Xuan Zhuo
2023-Feb-14 07:26 UTC
[PATCH vhost 04/10] virtio_ring: split: introduce virtqueue_add_split_premapped()
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 virtio core.
Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
drivers/virtio/virtio_ring.c | 100 +++++++++++++++++++++++++++++++++--
include/linux/virtio.h | 5 ++
2 files changed, 100 insertions(+), 5 deletions(-)
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 47b6f9152f9f..a31155abe101 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;
};
struct vring_desc_state_packed {
@@ -440,7 +441,7 @@ 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;
@@ -457,6 +458,9 @@ 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,
@@ -788,6 +792,47 @@ static inline int virtqueue_add_split(struct virtqueue
*_vq,
return err;
}
+static inline int virtqueue_add_split_premapped(struct virtqueue *_vq,
+ struct scatterlist *sgs[],
+ unsigned int total_sg,
+ unsigned int out_sgs,
+ unsigned int in_sgs,
+ void *data,
+ void *ctx,
+ gfp_t gfp)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+ struct vring_desc *desc;
+ int head;
+ int err;
+
+ START_USE(vq);
+
+ /* check vq state and try to alloc desc for indirect. */
+ err = virtqueue_add_split_prepare(vq, total_sg, out_sgs, data, ctx, gfp,
&desc);
+ if (err)
+ goto end;
+
+ head = vq->free_head;
+ err = virtqueue_add_split_vring(vq, sgs, total_sg, out_sgs, in_sgs, desc);
+ if (err)
+ goto err;
+
+ /* Store token and indirect buffer state. */
+ vq->split.desc_state[head].data = data;
+ vq->split.desc_state[head].indir_desc = desc ? desc : ctx;
+ vq->split.desc_state[head].premapped = true;
+
+ goto end;
+
+err:
+ kfree(desc);
+
+end:
+ END_USE(vq);
+ return err;
+}
+
static bool virtqueue_kick_prepare_split(struct virtqueue *_vq)
{
struct vring_virtqueue *vq = to_vvq(_vq);
@@ -824,20 +869,23 @@ static void detach_buf_split(struct vring_virtqueue *vq,
unsigned int head,
{
unsigned int i, j;
__virtio16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT);
+ bool premapped;
/* Clear data ptr. */
vq->split.desc_state[head].data = NULL;
+ premapped = vq->split.desc_state[head].premapped;
+
/* Put back on free list: unmap first-level descriptors and find end */
i = head;
while (vq->split.vring.desc[i].flags & nextflag) {
- vring_unmap_one_split(vq, i);
+ vring_unmap_one_split(vq, i, premapped);
i = vq->split.desc_extra[i].next;
vq->vq.num_free++;
}
- vring_unmap_one_split(vq, i);
+ vring_unmap_one_split(vq, i, premapped);
vq->split.desc_extra[i].next = vq->free_head;
vq->free_head = head;
@@ -859,8 +907,10 @@ 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));
- for (j = 0; j < len / sizeof(struct vring_desc); j++)
- vring_unmap_one_split_indirect(vq, &indir_desc[j]);
+ if (!premapped) {
+ for (j = 0; j < len / sizeof(struct vring_desc); j++)
+ vring_unmap_one_split_indirect(vq, &indir_desc[j]);
+ }
kfree(indir_desc);
vq->split.desc_state[head].indir_desc = NULL;
@@ -2204,6 +2254,21 @@ static inline int virtqueue_add(struct virtqueue *_vq,
out_sgs, in_sgs, data, ctx, gfp);
}
+static inline int virtqueue_add_premapped(struct virtqueue *_vq,
+ struct scatterlist *sgs[],
+ unsigned int total_sg,
+ unsigned int out_sgs,
+ unsigned int in_sgs,
+ void *data,
+ void *ctx,
+ gfp_t gfp)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ return virtqueue_add_split_premapped(_vq, sgs, total_sg, out_sgs,
+ in_sgs, data, ctx, gfp);
+}
+
/**
* virtqueue_add_sgs - expose buffers to other end
* @_vq: the struct virtqueue we're talking about.
