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 virtqueue_add_split(). And record this premapped information in desc_extra[head]->premapped, which can be skipped when executing dma unmap. Signed-off-by: Xuan Zhuo <[email protected]> --- drivers/virtio/virtio_ring.c | 58 +++++++++++++++++++++++++++--------- 1 file changed, 44 insertions(+), 14 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 2f9572c3628c..35cb804dcf2d 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -83,6 +83,7 @@ struct vring_desc_extra { u32 len; /* Descriptor length. */ u16 flags; /* Descriptor flags. */ u16 next; /* The next desc state in a list. */ + bool premapped; }; struct vring_virtqueue { @@ -387,7 +388,7 @@ 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; @@ -404,6 +405,9 @@ 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, @@ -474,7 +478,8 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, unsigned int in_sgs, void *data, void *ctx, - gfp_t gfp) + gfp_t gfp, + bool premapped) { struct vring_virtqueue *vq = to_vvq(_vq); struct scatterlist *sg; @@ -535,9 +540,16 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, for (n = 0; n < out_sgs; n++) { for (sg = sgs[n]; sg; sg = sg_next(sg)) { - dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_TO_DEVICE); - if (vring_mapping_error(vq, addr)) - goto unmap_release; + dma_addr_t addr; + + if (premapped) { + addr = sg_dma_address(sg); + + } else { + addr = vring_map_one_sg(vq, sg, DMA_TO_DEVICE); + if (vring_mapping_error(vq, addr)) + goto unmap_release; + } prev = i; /* Note that we trust indirect descriptor @@ -550,9 +562,16 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, } for (; n < (out_sgs + in_sgs); n++) { for (sg = sgs[n]; sg; sg = sg_next(sg)) { - dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_FROM_DEVICE); - if (vring_mapping_error(vq, addr)) - goto unmap_release; + dma_addr_t addr; + + if (premapped) { + addr = sg_dma_address(sg); + + } else { + addr = vring_map_one_sg(vq, sg, DMA_FROM_DEVICE); + if (vring_mapping_error(vq, addr)) + goto unmap_release; + } prev = i; /* Note that we trust indirect descriptor @@ -602,6 +621,8 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, else vq->split.desc_state[head].indir_desc = ctx; + vq->split.desc_extra[head].premapped = premapped; + /* Put entry in available array (but don't update avail->idx until they * do sync). */ avail = vq->split.avail_idx_shadow & (vq->split.vring.num - 1); @@ -626,6 +647,9 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, return 0; unmap_release: + if (premapped) + goto unmap_free; + err_idx = i; if (indirect) @@ -640,9 +664,10 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, vring_unmap_one_split_indirect(vq, &desc[i]); i = virtio16_to_cpu(_vq->vdev, desc[i].next); } else - i = vring_unmap_one_split(vq, i); + i = vring_unmap_one_split(vq, i, false); } +unmap_free: if (indirect) kfree(desc); @@ -686,20 +711,23 @@ 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_extra[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; @@ -721,8 +749,10 @@ 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; @@ -1788,7 +1818,7 @@ static inline int virtqueue_add(struct virtqueue *_vq, return vq->packed_ring ? virtqueue_add_packed(_vq, sgs, total_sg, out_sgs, in_sgs, data, ctx, gfp) : virtqueue_add_split(_vq, sgs, total_sg, - out_sgs, in_sgs, data, ctx, gfp); + out_sgs, in_sgs, data, ctx, gfp, premapped); } /** -- 2.31.0 _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
