virtqueue_add_packed() only supports virtual addresses, dma is completed in virtqueue_add_packed().
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_packed(). This patch stipulates that if sg->dma_address is not NULL, use this address as the DMA address. And record this information in extra->flags, which can be skipped when executing dma unmap. extra->flags |= VRING_DESC_F_PREDMA; This relies on the previous patch, in the indirect scenario, for each desc allocated, an extra is allocated at the same time. Signed-off-by: Xuan Zhuo <[email protected]> --- drivers/virtio/virtio_ring.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index add8430d9678..e165bc2e1344 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -1010,6 +1010,9 @@ static void vring_unmap_extra_packed(const struct vring_virtqueue *vq, (flags & VRING_DESC_F_WRITE) ? DMA_FROM_DEVICE : DMA_TO_DEVICE); } else { + if (flags & VRING_DESC_F_PREDMA) + return; + dma_unmap_page(vring_dma_dev(vq), extra->addr, extra->len, (flags & VRING_DESC_F_WRITE) ? @@ -1092,6 +1095,8 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq, extra->addr = addr; extra->len = sg->length; extra->flags = flags; + if (sg_is_predma(sg)) + extra->flags |= VRING_DESC_F_PREDMA; i++; } @@ -1249,9 +1254,14 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq, if (unlikely(vq->use_dma_api)) { vq->packed.desc_extra[curr].addr = addr; vq->packed.desc_extra[curr].len = sg->length; - vq->packed.desc_extra[curr].flags = - le16_to_cpu(flags); } + + vq->packed.desc_extra[curr].flags = le16_to_cpu(flags); + + if (sg_is_predma(sg)) + vq->packed.desc_extra[curr].flags |= + VRING_DESC_F_PREDMA; + prev = curr; curr = vq->packed.desc_extra[curr].next; -- 2.31.0 _______________________________________________ Virtualization mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/virtualization
