diff mbox series

[vhost,06/17] virtio_ring: no store dma info when unmap is not needed

Message ID 20240130114224.86536-7-xuanzhuo@linux.alibaba.com (mailing list archive)
State Superseded
Headers show
Series virtio: drivers maintain dma info for premapped vq | expand

Commit Message

Xuan Zhuo Jan. 30, 2024, 11:42 a.m. UTC
As discussed:
http://lore.kernel.org/all/CACGkMEug-=C+VQhkMYSgUKMC==04m7-uem_yC21bgGkKZh845w@mail.gmail.com

When the vq is premapped mode, the driver manages the dma
info is a good way.

So this commit make the virtio core not to store the dma
info and release the memory which is used to store the dma
info.

If the use_dma_api is false, the memory is also not allocated.

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 89 ++++++++++++++++++++++++++++--------
 1 file changed, 70 insertions(+), 19 deletions(-)

Comments

Jason Wang Jan. 31, 2024, 9:12 a.m. UTC | #1
On Tue, Jan 30, 2024 at 7:42 PM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote:
>
> As discussed:
> http://lore.kernel.org/all/CACGkMEug-=C+VQhkMYSgUKMC==04m7-uem_yC21bgGkKZh845w@mail.gmail.com
>
> When the vq is premapped mode, the driver manages the dma
> info is a good way.
>
> So this commit make the virtio core not to store the dma
> info and release the memory which is used to store the dma
> info.
>
> If the use_dma_api is false, the memory is also not allocated.
>
> Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> ---
>  drivers/virtio/virtio_ring.c | 89 ++++++++++++++++++++++++++++--------
>  1 file changed, 70 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index 831667a57429..5bea25167259 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -94,12 +94,15 @@ struct vring_desc_state_packed {
>  };
>
>  struct vring_desc_extra {
> -       dma_addr_t addr;                /* Descriptor DMA addr. */
> -       u32 len;                        /* Descriptor length. */
>         u16 flags;                      /* Descriptor flags. */
>         u16 next;                       /* The next desc state in a list. */
>  };
>
> +struct vring_desc_dma {
> +       dma_addr_t addr;                /* Descriptor DMA addr. */
> +       u32 len;                        /* Descriptor length. */
> +};
> +
>  struct vring_virtqueue_split {
>         /* Actual memory layout for this queue. */
>         struct vring vring;
> @@ -116,6 +119,7 @@ struct vring_virtqueue_split {
>         /* Per-descriptor state. */
>         struct vring_desc_state_split *desc_state;
>         struct vring_desc_extra *desc_extra;
> +       struct vring_desc_dma *desc_dma;
>
>         /* DMA address and size information */
>         dma_addr_t queue_dma_addr;
> @@ -156,6 +160,7 @@ struct vring_virtqueue_packed {
>         /* Per-descriptor state. */
>         struct vring_desc_state_packed *desc_state;
>         struct vring_desc_extra *desc_extra;
> +       struct vring_desc_dma *desc_dma;
>
>         /* DMA address and size information */
>         dma_addr_t ring_dma_addr;
> @@ -472,13 +477,14 @@ static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq,
>                                           unsigned int i)
>  {
>         struct vring_desc_extra *extra = vq->split.desc_extra;
> +       struct vring_desc_dma *dma = vq->split.desc_dma;
>         u16 flags;
>
>         flags = extra[i].flags;
>
>         dma_unmap_page(vring_dma_dev(vq),
> -                      extra[i].addr,
> -                      extra[i].len,
> +                      dma[i].addr,
