virtio core only supports virtual addresses, dma is completed in virtio
core.
In some scenarios (such as the AF_XDP), the memory is allocated
and DMA mapping is completed in advance, so it is necessary for us to
support passing the DMA address to virtio core.
Drives can use sg->dma_address to pass the mapped dma address to virtio
core. If one sg->dma_address is used then all sgs must use sg->dma_address,
otherwise all dma_address must be null when passing it to the APIs of
virtio.
Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
---
drivers/virtio/virtio_ring.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 4b6c6da4cdb4..0bc011e6e96e 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1346,6 +1346,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
unsigned int i, n;
u16 head, id;
dma_addr_t addr;
+ bool dma_map_internal;
head = vq->packed.next_avail_idx;
desc = alloc_indirect_packed(total_sg, gfp);
@@ -1363,7 +1364,8 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
id = vq->free_head;
BUG_ON(id == vq->packed.vring.num);
- if (virtqueue_map_sgs(vq, sgs, total_sg, out_sgs, in_sgs))
+ dma_map_internal = !sgs[0]->dma_address;
+ if (dma_map_internal && virtqueue_map_sgs(vq, sgs, total_sg, out_sgs, in_sgs))
goto err_map;
for (n = 0; n < out_sgs + in_sgs; n++) {
@@ -1425,6 +1427,8 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
vq->packed.desc_state[id].data = data;
vq->packed.desc_state[id].indir_desc = desc;
vq->packed.desc_state[id].last = id;
+ vq->packed.desc_state[id].flags = dma_map_internal ? VRING_STATE_F_MAP_INTERNAL : 0;
+
vq->num_added += 1;
@@ -1434,7 +1438,8 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
return 0;
unmap_release:
- virtqueue_unmap_sgs(vq, sgs, total_sg, out_sgs, in_sgs);
+ if (dma_map_internal)
+ virtqueue_unmap_sgs(vq, sgs, total_sg, out_sgs, in_sgs);
err_map:
kfree(desc);
@@ -1661,7 +1666,7 @@ static void detach_buf_packed(struct vring_virtqueue *vq,
if (!desc)
return;
- if (vq->use_dma_api) {
+ if (vq->use_dma_api && dma_map_internal) {
len = vq->packed.desc_extra[id].len;
for (i = 0; i < len / sizeof(struct vring_packed_desc);
i++)
--
2.32.0.3.g01195cf9f
