[09/10] virtio/s390: use DMA memory for ccw I/O and classic notifiers

Commit Message

Halil Pasic April 26, 2019, 6:32 p.m. UTC

Before virtio-ccw could get away with not using DMA API for the pieces of
memory it does ccw I/O with. With protected virtualization this has to
change, since the hypervisor needs to read and sometimes also write these
pieces of memory.

The hypervisor is supposed to poke the classic notifiers, if these are
used, out of band with regards to ccw I/O. So these need to be allocated
as DMA memory (which is shared memory for protected virtualization
guests).

Let us factor out everything from struct virtio_ccw_device that needs to
be DMA memory in a satellite that is allocated as such.

Note: The control blocks of I/O instructions do not need to be shared.
These are marshalled by the ultravisor.

Signed-off-by: Halil Pasic <[e-mail]>
---
 drivers/s390/virtio/virtio_ccw.c | 177 +++++++++++++++++++++------------------
 1 file changed, 96 insertions(+), 81 deletions(-)

Comments

Pierre Morel May 8, 2019, 2:46 p.m. UTC | #1

On 26/04/2019 20:32, Halil Pasic wrote:
> Before virtio-ccw could get away with not using DMA API for the pieces of
> memory it does ccw I/O with. With protected virtualization this has to
> change, since the hypervisor needs to read and sometimes also write these
> pieces of memory.
> 
> The hypervisor is supposed to poke the classic notifiers, if these are
> used, out of band with regards to ccw I/O. So these need to be allocated
> as DMA memory (which is shared memory for protected virtualization
> guests).
> 
> Let us factor out everything from struct virtio_ccw_device that needs to
> be DMA memory in a satellite that is allocated as such.
> 
> Note: The control blocks of I/O instructions do not need to be shared.
> These are marshalled by the ultravisor.
> 
> Signed-off-by: Halil Pasic <[e-mail]>
> ---
>   drivers/s390/virtio/virtio_ccw.c | 177 +++++++++++++++++++++------------------
>   1 file changed, 96 insertions(+), 81 deletions(-)
> 
> diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
> index 1f3e7d56924f..613b18001a0c 100644
> --- a/drivers/s390/virtio/virtio_ccw.c
> +++ b/drivers/s390/virtio/virtio_ccw.c
> @@ -46,9 +46,15 @@ struct vq_config_block {
>   #define VIRTIO_CCW_CONFIG_SIZE 0x100
>   /* same as PCI config space size, should be enough for all drivers */
>   
> +struct vcdev_dma_area {
> +	unsigned long indicators;
> +	unsigned long indicators2;
> +	struct vq_config_block config_block;
> +	__u8 status;
> +};
> +
>   struct virtio_ccw_device {
>   	struct virtio_device vdev;
> -	__u8 *status;
>   	__u8 config[VIRTIO_CCW_CONFIG_SIZE];
>   	struct ccw_device *cdev;
>   	__u32 curr_io;
> @@ -58,24 +64,22 @@ struct virtio_ccw_device {
>   	spinlock_t lock;
>   	struct mutex io_lock; /* Serializes I/O requests */
>   	struct list_head virtqueues;
> -	unsigned long indicators;
> -	unsigned long indicators2;
> -	struct vq_config_block *config_block;
>   	bool is_thinint;
>   	bool going_away;
>   	bool device_lost;
>   	unsigned int config_ready;
>   	void *airq_info;
> +	struct vcdev_dma_area *dma_area;
>   };
>   
>   static inline unsigned long *indicators(struct virtio_ccw_device *vcdev)
>   {
> -	return &vcdev->indicators;
> +	return &vcdev->dma_area->indicators;
>   }
>   
>   static inline unsigned long *indicators2(struct virtio_ccw_device *vcdev)
>   {
> -	return &vcdev->indicators2;
> +	return &vcdev->dma_area->indicators2;
>   }
>   
>   struct vq_info_block_legacy {
> @@ -176,6 +180,22 @@ static struct virtio_ccw_device *to_vc_device(struct virtio_device *vdev)
>   	return container_of(vdev, struct virtio_ccw_device, vdev);
>   }
>   
> +static inline void *__vc_dma_alloc(struct virtio_device *vdev, size_t size)
> +{
> +	return ccw_device_dma_zalloc(to_vc_device(vdev)->cdev, size);
> +}
> +
> +static inline void __vc_dma_free(struct virtio_device *vdev, size_t size,
> +				 void *cpu_addr)
> +{
> +	return ccw_device_dma_free(to_vc_device(vdev)->cdev, cpu_addr, size);
> +}
> +
> +#define vc_dma_alloc_struct(vdev, ptr) \
> +	({ptr = __vc_dma_alloc(vdev, sizeof(*(ptr))); })
> +#define vc_dma_free_struct(vdev, ptr) \
> +	__vc_dma_free(vdev, sizeof(*(ptr)), (ptr))
> +
>   static void drop_airq_indicator(struct virtqueue *vq, struct airq_info *info)
>   {
>   	unsigned long i, flags;
> @@ -335,8 +355,7 @@ static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev,
>   	struct airq_info *airq_info = vcdev->airq_info;
>   
>   	if (vcdev->is_thinint) {
> -		thinint_area = kzalloc(sizeof(*thinint_area),
> -				       GFP_DMA | GFP_KERNEL);
> +		vc_dma_alloc_struct(&vcdev->vdev, thinint_area);
>   		if (!thinint_area)
>   			return;
>   		thinint_area->summary_indicator =
> @@ -347,8 +366,8 @@ static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev,
>   		ccw->cda = (__u32)(unsigned long) thinint_area;
>   	} else {
>   		/* payload is the address of the indicators */
> -		indicatorp = kmalloc(sizeof(indicators(vcdev)),
> -				     GFP_DMA | GFP_KERNEL);
> +		indicatorp = __vc_dma_alloc(&vcdev->vdev,
> +					   sizeof(indicators(vcdev)));

