diff mbox series

[net-next,v2,17/21] virtio_net: xsk: rx: skip dma unmap when rq is bind with AF_XDP

Message ID 20231107031227.100015-18-xuanzhuo@linux.alibaba.com (mailing list archive)
State Deferred
Delegated to: Netdev Maintainers
Headers show
Series virtio-net: support AF_XDP zero copy | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net-next, async
netdev/apply fail Patch does not apply to net-next

Commit Message

Xuan Zhuo Nov. 7, 2023, 3:12 a.m. UTC 
When rq is bound with AF_XDP, the buffer dma is managed
by the AF_XDP APIs. So the buffer got from the virtio core should
skip the dma unmap operation.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/net/virtio/main.c       | 8 +++++---
 drivers/net/virtio/virtio_net.h | 3 +++
 drivers/net/virtio/xsk.c        | 1 +
 3 files changed, 9 insertions(+), 3 deletions(-)

Comments

Michael S. Tsirkin Nov. 9, 2023, 8:15 a.m. UTC | #1 
On Tue, Nov 07, 2023 at 11:12:23AM +0800, Xuan Zhuo wrote:
> When rq is bound with AF_XDP, the buffer dma is managed
> by the AF_XDP APIs. So the buffer got from the virtio core should
> skip the dma unmap operation.
> 
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>


I don't get it - is this like a bugfix?
And why do we need our own flag and checks?
Doesn't virtio core DTRT?

> ---
>  drivers/net/virtio/main.c       | 8 +++++---
>  drivers/net/virtio/virtio_net.h | 3 +++
>  drivers/net/virtio/xsk.c        | 1 +
>  3 files changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c
> index 15943a22e17d..a318b2533b94 100644
> --- a/drivers/net/virtio/main.c
> +++ b/drivers/net/virtio/main.c
> @@ -430,7 +430,7 @@ static void *virtnet_rq_get_buf(struct virtnet_rq *rq, u32 *len, void **ctx)
>  	void *buf;
>  
>  	buf = virtqueue_get_buf_ctx(rq->vq, len, ctx);
> -	if (buf && rq->do_dma)
> +	if (buf && rq->do_dma_unmap)
>  		virtnet_rq_unmap(rq, buf, *len);
>  
>  	return buf;
> @@ -561,8 +561,10 @@ static void virtnet_set_premapped(struct virtnet_info *vi)
>  
>  		/* disable for big mode */
>  		if (vi->mergeable_rx_bufs || !vi->big_packets) {
> -			if (!virtqueue_set_dma_premapped(vi->rq[i].vq))
> +			if (!virtqueue_set_dma_premapped(vi->rq[i].vq)) {
>  				vi->rq[i].do_dma = true;
> +				vi->rq[i].do_dma_unmap = true;
> +			}
>  		}
>  	}
>  }
> @@ -3944,7 +3946,7 @@ void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf)
>  
>  	rq = &vi->rq[i];
>  
> -	if (rq->do_dma)
> +	if (rq->do_dma_unmap)
>  		virtnet_rq_unmap(rq, buf, 0);
>  
>  	virtnet_rq_free_buf(vi, rq, buf);
> diff --git a/drivers/net/virtio/virtio_net.h b/drivers/net/virtio/virtio_net.h
> index 1242785e311e..2005d0cd22e2 100644
> --- a/drivers/net/virtio/virtio_net.h
> +++ b/drivers/net/virtio/virtio_net.h
> @@ -135,6 +135,9 @@ struct virtnet_rq {
>  	/* Do dma by self */
>  	bool do_dma;
>  
> +	/* Do dma unmap after getting buf from virtio core. */
> +	bool do_dma_unmap;
> +
>  	struct {
>  		struct xsk_buff_pool *pool;
>  
> diff --git a/drivers/net/virtio/xsk.c b/drivers/net/virtio/xsk.c
> index e737c3353212..b09c473c29fb 100644
> --- a/drivers/net/virtio/xsk.c
> +++ b/drivers/net/virtio/xsk.c
> @@ -210,6 +210,7 @@ static int virtnet_rq_bind_xsk_pool(struct virtnet_info *vi, struct virtnet_rq *
>  		xdp_rxq_info_unreg(&rq->xsk.xdp_rxq);
>  
>  	rq->xsk.pool = pool;
> +	rq->do_dma_unmap = !pool;
>  
>  	virtnet_rx_resume(vi, rq);
>  
> -- 
> 2.32.0.3.g01195cf9f
Xuan Zhuo Nov. 9, 2023, 11:10 a.m. UTC | #2 
On Thu, 9 Nov 2023 03:15:03 -0500, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> On Tue, Nov 07, 2023 at 11:12:23AM +0800, Xuan Zhuo wrote:
> > When rq is bound with AF_XDP, the buffer dma is managed
> > by the AF_XDP APIs. So the buffer got from the virtio core should
> > skip the dma unmap operation.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
>
>
> I don't get it - is this like a bugfix?

