introduce virtqueue_get_buf_ctx_dma() to collect the dma info when
get buf from virtio core for premapped mode.
If the virtio queue is premapped mode, the virtio-net send buf may
have many desc. Every desc dma address need to be unmap. So here we
introduce a new helper to collect the dma address of the buffer from
the virtio core.
Because the BAD_RING is called (that may set vq->broken), so
the relative "const" of vq is removed.
Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
---
drivers/virtio/virtio_ring.c | 174 +++++++++++++++++++++++++----------
include/linux/virtio.h | 16 ++++
2 files changed, 142 insertions(+), 48 deletions(-)
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 51d8f3299c10..1374b3fd447c 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -362,6 +362,45 @@ static struct device *vring_dma_dev(const struct vring_virtqueue *vq)
return vq->dma_dev;
}
+/*
+ * use_dma_api premapped -> do_unmap
+ * 1. false false false
+ * 2. true false true
+ * 3. true true false
+ *
+ * Only #3, we should return the DMA info to the driver.
+ *
+ * Return:
+ * true: the virtio core must unmap the desc
+ * false: the virtio core skip the desc unmap
+ */
+static bool vring_need_unmap(struct vring_virtqueue *vq,
+ struct virtio_dma_head *dma,
+ dma_addr_t addr, unsigned int length)
+{
+ if (vq->do_unmap)
+ return true;
+
+ if (!vq->premapped)
+ return false;
+
+ if (!dma)
+ return false;
+
+ if (unlikely(dma->next >= dma->num)) {
+ BAD_RING(vq, "premapped vq: collect dma overflow: %pad %u\n",
+ &addr, length);
+ return false;
+ }
+
+ dma->items[dma->next].addr = addr;
+ dma->items[dma->next].length = length;
+
+ ++dma->next;
+
+ return false;
+}
+
/* Map one sg entry. */
static int vring_map_one_sg(const struct vring_virtqueue *vq, struct scatterlist *sg,
enum dma_data_direction direction, dma_addr_t *addr)
@@ -440,12 +479,14 @@ static void virtqueue_init(struct vring_virtqueue *vq, u32 num)
* Split ring specific functions - *_split().
*/
-static void vring_unmap_one_split_indirect(const struct vring_virtqueue *vq,
- const struct vring_desc *desc)
+static void vring_unmap_one_split_indirect(struct vring_virtqueue *vq,
+ const struct vring_desc *desc,
+ struct virtio_dma_head *dma)
{
u16 flags;
- if (!vq->do_unmap)
+ if (!vring_need_unmap(vq, dma, virtio64_to_cpu(vq->vq.vdev, desc->addr),
+ virtio32_to_cpu(vq->vq.vdev, desc->len)))
return;
flags = virtio16_to_cpu(vq->vq.vdev, desc->flags);
@@ -457,8 +498,8 @@ static void vring_unmap_one_split_indirect(const struct vring_virtqueue *vq,
DMA_FROM_DEVICE : DMA_TO_DEVICE);
}
-static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq,
- unsigned int i)
+static unsigned int vring_unmap_one_split(struct vring_virtqueue *vq,
+ unsigned int i, struct virtio_dma_head *dma)
{
struct vring_desc_extra *extra = vq->split.desc_extra;
u16 flags;
@@ -474,17 +515,16 @@ static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq,
extra[i].len,
(flags & VRING_DESC_F_WRITE) ?
DMA_FROM_DEVICE : DMA_TO_DEVICE);
- } else {
- if (!vq->do_unmap)
- goto out;
-
- dma_unmap_page(vring_dma_dev(vq),
- extra[i].addr,
- extra[i].len,
- (flags & VRING_DESC_F_WRITE) ?
- DMA_FROM_DEVICE : DMA_TO_DEVICE);
+ goto out;
}
+ if (!vring_need_unmap(vq, dma, extra[i].addr, extra[i].len))
+ goto out;
+
+ dma_unmap_page(vring_dma_dev(vq), extra[i].addr, extra[i].len,
+ (flags & VRING_DESC_F_WRITE) ?