should be sizeof(long) ?

This is a recurrent error, but it is not an issue because the size of
the indicators is unsigned long as the size of the pointer.

Regards,
Pierre

Pierre Morel May 9, 2019, 1:30 p.m. UTC | #2

On 08/05/2019 16:46, Pierre Morel wrote:
> On 26/04/2019 20:32, Halil Pasic wrote:
>> Before virtio-ccw could get away with not using DMA API for the pieces of
>> memory it does ccw I/O with. With protected virtualization this has to
>> change, since the hypervisor needs to read and sometimes also write these
>> pieces of memory.
>>
>> The hypervisor is supposed to poke the classic notifiers, if these are
>> used, out of band with regards to ccw I/O. So these need to be allocated
>> as DMA memory (which is shared memory for protected virtualization
>> guests).
>>
>> Let us factor out everything from struct virtio_ccw_device that needs to
>> be DMA memory in a satellite that is allocated as such.
>>
...
>> +                       sizeof(indicators(vcdev)));
> 
> should be sizeof(long) ?
> 
> This is a recurrent error, but it is not an issue because the size of
> the indicators is unsigned long as the size of the pointer.
> 
> Regards,
> Pierre
> 

Here too, with the problem of the indicator size handled:
Reviewed-by: Pierre Morel<[e-mail]>

Halil Pasic May 9, 2019, 6:30 p.m. UTC | #3

On Thu, 9 May 2019 15:30:08 +0200
Pierre Morel <[e-mail]> wrote:

> On 08/05/2019 16:46, Pierre Morel wrote:
> > On 26/04/2019 20:32, Halil Pasic wrote:
> >> Before virtio-ccw could get away with not using DMA API for the pieces of
> >> memory it does ccw I/O with. With protected virtualization this has to
> >> change, since the hypervisor needs to read and sometimes also write these
> >> pieces of memory.
> >>
> >> The hypervisor is supposed to poke the classic notifiers, if these are
> >> used, out of band with regards to ccw I/O. So these need to be allocated
> >> as DMA memory (which is shared memory for protected virtualization
> >> guests).
> >>
> >> Let us factor out everything from struct virtio_ccw_device that needs to
> >> be DMA memory in a satellite that is allocated as such.
> >>
> ...
> >> +                       sizeof(indicators(vcdev)));
> > 
> > should be sizeof(long) ?

