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 | 38 +++++++++++++++++++++++++++--------- 1 file changed, 29 insertions(+), 9 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index e2fc50c05bec..bd5e84afab37 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; /* DMA mapping is done by driver. */ }; struct vring_desc_state_packed { @@ -356,8 +357,14 @@ static struct device *vring_dma_dev(const struct vring_virtqueue *vq) /* Map one sg entry. */ static int vring_map_one_sg(const struct vring_virtqueue *vq, struct scatterlist *sg, - enum dma_data_direction direction, static dma_addr_t *addr) + enum dma_data_direction direction, + bool premapped, dma_addr_t *addr) { + if (premapped) { + *addr = sg_dma_address(sg); + return 0; + } + if (!vq->use_dma_api) { /* * If DMA is not used, KMSAN doesn't know that the scatterlist @@ -445,7 +452,7 @@ 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; @@ -462,6 +469,9 @@ 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, @@ -532,6 +542,7 @@ 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); @@ -595,7 +606,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, for (sg = sgs[n]; sg; sg = sg_next(sg)) { dma_addr_t addr; - if (vring_map_one_sg(vq, sg, DMA_TO_DEVICE, &addr)) + if (vring_map_one_sg(vq, sg, DMA_TO_DEVICE, premapped, &addr)) goto unmap_release; prev = i; @@ -611,7 +622,7 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, for (sg = sgs[n]; sg; sg = sg_next(sg)) { dma_addr_t addr; - if (vring_map_one_sg(vq, sg, DMA_FROM_DEVICE, &addr)) + if (vring_map_one_sg(vq, sg, DMA_FROM_DEVICE, premapped, &addr)) goto unmap_release; prev = i; @@ -657,6 +668,7 @@ 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 @@ -686,6 +698,14 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, return 0; unmap_release: + if (premapped) { + if (indirect) + kfree(desc); + + END_USE(vq); + return -ENOMEM; + } + err_idx = i; if (indirect) @@ -700,7 +720,7 @@ 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); } if (indirect) @@ -757,12 +777,12 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, i = head; while (vq->split.vring.desc[i].flags & nextflag) { - vring_unmap_one_split(vq, i); + vring_unmap_one_split(vq, i, state->premapped); i = vq->split.desc_extra[i].next; vq->vq.num_free++; } - vring_unmap_one_split(vq, i); + vring_unmap_one_split(vq, i, state->premapped); vq->split.desc_extra[i].next = vq->free_head; vq->free_head = head; @@ -783,7 +803,7 @@ 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)); - if (vq->use_dma_api) { + if (vq->use_dma_api && !state->premapped) { for (j = 0; j < len / sizeof(struct vring_desc); j++) vring_unmap_one_split_indirect(vq, &indir_desc[j]); } @@ -2143,7 +2163,7 @@ 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