@@ -2261,6 +2326,31 @@ int virtqueue_add_outbuf(struct virtqueue *vq,
}
EXPORT_SYMBOL_GPL(virtqueue_add_outbuf);
+/**
+ * virtqueue_add_outbuf_premapped - expose output buffers to other end
+ * @vq: the struct virtqueue we're talking about.
+ * @sg: scatterlist (must be well-formed and terminated!)
+ * @num: the number of entries in @sg readable by other side
+ * @data: the token identifying the buffer.
+ * @gfp: how to do memory allocations (if necessary).
+ *
+ * Caller must ensure we don't call this with other virtqueue operations
+ * at the same time (except where noted).
+ *
+ * It is required that all addrs have completed DMA operations. And use
+ * sg->dma_address, sg->length to pass addr and length.
+ *
+ * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
+ */
+int virtqueue_add_outbuf_premapped(struct virtqueue *vq,
+ struct scatterlist *sg, unsigned int num,
+ void *data,
+ gfp_t gfp)
+{
+ return virtqueue_add_premapped(vq, &sg, num, 1, 0, data, NULL, gfp);
+}
+EXPORT_SYMBOL_GPL(virtqueue_add_outbuf_premapped);
+
/**
* virtqueue_add_inbuf - expose input buffers to other end
* @vq: the struct virtqueue we're talking about.
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index dcab9c7e8784..d8b472a7dcae 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -43,6 +43,11 @@ int virtqueue_add_outbuf(struct virtqueue *vq,
void *data,
gfp_t gfp);
+int virtqueue_add_outbuf_premapped(struct virtqueue *vq,
+ struct scatterlist *sg, unsigned int num,
+ void *data,
+ gfp_t gfp);
+
int virtqueue_add_inbuf(struct virtqueue *vq,
struct scatterlist sg[], unsigned int num,
void *data,
--
2.32.0.3.g01195cf9f
Jason Wang
2023-Feb-20 05:38 UTC
[PATCH vhost 04/10] virtio_ring: split: introduce virtqueue_add_split_premapped()
On Tue, Feb 14, 2023 at 3:27 PM Xuan Zhuo <xuanzhuo at linux.alibaba.com> wrote:> > 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 virtio core. > > Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com> > --- > drivers/virtio/virtio_ring.c | 100 +++++++++++++++++++++++++++++++++-- > include/linux/virtio.h | 5 ++ > 2 files changed, 100 insertions(+), 5 deletions(-) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index 47b6f9152f9f..a31155abe101 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;Better with a comment. Not native speaker, but "dma_addr" might be better?> }; > > struct vring_desc_state_packed { > @@ -440,7 +441,7 @@ 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; > @@ -457,6 +458,9 @@ 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, > @@ -788,6 +792,47 @@ static inline int virtqueue_add_split(struct virtqueue *_vq, > return err; > } > > +static inline int virtqueue_add_split_premapped(struct virtqueue *_vq, > + struct scatterlist *sgs[], > + unsigned int total_sg, > + unsigned int out_sgs, > + unsigned int in_sgs, > + void *data, > + void *ctx, > + gfp_t gfp) > +{ > + struct vring_virtqueue *vq = to_vvq(_vq); > + struct vring_desc *desc; > + int head; > + int err; > + > + START_USE(vq); > + > + /* check vq state and try to alloc desc for indirect. */ > + err = virtqueue_add_split_prepare(vq, total_sg, out_sgs, data, ctx, gfp, &desc); > + if (err) > + goto end; > + > + head = vq->free_head; > + err = virtqueue_add_split_vring(vq, sgs, total_sg, out_sgs, in_sgs, desc); > + if (err) > + goto err; > + > + /* Store token and indirect buffer state. */ > + vq->split.desc_state[head].data = data; > + vq->split.desc_state[head].indir_desc = desc ? desc : ctx; > + vq->split.desc_state[head].premapped = true;This function duplicates most of the logic of virtqueue_add_split() let's unify it. probably: __virtqueue_add_split(..., bool premapped); virtqueue_add_split() { __virtqueue_add_split(..., false); } virtqueue_add_split_premapped() { __virtqueue_add_split(..., true); } ? And so