I want focus on this. So let it as an independent commit.

> And why do we need our own flag and checks?
> Doesn't virtio core DTRT?


struct vring_virtqueue {
	[....]

	/* Do DMA mapping by driver */
	bool premapped;

We can not.

So I add own flag.

Thanks.


>
> > ---
> >  drivers/net/virtio/main.c       | 8 +++++---
> >  drivers/net/virtio/virtio_net.h | 3 +++
> >  drivers/net/virtio/xsk.c        | 1 +
> >  3 files changed, 9 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c
> > index 15943a22e17d..a318b2533b94 100644
> > --- a/drivers/net/virtio/main.c
> > +++ b/drivers/net/virtio/main.c
> > @@ -430,7 +430,7 @@ static void *virtnet_rq_get_buf(struct virtnet_rq *rq, u32 *len, void **ctx)
> >  	void *buf;
> >
> >  	buf = virtqueue_get_buf_ctx(rq->vq, len, ctx);
> > -	if (buf && rq->do_dma)
> > +	if (buf && rq->do_dma_unmap)
> >  		virtnet_rq_unmap(rq, buf, *len);
> >
> >  	return buf;
> > @@ -561,8 +561,10 @@ static void virtnet_set_premapped(struct virtnet_info *vi)
> >
> >  		/* disable for big mode */
> >  		if (vi->mergeable_rx_bufs || !vi->big_packets) {
> > -			if (!virtqueue_set_dma_premapped(vi->rq[i].vq))
> > +			if (!virtqueue_set_dma_premapped(vi->rq[i].vq)) {
> >  				vi->rq[i].do_dma = true;
> > +				vi->rq[i].do_dma_unmap = true;
> > +			}
> >  		}
> >  	}
> >  }
> > @@ -3944,7 +3946,7 @@ void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf)
> >
> >  	rq = &vi->rq[i];
> >
> > -	if (rq->do_dma)
> > +	if (rq->do_dma_unmap)
> >  		virtnet_rq_unmap(rq, buf, 0);
> >
> >  	virtnet_rq_free_buf(vi, rq, buf);
> > diff --git a/drivers/net/virtio/virtio_net.h b/drivers/net/virtio/virtio_net.h
> > index 1242785e311e..2005d0cd22e2 100644
> > --- a/drivers/net/virtio/virtio_net.h
> > +++ b/drivers/net/virtio/virtio_net.h
> > @@ -135,6 +135,9 @@ struct virtnet_rq {
> >  	/* Do dma by self */
> >  	bool do_dma;
> >
> > +	/* Do dma unmap after getting buf from virtio core. */
> > +	bool do_dma_unmap;
> > +
> >  	struct {
> >  		struct xsk_buff_pool *pool;
> >
> > diff --git a/drivers/net/virtio/xsk.c b/drivers/net/virtio/xsk.c
> > index e737c3353212..b09c473c29fb 100644
> > --- a/drivers/net/virtio/xsk.c
> > +++ b/drivers/net/virtio/xsk.c
> > @@ -210,6 +210,7 @@ static int virtnet_rq_bind_xsk_pool(struct virtnet_info *vi, struct virtnet_rq *
> >  		xdp_rxq_info_unreg(&rq->xsk.xdp_rxq);
> >
> >  	rq->xsk.pool = pool;
> > +	rq->do_dma_unmap = !pool;
> >
> >  	virtnet_rx_resume(vi, rq);
> >
> > --
> > 2.32.0.3.g01195cf9f
>
>
Michael S. Tsirkin Nov. 9, 2023, noon UTC | #3 
On Thu, Nov 09, 2023 at 07:10:02PM +0800, Xuan Zhuo wrote:
> On Thu, 9 Nov 2023 03:15:03 -0500, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> > On Tue, Nov 07, 2023 at 11:12:23AM +0800, Xuan Zhuo wrote:
> > > When rq is bound with AF_XDP, the buffer dma is managed
> > > by the AF_XDP APIs. So the buffer got from the virtio core should
> > > skip the dma unmap operation.
> > >
> > > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> >
> >
> > I don't get it - is this like a bugfix?
> 
> I want focus on this. So let it as an independent commit.
> 
> > And why do we need our own flag and checks?
> > Doesn't virtio core DTRT?
> 
> 
> struct vring_virtqueue {
> 	[....]
> 
> 	/* Do DMA mapping by driver */
> 	bool premapped;
> 
> We can not.
> 
> So I add own flag.
> 
> Thanks.