> +                      dma[i].len,
>                        (flags & VRING_DESC_F_WRITE) ?
>                        DMA_FROM_DEVICE : DMA_TO_DEVICE);
>
> @@ -535,8 +541,11 @@ static inline unsigned int virtqueue_add_desc_split(struct virtqueue *vq,
>                 next = extra[i].next;
>                 desc[i].next = cpu_to_virtio16(vq->vdev, next);
>
> -               extra[i].addr = addr;
> -               extra[i].len = len;
> +               if (vring->split.desc_dma) {
> +                       vring->split.desc_dma[i].addr = addr;
> +                       vring->split.desc_dma[i].len = len;
> +               }
> +
>                 extra[i].flags = flags;
>         } else
>                 next = virtio16_to_cpu(vq->vdev, desc[i].next);
> @@ -1072,16 +1081,26 @@ static void virtqueue_vring_attach_split(struct vring_virtqueue *vq,
>         vq->free_head = 0;
>  }
>
> -static int vring_alloc_state_extra_split(struct vring_virtqueue_split *vring_split)
> +static int vring_alloc_state_extra_split(struct vring_virtqueue_split *vring_split,
> +                                        bool need_unmap)
>  {
>         struct vring_desc_state_split *state;
>         struct vring_desc_extra *extra;
> +       struct vring_desc_dma *dma;
>         u32 num = vring_split->vring.num;
>
>         state = kmalloc_array(num, sizeof(struct vring_desc_state_split), GFP_KERNEL);
>         if (!state)
>                 goto err_state;
>
> +       if (need_unmap) {
> +               dma = kmalloc_array(num, sizeof(struct vring_desc_dma), GFP_KERNEL);
> +               if (!dma)
> +                       goto err_dma;
> +       } else {
> +               dma = NULL;
> +       }
> +
>         extra = vring_alloc_desc_extra(num);
>         if (!extra)
>                 goto err_extra;
> @@ -1090,9 +1109,12 @@ static int vring_alloc_state_extra_split(struct vring_virtqueue_split *vring_spl
>
>         vring_split->desc_state = state;
>         vring_split->desc_extra = extra;
> +       vring_split->desc_dma = dma;
>         return 0;
>
>  err_extra:
> +       kfree(dma);
> +err_dma:
>         kfree(state);
>  err_state:
>         return -ENOMEM;
> @@ -1108,6 +1130,7 @@ static void vring_free_split(struct vring_virtqueue_split *vring_split,
>
>         kfree(vring_split->desc_state);
>         kfree(vring_split->desc_extra);
> +       kfree(vring_split->desc_dma);
>  }
>
>  static int vring_alloc_queue_split(struct vring_virtqueue_split *vring_split,
> @@ -1209,7 +1232,8 @@ static int virtqueue_resize_split(struct virtqueue *_vq, u32 num)
>         if (err)
>                 goto err;
>
> -       err = vring_alloc_state_extra_split(&vring_split);
> +       err = vring_alloc_state_extra_split(&vring_split,
> +                                           vring_need_unmap_buffer(vq));
>         if (err)
>                 goto err_state_extra;
>
> @@ -1245,14 +1269,16 @@ static u16 packed_last_used(u16 last_used_idx)
>
>  /* caller must check vring_need_unmap_buffer() */
>  static void vring_unmap_extra_packed(const struct vring_virtqueue *vq,
> -                                    const struct vring_desc_extra *extra)
> +                                    unsigned int i)
>  {
> +       const struct vring_desc_extra *extra = &vq->packed.desc_extra[i];
> +       const struct vring_desc_dma *dma = &vq->packed.desc_dma[i];
>         u16 flags;
>
>         flags = extra->flags;

I don't think this can be compiled.