+ DMA_FROM_DEVICE : DMA_TO_DEVICE);
+
out:
return extra[i].next;
}
@@ -717,10 +757,10 @@ static inline int virtqueue_add_split(struct virtqueue *_vq,
if (i == err_idx)
break;
if (indirect) {
- vring_unmap_one_split_indirect(vq, &desc[i]);
+ vring_unmap_one_split_indirect(vq, &desc[i], NULL);
i = virtio16_to_cpu(_vq->vdev, desc[i].next);
} else
- i = vring_unmap_one_split(vq, i);
+ i = vring_unmap_one_split(vq, i, NULL);
}
free_indirect:
@@ -763,7 +803,7 @@ static bool virtqueue_kick_prepare_split(struct virtqueue *_vq)
}
static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head,
- void **ctx)
+ struct virtio_dma_head *dma, void **ctx)
{
unsigned int i, j;
__virtio16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT);
@@ -775,12 +815,12 @@ 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, dma);
i = vq->split.desc_extra[i].next;
vq->vq.num_free++;
}
- vring_unmap_one_split(vq, i);
+ vring_unmap_one_split(vq, i, dma);
vq->split.desc_extra[i].next = vq->free_head;
vq->free_head = head;
@@ -802,9 +842,9 @@ 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->do_unmap) {
+ if (vq->do_unmap || dma) {
for (j = 0; j < len / sizeof(struct vring_desc); j++)
- vring_unmap_one_split_indirect(vq, &indir_desc[j]);
+ vring_unmap_one_split_indirect(vq, &indir_desc[j], dma);
}
kfree(indir_desc);
@@ -822,6 +862,7 @@ static bool more_used_split(const struct vring_virtqueue *vq)
static void *virtqueue_get_buf_ctx_split(struct virtqueue *_vq,
unsigned int *len,
+ struct virtio_dma_head *dma,
void **ctx)
{
struct vring_virtqueue *vq = to_vvq(_vq);
@@ -862,7 +903,7 @@ static void *virtqueue_get_buf_ctx_split(struct virtqueue *_vq,
/* detach_buf_split clears data, so grab it now. */
ret = vq->split.desc_state[i].data;
- detach_buf_split(vq, i, ctx);
+ detach_buf_split(vq, i, dma, ctx);
vq->last_used_idx++;
/* If we expect an interrupt for the next entry, tell host
* by writing event index and flush out the write before
@@ -984,7 +1025,7 @@ static void *virtqueue_detach_unused_buf_split(struct virtqueue *_vq)
continue;
/* detach_buf_split clears data, so grab it now. */
buf = vq->split.desc_state[i].data;
- detach_buf_split(vq, i, NULL);
+ detach_buf_split(vq, i, NULL, NULL);
vq->split.avail_idx_shadow--;
vq->split.vring.avail->idx = cpu_to_virtio16(_vq->vdev,
vq->split.avail_idx_shadow);
@@ -1220,8 +1261,9 @@ static u16 packed_last_used(u16 last_used_idx)
return last_used_idx & ~(-(1 << VRING_PACKED_EVENT_F_WRAP_CTR));
}
-static void vring_unmap_extra_packed(const struct vring_virtqueue *vq,
- const struct vring_desc_extra *extra)
+static void vring_unmap_extra_packed(struct vring_virtqueue *vq,
+ const struct vring_desc_extra *extra,
+ struct virtio_dma_head *dma)
{
u16 flags;
@@ -1235,23 +1277,24 @@ static void vring_unmap_extra_packed(const struct vring_virtqueue *vq,
extra->addr, extra->len,
(flags & VRING_DESC_F_WRITE) ?
DMA_FROM_DEVICE : DMA_TO_DEVICE);
- } else {
- if (!vq->do_unmap)
- return;
-
- dma_unmap_page(vring_dma_dev(vq),
- extra->addr, extra->len,
- (flags & VRING_DESC_F_WRITE) ?
- DMA_FROM_DEVICE : DMA_TO_DEVICE);
+ return;
}
+
+ if (!vring_need_unmap(vq, dma, extra->addr, extra->len))
+ return;
+
+ dma_unmap_page(vring_dma_dev(vq), extra->addr, extra->len,
+ (flags & VRING_DESC_F_WRITE) ?
+ DMA_FROM_DEVICE : DMA_TO_DEVICE);
}
-static void vring_unmap_desc_packed(const struct vring_virtqueue *vq,
- const struct vring_packed_desc *desc)
+static void vring_unmap_desc_packed(struct vring_virtqueue *vq,
+ const struct vring_packed_desc *desc,
+ struct virtio_dma_head *dma)
{
u16 flags;
- if (!vq->do_unmap)
+ if (!vring_need_unmap(vq, dma, le64_to_cpu(desc->addr), le32_to_cpu(desc->len)))
return;
flags = le16_to_cpu(desc->flags);
@@ -1389,7 +1432,7 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
err_idx = i;
for (i = 0; i < err_idx; i++)
- vring_unmap_desc_packed(vq, &desc[i]);
+ vring_unmap_desc_packed(vq, &desc[i], NULL);
free_desc:
kfree(desc);
@@ -1539,7 +1582,7 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq,
for (n = 0; n < total_sg; n++) {
if (i == err_idx)
break;
- vring_unmap_extra_packed(vq, &vq->packed.desc_extra[curr]);
+ vring_unmap_extra_packed(vq, &vq->packed.desc_extra[curr], NULL);
curr = vq->packed.desc_extra[curr].next;
i++;
if (i >= vq->packed.vring.num)
@@ -1600,7 +1643,9 @@ static bool virtqueue_kick_prepare_packed(struct virtqueue *_vq)
}
static void detach_buf_packed(struct vring_virtqueue *vq,
- unsigned int id, void **ctx)
+ unsigned int id,