Still don't get it. Why not check the premapped flag?

> 
> >
> > > ---
> > >  drivers/net/virtio/main.c       | 8 +++++---
> > >  drivers/net/virtio/virtio_net.h | 3 +++
> > >  drivers/net/virtio/xsk.c        | 1 +
> > >  3 files changed, 9 insertions(+), 3 deletions(-)
> > >
> > > diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c
> > > index 15943a22e17d..a318b2533b94 100644
> > > --- a/drivers/net/virtio/main.c
> > > +++ b/drivers/net/virtio/main.c
> > > @@ -430,7 +430,7 @@ static void *virtnet_rq_get_buf(struct virtnet_rq *rq, u32 *len, void **ctx)
> > >  	void *buf;
> > >
> > >  	buf = virtqueue_get_buf_ctx(rq->vq, len, ctx);
> > > -	if (buf && rq->do_dma)
> > > +	if (buf && rq->do_dma_unmap)
> > >  		virtnet_rq_unmap(rq, buf, *len);
> > >
> > >  	return buf;
> > > @@ -561,8 +561,10 @@ static void virtnet_set_premapped(struct virtnet_info *vi)
> > >
> > >  		/* disable for big mode */
> > >  		if (vi->mergeable_rx_bufs || !vi->big_packets) {
> > > -			if (!virtqueue_set_dma_premapped(vi->rq[i].vq))
> > > +			if (!virtqueue_set_dma_premapped(vi->rq[i].vq)) {
> > >  				vi->rq[i].do_dma = true;
> > > +				vi->rq[i].do_dma_unmap = true;
> > > +			}
> > >  		}
> > >  	}
> > >  }
> > > @@ -3944,7 +3946,7 @@ void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf)
> > >
> > >  	rq = &vi->rq[i];
> > >
> > > -	if (rq->do_dma)
> > > +	if (rq->do_dma_unmap)
> > >  		virtnet_rq_unmap(rq, buf, 0);
> > >
> > >  	virtnet_rq_free_buf(vi, rq, buf);
> > > diff --git a/drivers/net/virtio/virtio_net.h b/drivers/net/virtio/virtio_net.h
> > > index 1242785e311e..2005d0cd22e2 100644
> > > --- a/drivers/net/virtio/virtio_net.h
> > > +++ b/drivers/net/virtio/virtio_net.h
> > > @@ -135,6 +135,9 @@ struct virtnet_rq {
> > >  	/* Do dma by self */
> > >  	bool do_dma;
> > >
> > > +	/* Do dma unmap after getting buf from virtio core. */
> > > +	bool do_dma_unmap;
> > > +
> > >  	struct {
> > >  		struct xsk_buff_pool *pool;
> > >
> > > diff --git a/drivers/net/virtio/xsk.c b/drivers/net/virtio/xsk.c
> > > index e737c3353212..b09c473c29fb 100644
> > > --- a/drivers/net/virtio/xsk.c
> > > +++ b/drivers/net/virtio/xsk.c
> > > @@ -210,6 +210,7 @@ static int virtnet_rq_bind_xsk_pool(struct virtnet_info *vi, struct virtnet_rq *
> > >  		xdp_rxq_info_unreg(&rq->xsk.xdp_rxq);
> > >
> > >  	rq->xsk.pool = pool;
> > > +	rq->do_dma_unmap = !pool;
> > >
> > >  	virtnet_rx_resume(vi, rq);
> > >
> > > --
> > > 2.32.0.3.g01195cf9f
> >
> >
Xuan Zhuo Nov. 10, 2023, 1:47 a.m. UTC | #4 
On Thu, 9 Nov 2023 07:00:51 -0500, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> On Thu, Nov 09, 2023 at 07:10:02PM +0800, Xuan Zhuo wrote:
> > On Thu, 9 Nov 2023 03:15:03 -0500, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> > > On Tue, Nov 07, 2023 at 11:12:23AM +0800, Xuan Zhuo wrote:
> > > > When rq is bound with AF_XDP, the buffer dma is managed
> > > > by the AF_XDP APIs. So the buffer got from the virtio core should
> > > > skip the dma unmap operation.
> > > >
> > > > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> > >
> > >
> > > I don't get it - is this like a bugfix?
> >
> > I want focus on this. So let it as an independent commit.
> >
> > > And why do we need our own flag and checks?
> > > Doesn't virtio core DTRT?
> >
> >
> > struct vring_virtqueue {
> > 	[....]
> >
> > 	/* Do DMA mapping by driver */
> > 	bool premapped;
> >
> > We can not.
> >
> > So I add own flag.
> >
> > Thanks.
>
> Still don't get it. Why not check the premapped flag?