Thanks
Xuan Zhuo Feb. 1, 2024, 6:04 a.m. UTC | #2
On Wed, 31 Jan 2024 17:12:29 +0800, Jason Wang <jasowang@redhat.com> wrote:
> On Tue, Jan 30, 2024 at 7:42 PM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote:
> >
> > As discussed:
> > http://lore.kernel.org/all/CACGkMEug-=C+VQhkMYSgUKMC==04m7-uem_yC21bgGkKZh845w@mail.gmail.com
> >
> > When the vq is premapped mode, the driver manages the dma
> > info is a good way.
> >
> > So this commit make the virtio core not to store the dma
> > info and release the memory which is used to store the dma
> > info.
> >
> > If the use_dma_api is false, the memory is also not allocated.
> >
> > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> > ---
> >  drivers/virtio/virtio_ring.c | 89 ++++++++++++++++++++++++++++--------
> >  1 file changed, 70 insertions(+), 19 deletions(-)
> >
> > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> > index 831667a57429..5bea25167259 100644
> > --- a/drivers/virtio/virtio_ring.c
> > +++ b/drivers/virtio/virtio_ring.c
> > @@ -94,12 +94,15 @@ struct vring_desc_state_packed {
> >  };
> >
> >  struct vring_desc_extra {
> > -       dma_addr_t addr;                /* Descriptor DMA addr. */
> > -       u32 len;                        /* Descriptor length. */
> >         u16 flags;                      /* Descriptor flags. */
> >         u16 next;                       /* The next desc state in a list. */
> >  };
> >
> > +struct vring_desc_dma {
> > +       dma_addr_t addr;                /* Descriptor DMA addr. */
> > +       u32 len;                        /* Descriptor length. */
> > +};
> > +
> >  struct vring_virtqueue_split {
> >         /* Actual memory layout for this queue. */
> >         struct vring vring;
> > @@ -116,6 +119,7 @@ struct vring_virtqueue_split {
> >         /* Per-descriptor state. */
> >         struct vring_desc_state_split *desc_state;
> >         struct vring_desc_extra *desc_extra;
> > +       struct vring_desc_dma *desc_dma;
> >
> >         /* DMA address and size information */
> >         dma_addr_t queue_dma_addr;
> > @@ -156,6 +160,7 @@ struct vring_virtqueue_packed {
> >         /* Per-descriptor state. */
> >         struct vring_desc_state_packed *desc_state;
> >         struct vring_desc_extra *desc_extra;
> > +       struct vring_desc_dma *desc_dma;
> >
> >         /* DMA address and size information */
> >         dma_addr_t ring_dma_addr;
> > @@ -472,13 +477,14 @@ static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq,
> >                                           unsigned int i)
> >  {
> >         struct vring_desc_extra *extra = vq->split.desc_extra;
> > +       struct vring_desc_dma *dma = vq->split.desc_dma;
> >         u16 flags;
> >
> >         flags = extra[i].flags;
> >
> >         dma_unmap_page(vring_dma_dev(vq),
> > -                      extra[i].addr,
> > -                      extra[i].len,
> > +                      dma[i].addr,
> > +                      dma[i].len,
> >                        (flags & VRING_DESC_F_WRITE) ?
> >                        DMA_FROM_DEVICE : DMA_TO_DEVICE);
> >
> > @@ -535,8 +541,11 @@ static inline unsigned int virtqueue_add_desc_split(struct virtqueue *vq,
> >                 next = extra[i].next;
> >                 desc[i].next = cpu_to_virtio16(vq->vdev, next);
> >
> > -               extra[i].addr = addr;
> > -               extra[i].len = len;
> > +               if (vring->split.desc_dma) {
> > +                       vring->split.desc_dma[i].addr = addr;
> > +                       vring->split.desc_dma[i].len = len;
> > +               }
> > +
> >                 extra[i].flags = flags;
> >         } else
> >                 next = virtio16_to_cpu(vq->vdev, desc[i].next);
> > @@ -1072,16 +1081,26 @@ static void virtqueue_vring_attach_split(struct vring_virtqueue *vq,
> >         vq->free_head = 0;
> >  }
> >
> > -static int vring_alloc_state_extra_split(struct vring_virtqueue_split *vring_split)
> > +static int vring_alloc_state_extra_split(struct vring_virtqueue_split *vring_split,
> > +                                        bool need_unmap)
> >  {
> >         struct vring_desc_state_split *state;
> >         struct vring_desc_extra *extra;
> > +       struct vring_desc_dma *dma;
> >         u32 num = vring_split->vring.num;
> >
> >         state = kmalloc_array(num, sizeof(struct vring_desc_state_split), GFP_KERNEL);
> >         if (!state)
> >                 goto err_state;
> >
> > +       if (need_unmap) {
> > +               dma = kmalloc_array(num, sizeof(struct vring_desc_dma), GFP_KERNEL);
> > +               if (!dma)
> > +                       goto err_dma;
> > +       } else {
> > +               dma = NULL;
> > +       }
> > +
> >         extra = vring_alloc_desc_extra(num);
> >         if (!extra)
> >                 goto err_extra;
> > @@ -1090,9 +1109,12 @@ static int vring_alloc_state_extra_split(struct vring_virtqueue_split *vring_spl
> >
> >         vring_split->desc_state = state;
> >         vring_split->desc_extra = extra;
> > +       vring_split->desc_dma = dma;
> >         return 0;
> >
> >  err_extra:
> > +       kfree(dma);
> > +err_dma:
> >         kfree(state);
> >  err_state:
> >         return -ENOMEM;
> > @@ -1108,6 +1130,7 @@ static void vring_free_split(struct vring_virtqueue_split *vring_split,
> >
> >         kfree(vring_split->desc_state);
> >         kfree(vring_split->desc_extra);
> > +       kfree(vring_split->desc_dma);
> >  }
> >
> >  static int vring_alloc_queue_split(struct vring_virtqueue_split *vring_split,
> > @@ -1209,7 +1232,8 @@ static int virtqueue_resize_split(struct virtqueue *_vq, u32 num)
> >         if (err)
> >                 goto err;
> >
> > -       err = vring_alloc_state_extra_split(&vring_split);
> > +       err = vring_alloc_state_extra_split(&vring_split,
> > +                                           vring_need_unmap_buffer(vq));
> >         if (err)
> >                 goto err_state_extra;
> >
> > @@ -1245,14 +1269,16 @@ static u16 packed_last_used(u16 last_used_idx)
> >
> >  /* caller must check vring_need_unmap_buffer() */
> >  static void vring_unmap_extra_packed(const struct vring_virtqueue *vq,
> > -                                    const struct vring_desc_extra *extra)
> > +                                    unsigned int i)
> >  {
> > +       const struct vring_desc_extra *extra = &vq->packed.desc_extra[i];
> > +       const struct vring_desc_dma *dma = &vq->packed.desc_dma[i];
> >         u16 flags;
> >
> >         flags = extra->flags;
>
> I don't think this can be compiled.