If something different then sizeof(u64) IMHO.
> > 
> > This is a recurrent error, but it is not an issue because the size of
> > the indicators is unsigned long as the size of the pointer.

I don't think there is an error, let alone a recurrent one.

> > 
> > Regards,
> > Pierre
> > 
> 
> Here too, with the problem of the indicator size handled:

I've laid out my view in a response to your comment on patch #8.

> Reviewed-by: Pierre Morel<[e-mail]>

Thanks!
Halil

Cornelia Huck May 13, 2019, 1:54 p.m. UTC | #4

On Fri, 26 Apr 2019 20:32:44 +0200
Halil Pasic <[e-mail]> wrote:

> Before virtio-ccw could get away with not using DMA API for the pieces of
> memory it does ccw I/O with. With protected virtualization this has to
> change, since the hypervisor needs to read and sometimes also write these
> pieces of memory.
> 
> The hypervisor is supposed to poke the classic notifiers, if these are
> used, out of band with regards to ccw I/O. So these need to be allocated
> as DMA memory (which is shared memory for protected virtualization
> guests).
> 
> Let us factor out everything from struct virtio_ccw_device that needs to
> be DMA memory in a satellite that is allocated as such.
> 
> Note: The control blocks of I/O instructions do not need to be shared.
> These are marshalled by the ultravisor.
> 
> Signed-off-by: Halil Pasic <[e-mail]>
> ---
>  drivers/s390/virtio/virtio_ccw.c | 177 +++++++++++++++++++++------------------
>  1 file changed, 96 insertions(+), 81 deletions(-)
> 

> @@ -176,6 +180,22 @@ static struct virtio_ccw_device *to_vc_device(struct virtio_device *vdev)
>  	return container_of(vdev, struct virtio_ccw_device, vdev);
>  }
>  
> +static inline void *__vc_dma_alloc(struct virtio_device *vdev, size_t size)
> +{
> +	return ccw_device_dma_zalloc(to_vc_device(vdev)->cdev, size);
> +}
> +
> +static inline void __vc_dma_free(struct virtio_device *vdev, size_t size,
> +				 void *cpu_addr)
> +{
> +	return ccw_device_dma_free(to_vc_device(vdev)->cdev, cpu_addr, size);
> +}

Hm, why do these use leading underscores?

Also, maybe make the _free function safe for NULL to simplify the
cleanup paths?


> +
> +#define vc_dma_alloc_struct(vdev, ptr) \
> +	({ptr = __vc_dma_alloc(vdev, sizeof(*(ptr))); })
> +#define vc_dma_free_struct(vdev, ptr) \
> +	__vc_dma_free(vdev, sizeof(*(ptr)), (ptr))

I find these a bit ugly... does adding a wrapper help that much?

> +
>  static void drop_airq_indicator(struct virtqueue *vq, struct airq_info *info)
>  {
>  	unsigned long i, flags;

Patch

diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index 1f3e7d56924f..613b18001a0c 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -46,9 +46,15 @@  struct vq_config_block {
 #define VIRTIO_CCW_CONFIG_SIZE 0x100
 /* same as PCI config space size, should be enough for all drivers */
 
+struct vcdev_dma_area {
+	unsigned long indicators;
+	unsigned long indicators2;
+	struct vq_config_block config_block;
+	__u8 status;
+};
+
 struct virtio_ccw_device {
 	struct virtio_device vdev;
-	__u8 *status;
 	__u8 config[VIRTIO_CCW_CONFIG_SIZE];
 	struct ccw_device *cdev;
 	__u32 curr_io;
@@ -58,24 +64,22 @@  struct virtio_ccw_device {
 	spinlock_t lock;
 	struct mutex io_lock; /* Serializes I/O requests */
 	struct list_head virtqueues;
-	unsigned long indicators;
-	unsigned long indicators2;
-	struct vq_config_block *config_block;
 	bool is_thinint;
 	bool going_away;
 	bool device_lost;
 	unsigned int config_ready;
 	void *airq_info;
+	struct vcdev_dma_area *dma_area;
 };
 