premapped is in the struct vring_virtqueue.

We can not access it from the driver.


>
> >
> > >
> > > > ---
> > > >  drivers/net/virtio/main.c       | 8 +++++---
> > > >  drivers/net/virtio/virtio_net.h | 3 +++
> > > >  drivers/net/virtio/xsk.c        | 1 +
> > > >  3 files changed, 9 insertions(+), 3 deletions(-)
> > > >
> > > > diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c
> > > > index 15943a22e17d..a318b2533b94 100644
> > > > --- a/drivers/net/virtio/main.c
> > > > +++ b/drivers/net/virtio/main.c
> > > > @@ -430,7 +430,7 @@ static void *virtnet_rq_get_buf(struct virtnet_rq *rq, u32 *len, void **ctx)
> > > >  	void *buf;
> > > >
> > > >  	buf = virtqueue_get_buf_ctx(rq->vq, len, ctx);
> > > > -	if (buf && rq->do_dma)
> > > > +	if (buf && rq->do_dma_unmap)
> > > >  		virtnet_rq_unmap(rq, buf, *len);
> > > >
> > > >  	return buf;
> > > > @@ -561,8 +561,10 @@ static void virtnet_set_premapped(struct virtnet_info *vi)
> > > >
> > > >  		/* disable for big mode */
> > > >  		if (vi->mergeable_rx_bufs || !vi->big_packets) {
> > > > -			if (!virtqueue_set_dma_premapped(vi->rq[i].vq))
> > > > +			if (!virtqueue_set_dma_premapped(vi->rq[i].vq)) {
> > > >  				vi->rq[i].do_dma = true;
> > > > +				vi->rq[i].do_dma_unmap = true;
> > > > +			}
> > > >  		}
> > > >  	}
> > > >  }
> > > > @@ -3944,7 +3946,7 @@ void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf)
> > > >
> > > >  	rq = &vi->rq[i];
> > > >
> > > > -	if (rq->do_dma)
> > > > +	if (rq->do_dma_unmap)
> > > >  		virtnet_rq_unmap(rq, buf, 0);
> > > >
> > > >  	virtnet_rq_free_buf(vi, rq, buf);
> > > > diff --git a/drivers/net/virtio/virtio_net.h b/drivers/net/virtio/virtio_net.h
> > > > index 1242785e311e..2005d0cd22e2 100644
> > > > --- a/drivers/net/virtio/virtio_net.h
> > > > +++ b/drivers/net/virtio/virtio_net.h
> > > > @@ -135,6 +135,9 @@ struct virtnet_rq {
> > > >  	/* Do dma by self */
> > > >  	bool do_dma;
> > > >
> > > > +	/* Do dma unmap after getting buf from virtio core. */
> > > > +	bool do_dma_unmap;
> > > > +
> > > >  	struct {
> > > >  		struct xsk_buff_pool *pool;
> > > >
> > > > diff --git a/drivers/net/virtio/xsk.c b/drivers/net/virtio/xsk.c
> > > > index e737c3353212..b09c473c29fb 100644
> > > > --- a/drivers/net/virtio/xsk.c
> > > > +++ b/drivers/net/virtio/xsk.c
> > > > @@ -210,6 +210,7 @@ static int virtnet_rq_bind_xsk_pool(struct virtnet_info *vi, struct virtnet_rq *
> > > >  		xdp_rxq_info_unreg(&rq->xsk.xdp_rxq);
> > > >
> > > >  	rq->xsk.pool = pool;
> > > > +	rq->do_dma_unmap = !pool;
> > > >
> > > >  	virtnet_rx_resume(vi, rq);
> > > >
> > > > --
> > > > 2.32.0.3.g01195cf9f
> > >
> > >
>
>
Michael S. Tsirkin Nov. 10, 2023, 5:33 a.m. UTC | #5 
On Fri, Nov 10, 2023 at 09:47:16AM +0800, Xuan Zhuo wrote:
> On Thu, 9 Nov 2023 07:00:51 -0500, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> > On Thu, Nov 09, 2023 at 07:10:02PM +0800, Xuan Zhuo wrote:
> > > On Thu, 9 Nov 2023 03:15:03 -0500, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> > > > On Tue, Nov 07, 2023 at 11:12:23AM +0800, Xuan Zhuo wrote:
> > > > > When rq is bound with AF_XDP, the buffer dma is managed
> > > > > by the AF_XDP APIs. So the buffer got from the virtio core should
> > > > > skip the dma unmap operation.
> > > > >
> > > > > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> > > >
> > > >
> > > > I don't get it - is this like a bugfix?
> > >
> > > I want focus on this. So let it as an independent commit.
> > >
> > > > And why do we need our own flag and checks?
> > > > Doesn't virtio core DTRT?
> > >
> > >
> > > struct vring_virtqueue {
> > > 	[....]
> > >
> > > 	/* Do DMA mapping by driver */
> > > 	bool premapped;
> > >
> > > We can not.
> > >
> > > So I add own flag.
> > >
> > > Thanks.
> >
> > Still don't get it. Why not check the premapped flag?
> 
> premapped is in the struct vring_virtqueue.
> 
> We can not access it from the driver.


If it's useful, move it.