I do not find any error.
Could you say more?

Thanks.


>
> Thanks
>
Jason Wang Feb. 2, 2024, 3:04 a.m. UTC | #3
On Thu, Feb 1, 2024 at 2:05 PM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote:
>
> On Wed, 31 Jan 2024 17:12:29 +0800, Jason Wang <jasowang@redhat.com> wrote:
> > On Tue, Jan 30, 2024 at 7:42 PM Xuan Zhuo <xuanzhuo@linux.alibaba.com> wrote:
> > >
> > > As discussed:
> > > http://lore.kernel.org/all/CACGkMEug-=C+VQhkMYSgUKMC==04m7-uem_yC21bgGkKZh845w@mail.gmail.com
> > >
> > > When the vq is premapped mode, the driver manages the dma
> > > info is a good way.
> > >
> > > So this commit make the virtio core not to store the dma
> > > info and release the memory which is used to store the dma
> > > info.
> > >
> > > If the use_dma_api is false, the memory is also not allocated.
> > >
> > > Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
> > > ---

[...]

> > >
> > > @@ -1245,14 +1269,16 @@ static u16 packed_last_used(u16 last_used_idx)
> > >
> > >  /* caller must check vring_need_unmap_buffer() */
> > >  static void vring_unmap_extra_packed(const struct vring_virtqueue *vq,
> > > -                                    const struct vring_desc_extra *extra)
> > > +                                    unsigned int i)
> > >  {
> > > +       const struct vring_desc_extra *extra = &vq->packed.desc_extra[i];
> > > +       const struct vring_desc_dma *dma = &vq->packed.desc_dma[i];
> > >         u16 flags;
> > >
> > >         flags = extra->flags;
> >
> > I don't think this can be compiled.
>
> I do not find any error.
> Could you say more?

