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 <xuanzhuo@xxxxxxxxxxxxxxxxx>
---
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
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