> 
> >
> > >
> > > >
> > > > > ---
> > > > >  drivers/net/virtio/main.c       | 8 +++++---
> > > > >  drivers/net/virtio/virtio_net.h | 3 +++
> > > > >  drivers/net/virtio/xsk.c        | 1 +
> > > > >  3 files changed, 9 insertions(+), 3 deletions(-)
> > > > >
> > > > > diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c
> > > > > index 15943a22e17d..a318b2533b94 100644
> > > > > --- a/drivers/net/virtio/main.c
> > > > > +++ b/drivers/net/virtio/main.c
> > > > > @@ -430,7 +430,7 @@ static void *virtnet_rq_get_buf(struct virtnet_rq *rq, u32 *len, void **ctx)
> > > > >  	void *buf;
> > > > >
> > > > >  	buf = virtqueue_get_buf_ctx(rq->vq, len, ctx);
> > > > > -	if (buf && rq->do_dma)
> > > > > +	if (buf && rq->do_dma_unmap)
> > > > >  		virtnet_rq_unmap(rq, buf, *len);
> > > > >
> > > > >  	return buf;
> > > > > @@ -561,8 +561,10 @@ static void virtnet_set_premapped(struct virtnet_info *vi)
> > > > >
> > > > >  		/* disable for big mode */
> > > > >  		if (vi->mergeable_rx_bufs || !vi->big_packets) {
> > > > > -			if (!virtqueue_set_dma_premapped(vi->rq[i].vq))
> > > > > +			if (!virtqueue_set_dma_premapped(vi->rq[i].vq)) {
> > > > >  				vi->rq[i].do_dma = true;
> > > > > +				vi->rq[i].do_dma_unmap = true;
> > > > > +			}
> > > > >  		}
> > > > >  	}
> > > > >  }
> > > > > @@ -3944,7 +3946,7 @@ void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf)
> > > > >
> > > > >  	rq = &vi->rq[i];
> > > > >
> > > > > -	if (rq->do_dma)
> > > > > +	if (rq->do_dma_unmap)
> > > > >  		virtnet_rq_unmap(rq, buf, 0);
> > > > >
> > > > >  	virtnet_rq_free_buf(vi, rq, buf);
> > > > > diff --git a/drivers/net/virtio/virtio_net.h b/drivers/net/virtio/virtio_net.h
> > > > > index 1242785e311e..2005d0cd22e2 100644
> > > > > --- a/drivers/net/virtio/virtio_net.h
> > > > > +++ b/drivers/net/virtio/virtio_net.h
> > > > > @@ -135,6 +135,9 @@ struct virtnet_rq {
> > > > >  	/* Do dma by self */
> > > > >  	bool do_dma;
> > > > >
> > > > > +	/* Do dma unmap after getting buf from virtio core. */
> > > > > +	bool do_dma_unmap;
> > > > > +
> > > > >  	struct {