Sorry, I misread the code.

It should be fine.

Thanks

>
> Thanks.
>
>
> >
> > Thanks
> >
>
diff mbox series

Patch

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 831667a57429..5bea25167259 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -94,12 +94,15 @@  struct vring_desc_state_packed {
 };
 
 struct vring_desc_extra {
-	dma_addr_t addr;		/* Descriptor DMA addr. */
-	u32 len;			/* Descriptor length. */
 	u16 flags;			/* Descriptor flags. */
 	u16 next;			/* The next desc state in a list. */
 };
 
+struct vring_desc_dma {
+	dma_addr_t addr;		/* Descriptor DMA addr. */
+	u32 len;			/* Descriptor length. */
+};
+
 struct vring_virtqueue_split {
 	/* Actual memory layout for this queue. */
 	struct vring vring;
@@ -116,6 +119,7 @@  struct vring_virtqueue_split {
 	/* Per-descriptor state. */
 	struct vring_desc_state_split *desc_state;
 	struct vring_desc_extra *desc_extra;
+	struct vring_desc_dma *desc_dma;
 
 	/* DMA address and size information */
 	dma_addr_t queue_dma_addr;
@@ -156,6 +160,7 @@  struct vring_virtqueue_packed {
 	/* Per-descriptor state. */
 	struct vring_desc_state_packed *desc_state;
 	struct vring_desc_extra *desc_extra;
+	struct vring_desc_dma *desc_dma;
 
 	/* DMA address and size information */
 	dma_addr_t ring_dma_addr;
@@ -472,13 +477,14 @@  static unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq,
 					  unsigned int i)
 {
 	struct vring_desc_extra *extra = vq->split.desc_extra;
+	struct vring_desc_dma *dma = vq->split.desc_dma;
 	u16 flags;
 
 	flags = extra[i].flags;
 
 	dma_unmap_page(vring_dma_dev(vq),
-		       extra[i].addr,
-		       extra[i].len,
+		       dma[i].addr,
+		       dma[i].len,
 		       (flags & VRING_DESC_F_WRITE) ?
 		       DMA_FROM_DEVICE : DMA_TO_DEVICE);
 
@@ -535,8 +541,11 @@  static inline unsigned int virtqueue_add_desc_split(struct virtqueue *vq,
 		next = extra[i].next;
 		desc[i].next = cpu_to_virtio16(vq->vdev, next);
 
-		extra[i].addr = addr;
-		extra[i].len = len;
+		if (vring->split.desc_dma) {
+			vring->split.desc_dma[i].addr = addr;
+			vring->split.desc_dma[i].len = len;
+		}
+
 		extra[i].flags = flags;
 	} else
 		next = virtio16_to_cpu(vq->vdev, desc[i].next);
@@ -1072,16 +1081,26 @@  static void virtqueue_vring_attach_split(struct vring_virtqueue *vq,
 	vq->free_head = 0;
 }
 
-static int vring_alloc_state_extra_split(struct vring_virtqueue_split *vring_split)
+static int vring_alloc_state_extra_split(struct vring_virtqueue_split *vring_split,
+					 bool need_unmap)
 {
 	struct vring_desc_state_split *state;
 	struct vring_desc_extra *extra;
+	struct vring_desc_dma *dma;
 	u32 num = vring_split->vring.num;
 
 	state = kmalloc_array(num, sizeof(struct vring_desc_state_split), GFP_KERNEL);
 	if (!state)
 		goto err_state;
 