did for packed (patch 5). Thanks> + > + goto end; > + > +err: > + kfree(desc); > + > +end: > + END_USE(vq); > + return err; > +} > + > static bool virtqueue_kick_prepare_split(struct virtqueue *_vq) > { > struct vring_virtqueue *vq = to_vvq(_vq); > @@ -824,20 +869,23 @@ static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, > { > unsigned int i, j; > __virtio16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT); > + bool premapped; > > /* Clear data ptr. */ > vq->split.desc_state[head].data = NULL; > > + premapped = vq->split.desc_state[head].premapped; > + > /* Put back on free list: unmap first-level descriptors and find end */ > i = head; > > while (vq->split.vring.desc[i].flags & nextflag) { > - vring_unmap_one_split(vq, i); > + vring_unmap_one_split(vq, i, premapped); > i = vq->split.desc_extra[i].next; > vq->vq.num_free++; > } > > - vring_unmap_one_split(vq, i); > + vring_unmap_one_split(vq, i, premapped); > vq->split.desc_extra[i].next = vq->free_head; > vq->free_head = head; > > @@ -859,8 +907,10 @@ 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)); > > - for (j = 0; j < len / sizeof(struct vring_desc); j++) > - vring_unmap_one_split_indirect(vq, &indir_desc[j]); > + if (!premapped) { > + for (j = 0; j < len / sizeof(struct vring_desc); j++) > + vring_unmap_one_split_indirect(vq, &indir_desc[j]); > + } > > kfree(indir_desc); > vq->split.desc_state[head].indir_desc = NULL; > @@ -2204,6 +2254,21 @@ static inline int virtqueue_add(struct virtqueue *_vq, > out_sgs, in_sgs, data, ctx, gfp); > } > > +static inline int virtqueue_add_premapped(struct virtqueue *_vq, > + struct scatterlist *sgs[], > + unsigned int total_sg, > + unsigned int out_sgs, > + unsigned int in_sgs, > + void *data, > + void *ctx, > + gfp_t gfp) > +{ > + struct vring_virtqueue *vq = to_vvq(_vq); > + > + return virtqueue_add_split_premapped(_vq, sgs, total_sg, out_sgs, > + in_sgs, data, ctx, gfp); > +} > + > /** > * virtqueue_add_sgs - expose buffers to other end > * @_vq: the struct virtqueue we're talking about. > @@ -2261,6 +2326,31 @@ int virtqueue_add_outbuf(struct virtqueue *vq, > } > EXPORT_SYMBOL_GPL(virtqueue_add_outbuf); > > +/** > + * virtqueue_add_outbuf_premapped - expose output buffers to other end > + * @vq: the struct virtqueue we're talking about. > + * @sg: scatterlist (must be well-formed and terminated!) > + * @num: the number of entries in @sg readable by other side > + * @data: the token identifying the buffer. > + * @gfp: how to do memory allocations (if necessary). > + * > + * Caller must ensure we don't call this with other virtqueue operations > + * at the same time (except where noted). > + * > + * It is required that all addrs have completed DMA operations. And use > + * sg->dma_address, sg->length to pass addr and length. > + * > + * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO). > + */ > +int virtqueue_add_outbuf_premapped(struct virtqueue *vq, > + struct scatterlist *sg, unsigned int num, > + void *data, > + gfp_t gfp) > +{ > + return virtqueue_add_premapped(vq, &sg, num, 1, 0, data, NULL, gfp); > +} > +EXPORT_SYMBOL_GPL(virtqueue_add_outbuf_premapped); > + > /** > * virtqueue_add_inbuf - expose input buffers to other end > * @vq: the struct virtqueue we're talking about. > diff --git a/include/linux/virtio.h b/include/linux/virtio.h > index dcab9c7e8784..d8b472a7dcae 100644 > --- a/include/linux/virtio.h > +++ b/include/linux/virtio.h > @@ -43,6 +43,11 @@ int virtqueue_add_outbuf(struct virtqueue *vq, > void *data, > gfp_t gfp); > > +int virtqueue_add_outbuf_premapped(struct virtqueue *vq, > + struct scatterlist *sg, unsigned int num, > + void *data, > + gfp_t gfp); > + > int virtqueue_add_inbuf(struct virtqueue *vq, > struct scatterlist sg[], unsigned int num, > void *data, > -- > 2.32.0.3.g01195cf9f >