> > > > >  		struct xsk_buff_pool *pool;
> > > > >
> > > > > diff --git a/drivers/net/virtio/xsk.c b/drivers/net/virtio/xsk.c
> > > > > index e737c3353212..b09c473c29fb 100644
> > > > > --- a/drivers/net/virtio/xsk.c
> > > > > +++ b/drivers/net/virtio/xsk.c
> > > > > @@ -210,6 +210,7 @@ static int virtnet_rq_bind_xsk_pool(struct virtnet_info *vi, struct virtnet_rq *
> > > > >  		xdp_rxq_info_unreg(&rq->xsk.xdp_rxq);
> > > > >
> > > > >  	rq->xsk.pool = pool;
> > > > > +	rq->do_dma_unmap = !pool;
> > > > >
> > > > >  	virtnet_rx_resume(vi, rq);
> > > > >
> > > > > --
> > > > > 2.32.0.3.g01195cf9f
> > > >
> > > >
> >
> >
Xuan Zhuo Nov. 10, 2023, 5:51 a.m. UTC | #6 
On Fri, 10 Nov 2023 00:33:27 -0500, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> On Fri, Nov 10, 2023 at 09:47:16AM +0800, Xuan Zhuo wrote:
> > On Thu, 9 Nov 2023 07:00:51 -0500, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> > > On Thu, Nov 09, 2023 at 07:10:02PM +0800, Xuan Zhuo wrote:
> > > > On Thu, 9 Nov 2023 03:15:03 -0500, "Michael S. Tsirkin" <mst@redhat.com> wrote:
> > > > > On Tue, Nov 07, 2023 at 11:12:23AM +0800, Xuan Zhuo wrote:
> > > > > > When rq is bound with AF_XDP, the buffer dma is managed
> > > > > > by the AF_XDP APIs. So the buffer got from the virtio core should
> > > > > > skip the dma unmap operation.
> > > > > >
> > > > > > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> > > > >
> > > > >
> > > > > I don't get it - is this like a bugfix?
> > > >
> > > > I want focus on this. So let it as an independent commit.
> > > >
> > > > > And why do we need our own flag and checks?
> > > > > Doesn't virtio core DTRT?
> > > >
> > > >
> > > > struct vring_virtqueue {
> > > > 	[....]
> > > >
> > > > 	/* Do DMA mapping by driver */
> > > > 	bool premapped;
> > > >
> > > > We can not.
> > > >
> > > > So I add own flag.
> > > >
> > > > Thanks.
> > >
> > > Still don't get it. Why not check the premapped flag?
> >
> > premapped is in the struct vring_virtqueue.
> >
> > We can not access it from the driver.
>
>
> If it's useful, move it.