+	if (need_unmap) {
+		dma = kmalloc_array(num, sizeof(struct vring_desc_dma), GFP_KERNEL);
+		if (!dma)
+			goto err_dma;
+	} else {
+		dma = NULL;
+	}
+
 	extra = vring_alloc_desc_extra(num);
 	if (!extra)
 		goto err_extra;
@@ -1090,9 +1109,12 @@  static int vring_alloc_state_extra_split(struct vring_virtqueue_split *vring_spl
 
 	vring_split->desc_state = state;
 	vring_split->desc_extra = extra;
+	vring_split->desc_dma = dma;
 	return 0;
 
 err_extra:
+	kfree(dma);
+err_dma:
 	kfree(state);
 err_state:
 	return -ENOMEM;
@@ -1108,6 +1130,7 @@  static void vring_free_split(struct vring_virtqueue_split *vring_split,
 
 	kfree(vring_split->desc_state);
 	kfree(vring_split->desc_extra);
+	kfree(vring_split->desc_dma);
 }
 
 static int vring_alloc_queue_split(struct vring_virtqueue_split *vring_split,
@@ -1209,7 +1232,8 @@  static int virtqueue_resize_split(struct virtqueue *_vq, u32 num)
 	if (err)
 		goto err;
 
-	err = vring_alloc_state_extra_split(&vring_split);
+	err = vring_alloc_state_extra_split(&vring_split,
+					    vring_need_unmap_buffer(vq));
 	if (err)
 		goto err_state_extra;
 
@@ -1245,14 +1269,16 @@  static u16 packed_last_used(u16 last_used_idx)
 
 /* caller must check vring_need_unmap_buffer() */
 static void vring_unmap_extra_packed(const struct vring_virtqueue *vq,
-				     const struct vring_desc_extra *extra)
+				     unsigned int i)
 {
+	const struct vring_desc_extra *extra = &vq->packed.desc_extra[i];
+	const struct vring_desc_dma *dma = &vq->packed.desc_dma[i];
 	u16 flags;
 
 	flags = extra->flags;
 
 	dma_unmap_page(vring_dma_dev(vq),
-		       extra->addr, extra->len,
+		       dma->addr, dma->len,
 		       (flags & VRING_DESC_F_WRITE) ?
 		       DMA_FROM_DEVICE : DMA_TO_DEVICE);
 }
@@ -1499,8 +1525,8 @@  static inline int virtqueue_add_packed(struct virtqueue *_vq,
 			desc[i].id = cpu_to_le16(id);
 
 			if (unlikely(vring_need_unmap_buffer(vq))) {
-				vq->packed.desc_extra[curr].addr = addr;
-				vq->packed.desc_extra[curr].len = sg->length;
+				vq->packed.desc_dma[curr].addr = addr;
+				vq->packed.desc_dma[curr].len = sg->length;
 			}
 
 			vq->packed.desc_extra[curr].flags = le16_to_cpu(flags);
@@ -1559,7 +1585,7 @@  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, curr);
 		curr = vq->packed.desc_extra[curr].next;
 		i++;
 		if (i >= vq->packed.vring.num)
@@ -1640,8 +1666,7 @@  static void detach_buf_packed(struct vring_virtqueue *vq,
 		if (vring_need_unmap_buffer(vq)) {
 			curr = id;
 			for (i = 0; i < state->num; i++) {
-				vring_unmap_extra_packed(vq,
-							 &vq->packed.desc_extra[curr]);
+				vring_unmap_extra_packed(vq, curr);
 				curr = vq->packed.desc_extra[curr].next;
 			}
 		}
@@ -1955,6 +1980,7 @@  static void vring_free_packed(struct vring_virtqueue_packed *vring_packed,
 
 	kfree(vring_packed->desc_state);
 	kfree(vring_packed->desc_extra);
+	kfree(vring_packed->desc_dma);
 }
 
 static int vring_alloc_queue_packed(struct vring_virtqueue_packed *vring_packed,
@@ -2011,10 +2037,12 @@  static int vring_alloc_queue_packed(struct vring_virtqueue_packed *vring_packed,
 	return -ENOMEM;
 }
 
