// SPDX-License-Identifier: MIT
/*
 * Copyright (C) 2015 Red Hat, Inc.
 * All Rights Reserved.
 *
 * Authors:
 *    Dave Airlie
 *    Alon Levy
 */

#include <linux/dma-fence-unwrap.h>
#include <linux/file.h>
#include <linux/sync_file.h>
#include <linux/uaccess.h>

#include <drm/drm_file.h>
#include <drm/virtgpu_drm.h>

#include "virtgpu_drv.h"

struct virtio_gpu_submit {
	struct virtio_gpu_object_array *buflist;
	struct drm_virtgpu_execbuffer *exbuf;
	struct virtio_gpu_fence *out_fence;
	struct virtio_gpu_fpriv *vfpriv;
	struct virtio_gpu_device *vgdev;
	struct sync_file *sync_file;
	struct drm_file *file;
	int out_fence_fd;
	u64 fence_ctx;
	u32 ring_idx;
	void *buf;
};

static int virtio_gpu_do_fence_wait(struct virtio_gpu_submit *submit,
				    struct dma_fence *in_fence)
{
	u32 context = submit->fence_ctx + submit->ring_idx;

	if (dma_fence_match_context(in_fence, context))
		return 0;

	return dma_fence_wait(in_fence, true);
}

static int virtio_gpu_dma_fence_wait(struct virtio_gpu_submit *submit,
				     struct dma_fence *fence)
{
	struct dma_fence_unwrap itr;
	struct dma_fence *f;
	int err;

	dma_fence_unwrap_for_each(f, &itr, fence) {
		err = virtio_gpu_do_fence_wait(submit, f);
		if (err)
			return err;
	}

	return 0;
}

static int virtio_gpu_fence_event_create(struct drm_device *dev,
					 struct drm_file *file,
					 struct virtio_gpu_fence *fence,
					 u32 ring_idx)
{
	struct virtio_gpu_fence_event *e = NULL;
	int ret;

	e = kzalloc(sizeof(*e), GFP_KERNEL);
	if (!e)
		return -ENOMEM;

	e->event.type = VIRTGPU_EVENT_FENCE_SIGNALED;
	e->event.length = sizeof(e->event);

	ret = drm_event_reserve_init(dev, file, &e->base, &e->event);
	if (ret) {
		kfree(e);
		return ret;
	}

	fence->e = e;

	return 0;
}

static int virtio_gpu_init_submit_buflist(struct virtio_gpu_submit *submit)
{
	struct drm_virtgpu_execbuffer *exbuf = submit->exbuf;
	u32 *bo_handles;

	if (!exbuf->num_bo_handles)
		return 0;

	bo_handles = kvmalloc_array(exbuf->num_bo_handles, sizeof(*bo_handles),
				    GFP_KERNEL);
	if (!bo_handles)
		return -ENOMEM;

	if (copy_from_user(bo_handles, u64_to_user_ptr(exbuf->bo_handles),
			   exbuf->num_bo_handles * sizeof(*bo_handles))) {
		kvfree(bo_handles);
		return -EFAULT;
	}

	submit->buflist = virtio_gpu_array_from_handles(submit->file, bo_handles,
							exbuf->num_bo_handles);
	if (!submit->buflist) {
		kvfree(bo_handles);
		return -ENOENT;
	}

	kvfree(bo_handles);

	return 0;
}

static void virtio_gpu_cleanup_submit(struct virtio_gpu_submit *submit)
{
	if (!IS_ERR(submit->buf))
		kvfree(submit->buf);

	if (submit->buflist)
		virtio_gpu_array_put_free(submit->buflist);

	if (submit->out_fence_fd >= 0)
		put_unused_fd(submit->out_fence_fd);

	if (submit->out_fence)
		dma_fence_put(&submit->out_fence->f);

	if (submit->sync_file)
		fput(submit->sync_file->file);
}

static void virtio_gpu_submit(struct virtio_gpu_submit *submit)
{
	virtio_gpu_cmd_submit(submit->vgdev, submit->buf, submit->exbuf->size,
			      submit->vfpriv->ctx_id, submit->buflist,
			      submit->out_fence);
	virtio_gpu_notify(submit->vgdev);
}

static void virtio_gpu_complete_submit(struct virtio_gpu_submit *submit)
{
	submit->buf = NULL;
	submit->buflist = NULL;
	submit->sync_file = NULL;
	submit->out_fence_fd = -1;
}

static int virtio_gpu_init_submit(struct virtio_gpu_submit *submit,
				  struct drm_virtgpu_execbuffer *exbuf,
				  struct drm_device *dev,
				  struct drm_file *file,
				  u64 fence_ctx, u32 ring_idx)
{
	struct virtio_gpu_fpriv *vfpriv = file->driver_priv;
	struct virtio_gpu_device *vgdev = dev->dev_private;
	struct virtio_gpu_fence *out_fence;
	bool drm_fence_event;
	int err;