We set that by API.

If we expose that to the driver. I worry some driver change it directly.
So I think it's better for the driver to add an own flag.

Thanks.


>
>
> >
> > >
> > > >
> > > > >
> > > > > > ---
> > > > > >  drivers/net/virtio/main.c       | 8 +++++---
> > > > > >  drivers/net/virtio/virtio_net.h | 3 +++
> > > > > >  drivers/net/virtio/xsk.c        | 1 +
> > > > > >  3 files changed, 9 insertions(+), 3 deletions(-)
> > > > > >
> > > > > > diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c
> > > > > > index 15943a22e17d..a318b2533b94 100644
> > > > > > --- a/drivers/net/virtio/main.c
> > > > > > +++ b/drivers/net/virtio/main.c
> > > > > > @@ -430,7 +430,7 @@ static void *virtnet_rq_get_buf(struct virtnet_rq *rq, u32 *len, void **ctx)
> > > > > >  	void *buf;
> > > > > >
> > > > > >  	buf = virtqueue_get_buf_ctx(rq->vq, len, ctx);
> > > > > > -	if (buf && rq->do_dma)
> > > > > > +	if (buf && rq->do_dma_unmap)
> > > > > >  		virtnet_rq_unmap(rq, buf, *len);
> > > > > >
> > > > > >  	return buf;
> > > > > > @@ -561,8 +561,10 @@ static void virtnet_set_premapped(struct virtnet_info *vi)
> > > > > >
> > > > > >  		/* disable for big mode */
> > > > > >  		if (vi->mergeable_rx_bufs || !vi->big_packets) {
> > > > > > -			if (!virtqueue_set_dma_premapped(vi->rq[i].vq))
> > > > > > +			if (!virtqueue_set_dma_premapped(vi->rq[i].vq)) {
> > > > > >  				vi->rq[i].do_dma = true;
> > > > > > +				vi->rq[i].do_dma_unmap = true;
> > > > > > +			}
> > > > > >  		}
> > > > > >  	}
> > > > > >  }
> > > > > > @@ -3944,7 +3946,7 @@ void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf)
> > > > > >
> > > > > >  	rq = &vi->rq[i];
> > > > > >
> > > > > > -	if (rq->do_dma)
> > > > > > +	if (rq->do_dma_unmap)
> > > > > >  		virtnet_rq_unmap(rq, buf, 0);
> > > > > >
> > > > > >  	virtnet_rq_free_buf(vi, rq, buf);
> > > > > > diff --git a/drivers/net/virtio/virtio_net.h b/drivers/net/virtio/virtio_net.h
> > > > > > index 1242785e311e..2005d0cd22e2 100644
> > > > > > --- a/drivers/net/virtio/virtio_net.h
> > > > > > +++ b/drivers/net/virtio/virtio_net.h
> > > > > > @@ -135,6 +135,9 @@ struct virtnet_rq {
> > > > > >  	/* Do dma by self */
> > > > > >  	bool do_dma;
> > > > > >
> > > > > > +	/* Do dma unmap after getting buf from virtio core. */
> > > > > > +	bool do_dma_unmap;
> > > > > > +
> > > > > >  	struct {
> > > > > >  		struct xsk_buff_pool *pool;
> > > > > >
> > > > > > diff --git a/drivers/net/virtio/xsk.c b/drivers/net/virtio/xsk.c
> > > > > > index e737c3353212..b09c473c29fb 100644
> > > > > > --- a/drivers/net/virtio/xsk.c
> > > > > > +++ b/drivers/net/virtio/xsk.c
> > > > > > @@ -210,6 +210,7 @@ static int virtnet_rq_bind_xsk_pool(struct virtnet_info *vi, struct virtnet_rq *
> > > > > >  		xdp_rxq_info_unreg(&rq->xsk.xdp_rxq);
> > > > > >
> > > > > >  	rq->xsk.pool = pool;
> > > > > > +	rq->do_dma_unmap = !pool;
> > > > > >
> > > > > >  	virtnet_rx_resume(vi, rq);
> > > > > >
> > > > > > --
> > > > > > 2.32.0.3.g01195cf9f
> > > > >
> > > > >
> > >
> > >
>
>
diff mbox series