 static inline unsigned long *indicators(struct virtio_ccw_device *vcdev)
 {
-	return &vcdev->indicators;
+	return &vcdev->dma_area->indicators;
 }
 
 static inline unsigned long *indicators2(struct virtio_ccw_device *vcdev)
 {
-	return &vcdev->indicators2;
+	return &vcdev->dma_area->indicators2;
 }
 
 struct vq_info_block_legacy {
@@ -176,6 +180,22 @@  static struct virtio_ccw_device *to_vc_device(struct virtio_device *vdev)
 	return container_of(vdev, struct virtio_ccw_device, vdev);
 }
 
+static inline void *__vc_dma_alloc(struct virtio_device *vdev, size_t size)
+{
+	return ccw_device_dma_zalloc(to_vc_device(vdev)->cdev, size);
+}
+
+static inline void __vc_dma_free(struct virtio_device *vdev, size_t size,
+				 void *cpu_addr)
+{
+	return ccw_device_dma_free(to_vc_device(vdev)->cdev, cpu_addr, size);
+}
+
+#define vc_dma_alloc_struct(vdev, ptr) \
+	({ptr = __vc_dma_alloc(vdev, sizeof(*(ptr))); })
+#define vc_dma_free_struct(vdev, ptr) \
+	__vc_dma_free(vdev, sizeof(*(ptr)), (ptr))
+
 static void drop_airq_indicator(struct virtqueue *vq, struct airq_info *info)
 {
 	unsigned long i, flags;
@@ -335,8 +355,7 @@  static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev,
 	struct airq_info *airq_info = vcdev->airq_info;
 
 	if (vcdev->is_thinint) {
-		thinint_area = kzalloc(sizeof(*thinint_area),
-				       GFP_DMA | GFP_KERNEL);
+		vc_dma_alloc_struct(&vcdev->vdev, thinint_area);
 		if (!thinint_area)
 			return;
 		thinint_area->summary_indicator =
@@ -347,8 +366,8 @@  static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev,
 		ccw->cda = (__u32)(unsigned long) thinint_area;
 	} else {
 		/* payload is the address of the indicators */
-		indicatorp = kmalloc(sizeof(indicators(vcdev)),
-				     GFP_DMA | GFP_KERNEL);
+		indicatorp = __vc_dma_alloc(&vcdev->vdev,
+					   sizeof(indicators(vcdev)));
 		if (!indicatorp)
 			return;
 		*indicatorp = 0;
@@ -368,8 +387,9 @@  static void virtio_ccw_drop_indicator(struct virtio_ccw_device *vcdev,
 			 "Failed to deregister indicators (%d)\n", ret);
 	else if (vcdev->is_thinint)
 		virtio_ccw_drop_indicators(vcdev);
-	kfree(indicatorp);
-	kfree(thinint_area);
+	__vc_dma_free(&vcdev->vdev, sizeof(indicators(vcdev)),
+		      indicatorp);
+	vc_dma_free_struct(&vcdev->vdev, thinint_area);
 }
 
 static inline long __do_kvm_notify(struct subchannel_id schid,
@@ -416,15 +436,15 @@  static int virtio_ccw_read_vq_conf(struct virtio_ccw_device *vcdev,
 {
 	int ret;
 
-	vcdev->config_block->index = index;
+	vcdev->dma_area->config_block.index = index;
 	ccw->cmd_code = CCW_CMD_READ_VQ_CONF;
 	ccw->flags = 0;
 	ccw->count = sizeof(struct vq_config_block);
-	ccw->cda = (__u32)(unsigned long)(vcdev->config_block);
+	ccw->cda = (__u32)(unsigned long)(&vcdev->dma_area->config_block);
 	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_READ_VQ_CONF);
 	if (ret)
 		return ret;
-	return vcdev->config_block->num ?: -ENOENT;
+	return vcdev->dma_area->config_block.num ?: -ENOENT;
 }
 
 static void virtio_ccw_del_vq(struct virtqueue *vq, struct ccw1 *ccw)
@@ -469,7 +489,7 @@  static void virtio_ccw_del_vq(struct virtqueue *vq, struct ccw1 *ccw)
 			 ret, index);
 
 	vring_del_virtqueue(vq);
-	kfree(info->info_block);
+	vc_dma_free_struct(vq->vdev, info->info_block);
 	kfree(info);
 }
 