-static int vring_alloc_state_extra_packed(struct vring_virtqueue_packed *vring_packed)
+static int vring_alloc_state_extra_packed(struct vring_virtqueue_packed *vring_packed,
+					  bool need_unmap)
 {
 	struct vring_desc_state_packed *state;
 	struct vring_desc_extra *extra;
+	struct vring_desc_dma *dma;
 	u32 num = vring_packed->vring.num;
 
 	state = kmalloc_array(num, sizeof(struct vring_desc_state_packed), GFP_KERNEL);
@@ -2023,6 +2051,14 @@  static int vring_alloc_state_extra_packed(struct vring_virtqueue_packed *vring_p
 
 	memset(state, 0, num * sizeof(struct vring_desc_state_packed));
 
+	if (need_unmap) {
+		dma = kmalloc_array(num, sizeof(struct vring_desc_dma), GFP_KERNEL);
+		if (!dma)
+			goto err_desc_dma;
+	} else {
+		dma = NULL;
+	}
+
 	extra = vring_alloc_desc_extra(num);
 	if (!extra)
 		goto err_desc_extra;
@@ -2033,6 +2069,8 @@  static int vring_alloc_state_extra_packed(struct vring_virtqueue_packed *vring_p
 	return 0;
 
 err_desc_extra:
+	kfree(dma);
+err_desc_dma:
 	kfree(state);
 err_desc_state:
 	return -ENOMEM;
@@ -2124,7 +2162,8 @@  static struct virtqueue *vring_create_virtqueue_packed(
 	if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
 		vq->weak_barriers = false;
 
-	err = vring_alloc_state_extra_packed(&vring_packed);
+	err = vring_alloc_state_extra_packed(&vring_packed,
+					     vring_need_unmap_buffer(vq));
 	if (err)
 		goto err_state_extra;
 
@@ -2156,7 +2195,8 @@  static int virtqueue_resize_packed(struct virtqueue *_vq, u32 num)
 	if (vring_alloc_queue_packed(&vring_packed, vdev, num, vring_dma_dev(vq)))
 		goto err_ring;
 
-	err = vring_alloc_state_extra_packed(&vring_packed);
+	err = vring_alloc_state_extra_packed(&vring_packed,
+					     vring_need_unmap_buffer(vq));
 	if (err)
 		goto err_state_extra;
 
@@ -2668,7 +2708,8 @@  static struct virtqueue *__vring_new_virtqueue(unsigned int index,
 	if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
 		vq->weak_barriers = false;
 
-	err = vring_alloc_state_extra_split(vring_split);
+	err = vring_alloc_state_extra_split(vring_split,
+					    vring_need_unmap_buffer(vq));
 	if (err) {
 		kfree(vq);
 		return NULL;
@@ -2828,6 +2869,14 @@  int virtqueue_set_dma_premapped(struct virtqueue *_vq)
 
 	vq->premapped = true;
 
+	if (vq->packed_ring) {
+		kfree(vq->packed.desc_dma);
+		vq->packed.desc_dma = NULL;
+	} else {
+		kfree(vq->split.desc_dma);
+		vq->split.desc_dma = NULL;
+	}
+
 	END_USE(vq);
 
 	return 0;
@@ -2917,6 +2966,7 @@  static void vring_free(struct virtqueue *_vq)
 
 			kfree(vq->packed.desc_state);
 			kfree(vq->packed.desc_extra);
+			kfree(vq->packed.desc_dma);
 		} else {
 			vring_free_queue(vq->vq.vdev,
 					 vq->split.queue_size_in_bytes,
@@ -2928,6 +2978,7 @@  static void vring_free(struct virtqueue *_vq)
 	if (!vq->packed_ring) {
 		kfree(vq->split.desc_state);
 		kfree(vq->split.desc_extra);
+		kfree(vq->split.desc_dma);
 	}
 }