Patch

diff --git a/drivers/net/virtio/main.c b/drivers/net/virtio/main.c
index 15943a22e17d..a318b2533b94 100644
--- a/drivers/net/virtio/main.c
+++ b/drivers/net/virtio/main.c
@@ -430,7 +430,7 @@  static void *virtnet_rq_get_buf(struct virtnet_rq *rq, u32 *len, void **ctx)
 	void *buf;
 
 	buf = virtqueue_get_buf_ctx(rq->vq, len, ctx);
-	if (buf && rq->do_dma)
+	if (buf && rq->do_dma_unmap)
 		virtnet_rq_unmap(rq, buf, *len);
 
 	return buf;
@@ -561,8 +561,10 @@  static void virtnet_set_premapped(struct virtnet_info *vi)
 
 		/* disable for big mode */
 		if (vi->mergeable_rx_bufs || !vi->big_packets) {
-			if (!virtqueue_set_dma_premapped(vi->rq[i].vq))
+			if (!virtqueue_set_dma_premapped(vi->rq[i].vq)) {
 				vi->rq[i].do_dma = true;
+				vi->rq[i].do_dma_unmap = true;
+			}
 		}
 	}
 }
@@ -3944,7 +3946,7 @@  void virtnet_rq_free_unused_buf(struct virtqueue *vq, void *buf)
 
 	rq = &vi->rq[i];
 
-	if (rq->do_dma)
+	if (rq->do_dma_unmap)
 		virtnet_rq_unmap(rq, buf, 0);
 
 	virtnet_rq_free_buf(vi, rq, buf);
diff --git a/drivers/net/virtio/virtio_net.h b/drivers/net/virtio/virtio_net.h
index 1242785e311e..2005d0cd22e2 100644
--- a/drivers/net/virtio/virtio_net.h
+++ b/drivers/net/virtio/virtio_net.h
@@ -135,6 +135,9 @@  struct virtnet_rq {
 	/* Do dma by self */
 	bool do_dma;
 
+	/* Do dma unmap after getting buf from virtio core. */
+	bool do_dma_unmap;
+
 	struct {
 		struct xsk_buff_pool *pool;
 
diff --git a/drivers/net/virtio/xsk.c b/drivers/net/virtio/xsk.c
index e737c3353212..b09c473c29fb 100644
--- a/drivers/net/virtio/xsk.c
+++ b/drivers/net/virtio/xsk.c
@@ -210,6 +210,7 @@  static int virtnet_rq_bind_xsk_pool(struct virtnet_info *vi, struct virtnet_rq *
 		xdp_rxq_info_unreg(&rq->xsk.xdp_rxq);
 
 	rq->xsk.pool = pool;
+	rq->do_dma_unmap = !pool;
 
 	virtnet_rx_resume(vi, rq);