+ struct virtio_dma_head *dma,
+ void **ctx)
{
struct vring_desc_state_packed *state = NULL;
struct vring_packed_desc *desc;
@@ -1615,11 +1660,10 @@ static void detach_buf_packed(struct vring_virtqueue *vq,
vq->free_head = id;
vq->vq.num_free += state->num;
- if (unlikely(vq->do_unmap)) {
+ if (vq->do_unmap || dma) {
curr = id;
for (i = 0; i < state->num; i++) {
- vring_unmap_extra_packed(vq,
- &vq->packed.desc_extra[curr]);
+ vring_unmap_extra_packed(vq, &vq->packed.desc_extra[curr], dma);
curr = vq->packed.desc_extra[curr].next;
}
}
@@ -1632,11 +1676,11 @@ static void detach_buf_packed(struct vring_virtqueue *vq,
if (!desc)
return;
- if (vq->do_unmap) {
+ if (vq->do_unmap || dma) {
len = vq->packed.desc_extra[id].len;
for (i = 0; i < len / sizeof(struct vring_packed_desc);
i++)
- vring_unmap_desc_packed(vq, &desc[i]);
+ vring_unmap_desc_packed(vq, &desc[i], dma);
}
kfree(desc);
state->indir_desc = NULL;
@@ -1672,6 +1716,7 @@ static bool more_used_packed(const struct vring_virtqueue *vq)
static void *virtqueue_get_buf_ctx_packed(struct virtqueue *_vq,
unsigned int *len,
+ struct virtio_dma_head *dma,
void **ctx)
{
struct vring_virtqueue *vq = to_vvq(_vq);
@@ -1712,7 +1757,7 @@ static void *virtqueue_get_buf_ctx_packed(struct virtqueue *_vq,
/* detach_buf_packed clears data, so grab it now. */
ret = vq->packed.desc_state[id].data;
- detach_buf_packed(vq, id, ctx);
+ detach_buf_packed(vq, id, dma, ctx);
last_used += vq->packed.desc_state[id].num;
if (unlikely(last_used >= vq->packed.vring.num)) {
@@ -1877,7 +1922,7 @@ static void *virtqueue_detach_unused_buf_packed(struct virtqueue *_vq)
continue;
/* detach_buf clears data, so grab it now. */
buf = vq->packed.desc_state[i].data;
- detach_buf_packed(vq, i, NULL);
+ detach_buf_packed(vq, i, NULL, NULL);
END_USE(vq);
return buf;
}
@@ -2417,11 +2462,44 @@ void *virtqueue_get_buf_ctx(struct virtqueue *_vq, unsigned int *len,
{
struct vring_virtqueue *vq = to_vvq(_vq);
- return vq->packed_ring ? virtqueue_get_buf_ctx_packed(_vq, len, ctx) :
- virtqueue_get_buf_ctx_split(_vq, len, ctx);
+ return vq->packed_ring ? virtqueue_get_buf_ctx_packed(_vq, len, NULL, ctx) :
+ virtqueue_get_buf_ctx_split(_vq, len, NULL, ctx);
}
EXPORT_SYMBOL_GPL(virtqueue_get_buf_ctx);
+/**
+ * virtqueue_get_buf_ctx_dma - get the next used buffer with the dma info
+ * @_vq: the struct virtqueue we're talking about.
+ * @len: the length written into the buffer
+ * @dma: the head of the array to store the dma info
+ * @ctx: extra context for the token
+ *
+ * If the device wrote data into the buffer, @len will be set to the
+ * amount written. This means you don't need to clear the buffer
+ * beforehand to ensure there's no data leakage in the case of short
+ * writes.
+ *
+ * Caller must ensure we don't call this with other virtqueue
+ * operations at the same time (except where noted).
+ *
+ * We store the dma info of every descriptor of this buf to the dma->items
+ * array. If the array size is too small, some dma info may be missed, so
+ * the caller must ensure the array is large enough. The dma->next is the out
+ * value to the caller, indicates the num of the used items.
+ *
+ * Returns NULL if there are no used buffers, or the "data" token
+ * handed to virtqueue_add_*().
+ */
+void *virtqueue_get_buf_ctx_dma(struct virtqueue *_vq, unsigned int *len,
+ struct virtio_dma_head *dma, void **ctx)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ return vq->packed_ring ? virtqueue_get_buf_ctx_packed(_vq, len, dma, ctx) :
+ virtqueue_get_buf_ctx_split(_vq, len, dma, ctx);
+}
+EXPORT_SYMBOL_GPL(virtqueue_get_buf_ctx_dma);
+
void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len)
{
return virtqueue_get_buf_ctx(_vq, len, NULL);
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 4cc614a38376..572aecec205b 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -75,6 +75,22 @@ void *virtqueue_get_buf(struct virtqueue *vq, unsigned int *len);
void *virtqueue_get_buf_ctx(struct virtqueue *vq, unsigned int *len,
void **ctx);
+struct virtio_dma_item {
+ dma_addr_t addr;
+ unsigned int length;
+};
+
+struct virtio_dma_head {
+ /* total num of items. */
+ u16 num;
+ /* point to the next item to store dma info. */
+ u16 next;
+ struct virtio_dma_item items[];
+};
+
+void *virtqueue_get_buf_ctx_dma(struct virtqueue *_vq, unsigned int *len,
+ struct virtio_dma_head *dma, void **ctx);
+
void virtqueue_disable_cb(struct virtqueue *vq);
bool virtqueue_enable_cb(struct virtqueue *vq);
--
2.32.0.3.g01195cf9f
