virtqueue_add_split() only supports virtual addresses, dma is completed in virtqueue_add_split().
In some scenarios (such as the AF_XDP scenario), the memory is allocated and DMA is completed in advance, so it is necessary for us to support passing the DMA address to virtio core. Signed-off-by: Xuan Zhuo <[email protected]> --- drivers/virtio/virtio_ring.c | 100 +++++++++++++++++++++++++++++++++-- include/linux/virtio.h | 5 ++ 2 files changed, 100 insertions(+), 5 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 47b6f9152f9f..a31155abe101 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -70,6 +70,7 @@ struct vring_desc_state_split { void *data; /* Data for callback. */ struct vring_desc *indir_desc; /* Indirect descriptor, if any. */ + bool premapped; }; struct vring_desc_state_packed { @@ -440,7 +441,7 @@ static void vring_unmap_one_split_indirect(const struct vring_virtqueue *vq, } static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq, - unsigned int i) + unsigned int i, bool premapped) { struct vring_desc_extra *extra = vq->split.desc_extra; u16 flags; @@ -457,6 +458,9 @@ static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq, (flags & VRING_DESC_F_WRITE) ? DMA_FROM_DEVICE : DMA_TO_DEVICE); } else { + if (premapped) + goto out; + dma_unmap_page(vring_dma_dev(vq), extra[i].addr, extra[i].len, @@ -788,6 +792,47 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, return err; } +static inline int virtqueue_add_split_premapped(struct virtqueue *_vq, + struct scatterlist *sgs[], + unsigned int total_sg, + unsigned int out_sgs, + unsigned int in_sgs, + void *data, + void *ctx, + gfp_t gfp) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + struct vring_desc *desc; + int head; + int err; + + START_USE(vq); + + /* check vq state and try to alloc desc for indirect. */ + err = virtqueue_add_split_prepare(vq, total_sg, out_sgs, data, ctx, gfp, &desc); + if (err) + goto end; + + head = vq->free_head; + err = virtqueue_add_split_vring(vq, sgs, total_sg, out_sgs, in_sgs, desc); + if (err) + goto err; + + /* Store token and indirect buffer state. */ + vq->split.desc_state[head].data = data; + vq->split.desc_state[head].indir_desc = desc ? desc : ctx; + vq->split.desc_state[head].premapped = true; + + goto end; + +err: + kfree(desc); + +end: + END_USE(vq); + return err; +} + static bool virtqueue_kick_prepare_split(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); @@ -824,20 +869,23 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, { unsigned int i, j; __virtio16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT); + bool premapped; /* Clear data ptr. */ vq->split.desc_state[head].data = NULL; + premapped = vq->split.desc_state[head].premapped; + /* Put back on free list: unmap first-level descriptors and find end */ i = head; while (vq->split.vring.desc[i].flags & nextflag) { - vring_unmap_one_split(vq, i); + vring_unmap_one_split(vq, i, premapped); i = vq->split.desc_extra[i].next; vq->vq.num_free++; } - vring_unmap_one_split(vq, i); + vring_unmap_one_split(vq, i, premapped); vq->split.desc_extra[i].next = vq->free_head; vq->free_head = head; @@ -859,8 +907,10 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, VRING_DESC_F_INDIRECT)); BUG_ON(len == 0 || len % sizeof(struct vring_desc)); - for (j = 0; j < len / sizeof(struct vring_desc); j++) - vring_unmap_one_split_indirect(vq, &indir_desc[j]); + if (!premapped) { + for (j = 0; j < len / sizeof(struct vring_desc); j++) + vring_unmap_one_split_indirect(vq, &indir_desc[j]); + } kfree(indir_desc); vq->split.desc_state[head].indir_desc = NULL; @@ -2204,6 +2254,21 @@ static inline int virtqueue_add(struct virtqueue *_vq, out_sgs, in_sgs, data, ctx, gfp); } +static inline int virtqueue_add_premapped(struct virtqueue *_vq, + struct scatterlist *sgs[], + unsigned int total_sg, + unsigned int out_sgs, + unsigned int in_sgs, + void *data, + void *ctx, + gfp_t gfp) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + + return virtqueue_add_split_premapped(_vq, sgs, total_sg, out_sgs, + in_sgs, data, ctx, gfp); +} + /** * virtqueue_add_sgs - expose buffers to other end * @_vq: the struct virtqueue we're talking about. @@ -2261,6 +2326,31 @@ int virtqueue_add_outbuf(struct virtqueue *vq, } EXPORT_SYMBOL_GPL(virtqueue_add_outbuf); +/** + * virtqueue_add_outbuf_premapped - expose output buffers to other end + * @vq: the struct virtqueue we're talking about. + * @sg: scatterlist (must be well-formed and terminated!) + * @num: the number of entries in @sg readable by other side + * @data: the token identifying the buffer. + * @gfp: how to do memory allocations (if necessary). + * + * Caller must ensure we don't call this with other virtqueue operations + * at the same time (except where noted). + * + * It is required that all addrs have completed DMA operations. And use + * sg->dma_address, sg->length to pass addr and length. + * + * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO). + */ +int virtqueue_add_outbuf_premapped(struct virtqueue *vq, + struct scatterlist *sg, unsigned int num, + void *data, + gfp_t gfp) +{ + return virtqueue_add_premapped(vq, &sg, num, 1, 0, data, NULL, gfp); +} +EXPORT_SYMBOL_GPL(virtqueue_add_outbuf_premapped); + /** * virtqueue_add_inbuf - expose input buffers to other end * @vq: the struct virtqueue we're talking about. diff --git a/include/linux/virtio.h b/include/linux/virtio.h index dcab9c7e8784..d8b472a7dcae 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h @@ -43,6 +43,11 @@ int virtqueue_add_outbuf(struct virtqueue *vq, void *data, gfp_t gfp); +int virtqueue_add_outbuf_premapped(struct virtqueue *vq, + struct scatterlist *sg, unsigned int num, + void *data, + gfp_t gfp); + int virtqueue_add_inbuf(struct virtqueue *vq, struct scatterlist sg[], unsigned int num, void *data, -- 2.32.0.3.g01195cf9f _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