@@ -479,7 +499,7 @@  static void virtio_ccw_del_vqs(struct virtio_device *vdev)
 	struct ccw1 *ccw;
 	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
 
-	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	vc_dma_alloc_struct(vdev, ccw);
 	if (!ccw)
 		return;
 
@@ -488,7 +508,7 @@  static void virtio_ccw_del_vqs(struct virtio_device *vdev)
 	list_for_each_entry_safe(vq, n, &vdev->vqs, list)
 		virtio_ccw_del_vq(vq, ccw);
 
-	kfree(ccw);
+	vc_dma_free_struct(vdev, ccw);
 }
 
 static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
@@ -511,8 +531,7 @@  static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
 		err = -ENOMEM;
 		goto out_err;
 	}
-	info->info_block = kzalloc(sizeof(*info->info_block),
-				   GFP_DMA | GFP_KERNEL);
+	vc_dma_alloc_struct(vdev, info->info_block);
 	if (!info->info_block) {
 		dev_warn(&vcdev->cdev->dev, "no info block\n");
 		err = -ENOMEM;
@@ -576,7 +595,7 @@  static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
 	if (vq)
 		vring_del_virtqueue(vq);
 	if (info) {
-		kfree(info->info_block);
+		vc_dma_free_struct(vdev, info->info_block);
 	}
 	kfree(info);
 	return ERR_PTR(err);
@@ -590,7 +609,7 @@  static int virtio_ccw_register_adapter_ind(struct virtio_ccw_device *vcdev,
 	struct virtio_thinint_area *thinint_area = NULL;
 	struct airq_info *info;
 
-	thinint_area = kzalloc(sizeof(*thinint_area), GFP_DMA | GFP_KERNEL);
+	vc_dma_alloc_struct(&vcdev->vdev, thinint_area);
 	if (!thinint_area) {
 		ret = -ENOMEM;
 		goto out;
@@ -626,7 +645,7 @@  static int virtio_ccw_register_adapter_ind(struct virtio_ccw_device *vcdev,
 		virtio_ccw_drop_indicators(vcdev);
 	}
 out:
-	kfree(thinint_area);
+	vc_dma_free_struct(&vcdev->vdev, thinint_area);
 	return ret;
 }
 
@@ -642,7 +661,7 @@  static int virtio_ccw_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 	int ret, i, queue_idx = 0;
 	struct ccw1 *ccw;
 
-	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	vc_dma_alloc_struct(vdev, ccw);
 	if (!ccw)
 		return -ENOMEM;
 
@@ -666,7 +685,7 @@  static int virtio_ccw_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 	 * We need a data area under 2G to communicate. Our payload is
 	 * the address of the indicators.
 	*/
-	indicatorp = kmalloc(sizeof(indicators(vcdev)), GFP_DMA | GFP_KERNEL);
+	indicatorp = __vc_dma_alloc(&vcdev->vdev, sizeof(indicators(vcdev)));
 	if (!indicatorp)
 		goto out;
 	*indicatorp = (unsigned long) indicators(vcdev);
@@ -698,12 +717,16 @@  static int virtio_ccw_find_vqs(struct virtio_device *vdev, unsigned nvqs,
 	if (ret)
 		goto out;
 
-	kfree(indicatorp);
-	kfree(ccw);
+	if (indicatorp)
+		__vc_dma_free(&vcdev->vdev, sizeof(indicators(vcdev)),
+			       indicatorp);
+	vc_dma_free_struct(vdev, ccw);
 	return 0;
 out:
-	kfree(indicatorp);
-	kfree(ccw);
+	if (indicatorp)
+		__vc_dma_free(&vcdev->vdev, sizeof(indicators(vcdev)),
+			       indicatorp);
+	vc_dma_free_struct(vdev, ccw);
 	virtio_ccw_del_vqs(vdev);
 	return ret;
 }
@@ -713,12 +736,12 @@  static void virtio_ccw_reset(struct virtio_device *vdev)
 	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
 	struct ccw1 *ccw;
 
