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(). Record this information in desc_state, we can skip unmap based on this when executing dma unmap. Signed-off-by: Xuan Zhuo <[email protected]> --- drivers/virtio/virtio_ring.c | 55 +++++++++++++++++++++++++++--------- 1 file changed, 42 insertions(+), 13 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index c9f194c86aec..ec622403cbd5 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 { @@ -434,7 +435,7 @@ 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; @@ -451,6 +452,9 @@ 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, @@ -521,6 +525,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, unsigned int in_sgs, void *data, void *ctx, + bool premapped, gfp_t gfp) { struct vring_virtqueue *vq = to_vvq(_vq); @@ -582,9 +587,16 @@ 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 @@ -597,9 +609,16 @@ 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 @@ -644,6 +663,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, /* Store token and indirect buffer state. */ vq->split.desc_state[head].data = data; + vq->split.desc_state[head].premapped = premapped; if (indirect) vq->split.desc_state[head].indir_desc = desc; else @@ -673,6 +693,9 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, return 0; unmap_release: + if (premapped) + goto unmap_free; + err_idx = i; if (indirect) @@ -687,9 +710,10 @@ 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); @@ -733,20 +757,23 @@ 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; @@ -768,8 +795,10 @@ 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; @@ -2095,7 +2124,7 @@ 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, premapped, gfp); } /** -- 2.32.0.3.g01195cf9f _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
