can create SWIOTLB bounce buffers + * that get copied back over guest pages on unmap even though the + * host was given sg_phys() addresses. + */ + if (virtio_gpu_use_dma_api(vgdev->vdev)) { + enum dma_data_direction dir = + (userptr->flags & VIRTGPU_BLOB_FLAG_USERPTR_RDONLY) ? + DMA_TO_DEVICE : DMA_BIDIRECTIONAL; + + ret = dma_map_sgtable(drm_dev_dma_dev(vgdev->ddev), sgt, + dir, 0); + if (ret) + goto err_cleanup; + + userptr->dma_dir = dir; + userptr->dma_mapped = true; + } + + ret = virtio_gpu_userptr_get_entries(vgdev, userptr, &ents, &nents); + if (ret) + goto err_cleanup; + + virtio_gpu_cmd_resource_create_blob(vgdev, &userptr->base, params, ents, + nents); + + *bo_ptr = &userptr->base; + return 0; + +err_cleanup: + virtio_gpu_cleanup_object(&userptr->base); + return ret; +} -- 2.34.1
