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 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.
On the indirect path, if dma_address is used, desc_state.indir_desc will
be mixed with VRING_INDIRECT_NO_DMA_MAP. So when do unmap, we can pass it.
Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
---
drivers/virtio/virtio_ring.c | 18 ++++++++++++------
1 file changed, 12 insertions(+), 6 deletions(-)
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 11827d2e56a8..b23d301effb5 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1331,6 +1331,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
unsigned int i, n;
u16 head, id;
dma_addr_t addr;
+ bool do_map;
head = vq->packed.next_avail_idx;
desc = alloc_indirect_packed(total_sg, gfp);
@@ -1348,7 +1349,8 @@ 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))
+ do_map = !sgs[0]->dma_address;
+ if (do_map && virtqueue_map_sgs(vq, sgs, total_sg, out_sgs, in_sgs))
return -ENOMEM;
for (n = 0; n < out_sgs + in_sgs; n++) {
@@ -1408,7 +1410,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
/* Store token and indirect buffer state. */
vq->packed.desc_state[id].num = 1;
vq->packed.desc_state[id].data = data;
- vq->packed.desc_state[id].indir_desc = desc;
+ vq->packed.desc_state[id].indir_desc = desc_mix_dma_map(do_map, desc);
vq->packed.desc_state[id].last = id;
vq->num_added += 1;
@@ -1419,7 +1421,8 @@ 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 (do_map)
+ virtqueue_unmap_sgs(vq, sgs, total_sg, out_sgs, in_sgs);
kfree(desc);
@@ -1633,14 +1636,17 @@ static void detach_buf_packed(struct vring_virtqueue *vq,
}
if (vq->indirect) {
+ struct vring_packed_desc *mix;
u32 len;
/* Free the indirect table, if any, now that it's unmapped. */
- desc = state->indir_desc;
- if (!desc)
+ mix = state->indir_desc;
+ if (!mix)
return;
- if (vq->use_dma_api) {
+ desc = desc_rm_dma_map(mix);
+
+ if (vq->use_dma_api && desc_map_inter(mix)) {
len = vq->packed.desc_extra[id].len;
for (i = 0; i < len / sizeof(struct vring_packed_desc);
i++)
--
2.32.0.3.g01195cf9f
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