	memset(submit, 0, sizeof(*submit));

	if ((exbuf->flags & VIRTGPU_EXECBUF_RING_IDX) &&
	    (vfpriv->ring_idx_mask & BIT_ULL(ring_idx)))
		drm_fence_event = true;
	else
		drm_fence_event = false;

	if ((exbuf->flags & VIRTGPU_EXECBUF_FENCE_FD_OUT) ||
	    exbuf->num_bo_handles ||
	    drm_fence_event)
		out_fence = virtio_gpu_fence_alloc(vgdev, fence_ctx, ring_idx);
	else
		out_fence = NULL;

	if (drm_fence_event) {
		err = virtio_gpu_fence_event_create(dev, file, out_fence, ring_idx);
		if (err) {
			dma_fence_put(&out_fence->f);
			return err;
		}
	}

	submit->out_fence = out_fence;
	submit->fence_ctx = fence_ctx;
	submit->ring_idx = ring_idx;
	submit->out_fence_fd = -1;
	submit->vfpriv = vfpriv;
	submit->vgdev = vgdev;
	submit->exbuf = exbuf;
	submit->file = file;

	err = virtio_gpu_init_submit_buflist(submit);
	if (err)
		return err;

	submit->buf = vmemdup_user(u64_to_user_ptr(exbuf->command), exbuf->size);
	if (IS_ERR(submit->buf))
		return PTR_ERR(submit->buf);

	if (exbuf->flags & VIRTGPU_EXECBUF_FENCE_FD_OUT) {
		err = get_unused_fd_flags(O_CLOEXEC);
		if (err < 0)
			return err;

		submit->out_fence_fd = err;

		submit->sync_file = sync_file_create(&out_fence->f);
		if (!submit->sync_file)
			return -ENOMEM;
	}

	return 0;
}

static int virtio_gpu_wait_in_fence(struct virtio_gpu_submit *submit)
{
	int ret = 0;

	if (submit->exbuf->flags & VIRTGPU_EXECBUF_FENCE_FD_IN) {
		struct dma_fence *in_fence =
				sync_file_get_fence(submit->exbuf->fence_fd);
		if (!in_fence)
			return -EINVAL;

		/*
		 * Wait if the fence is from a foreign context, or if the
		 * fence array contains any fence from a foreign context.
		 */
		ret = virtio_gpu_dma_fence_wait(submit, in_fence);

		dma_fence_put(in_fence);
	}

	return ret;
}

static void virtio_gpu_install_out_fence_fd(struct virtio_gpu_submit *submit)
{
	if (submit->sync_file) {
		submit->exbuf->fence_fd = submit->out_fence_fd;
		fd_install(submit->out_fence_fd, submit->sync_file->file);
	}
}

static int virtio_gpu_lock_buflist(struct virtio_gpu_submit *submit)
{
	if (submit->buflist)
		return virtio_gpu_array_lock_resv(submit->buflist);

	return 0;
}

int virtio_gpu_execbuffer_ioctl(struct drm_device *dev, void *data,
				struct drm_file *file)
{
	struct virtio_gpu_device *vgdev = dev->dev_private;
	struct virtio_gpu_fpriv *vfpriv = file->driver_priv;
	u64 fence_ctx = vgdev->fence_drv.context;
	struct drm_virtgpu_execbuffer *exbuf = data;
	struct virtio_gpu_submit submit;
	u32 ring_idx = 0;
	int ret = -EINVAL;

	if (!vgdev->has_virgl_3d)
		return -ENOSYS;

	if (exbuf->flags & ~VIRTGPU_EXECBUF_FLAGS)
		return ret;

	if (exbuf->flags & VIRTGPU_EXECBUF_RING_IDX) {
		if (exbuf->ring_idx >= vfpriv->num_rings)
			return ret;

		if (!vfpriv->base_fence_ctx)
			return ret;

		fence_ctx = vfpriv->base_fence_ctx;
		ring_idx = exbuf->ring_idx;
	}

	virtio_gpu_create_context(dev, file);

	ret = virtio_gpu_init_submit(&submit, exbuf, dev, file,
				     fence_ctx, ring_idx);
	if (ret)
		goto cleanup;

	/*
	 * Await in-fences in the end of the job submission path to
	 * optimize the path by proceeding directly to the submission
	 * to virtio after the waits.
	 */
	ret = virtio_gpu_wait_in_fence(&submit);
	if (ret)
		goto cleanup;

	ret = virtio_gpu_lock_buflist(&submit);
	if (ret)
		goto cleanup;

	virtio_gpu_submit(&submit);

	/*
	 * Set up usr-out data after submitting the job to optimize
	 * the job submission path.
	 */
	virtio_gpu_install_out_fence_fd(&submit);
	virtio_gpu_complete_submit(&submit);
cleanup:
	virtio_gpu_cleanup_submit(&submit);

	return ret;
}