-	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	vc_dma_alloc_struct(vdev, ccw);
 	if (!ccw)
 		return;
 
 	/* Zero status bits. */
-	*vcdev->status = 0;
+	vcdev->dma_area->status = 0;
 
 	/* Send a reset ccw on device. */
 	ccw->cmd_code = CCW_CMD_VDEV_RESET;
@@ -726,22 +749,22 @@  static void virtio_ccw_reset(struct virtio_device *vdev)
 	ccw->count = 0;
 	ccw->cda = 0;
 	ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_RESET);
-	kfree(ccw);
+	vc_dma_free_struct(vdev, ccw);
 }
 
 static u64 virtio_ccw_get_features(struct virtio_device *vdev)
 {
 	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
 	struct virtio_feature_desc *features;
+	struct ccw1 *ccw;
 	int ret;
 	u64 rc;
-	struct ccw1 *ccw;
 
-	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	vc_dma_alloc_struct(vdev, ccw);
 	if (!ccw)
 		return 0;
 
-	features = kzalloc(sizeof(*features), GFP_DMA | GFP_KERNEL);
+	vc_dma_alloc_struct(vdev, features);
 	if (!features) {
 		rc = 0;
 		goto out_free;
@@ -774,8 +797,8 @@  static u64 virtio_ccw_get_features(struct virtio_device *vdev)
 		rc |= (u64)le32_to_cpu(features->features) << 32;
 
 out_free:
-	kfree(features);
-	kfree(ccw);
+	vc_dma_free_struct(vdev, features);
+	vc_dma_free_struct(vdev, ccw);
 	return rc;
 }
 
@@ -800,11 +823,11 @@  static int virtio_ccw_finalize_features(struct virtio_device *vdev)
 		return -EINVAL;
 	}
 
-	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	vc_dma_alloc_struct(vdev, ccw);
 	if (!ccw)
 		return -ENOMEM;
 
-	features = kzalloc(sizeof(*features), GFP_DMA | GFP_KERNEL);
+	vc_dma_alloc_struct(vdev, features);
 	if (!features) {
 		ret = -ENOMEM;
 		goto out_free;
@@ -839,8 +862,8 @@  static int virtio_ccw_finalize_features(struct virtio_device *vdev)
 	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);
 
 out_free:
-	kfree(features);
-	kfree(ccw);
+	vc_dma_free_struct(vdev, features);
+	vc_dma_free_struct(vdev, ccw);
 
 	return ret;
 }
@@ -854,11 +877,11 @@  static void virtio_ccw_get_config(struct virtio_device *vdev,
 	void *config_area;
 	unsigned long flags;
 
-	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	vc_dma_alloc_struct(vdev, ccw);
 	if (!ccw)
 		return;
 
-	config_area = kzalloc(VIRTIO_CCW_CONFIG_SIZE, GFP_DMA | GFP_KERNEL);
+	config_area = __vc_dma_alloc(vdev, VIRTIO_CCW_CONFIG_SIZE);
 	if (!config_area)
 		goto out_free;
 
@@ -880,8 +903,8 @@  static void virtio_ccw_get_config(struct virtio_device *vdev,
 		memcpy(buf, config_area + offset, len);
 
 out_free:
-	kfree(config_area);
-	kfree(ccw);
+	__vc_dma_free(vdev, VIRTIO_CCW_CONFIG_SIZE, config_area);
+	vc_dma_free_struct(vdev, ccw);
 }
 
 static void virtio_ccw_set_config(struct virtio_device *vdev,
@@ -893,11 +916,11 @@  static void virtio_ccw_set_config(struct virtio_device *vdev,
 	void *config_area;
 	unsigned long flags;
 
-	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	vc_dma_alloc_struct(vdev, ccw);
 	if (!ccw)
 		return;
 
-	config_area = kzalloc(VIRTIO_CCW_CONFIG_SIZE, GFP_DMA | GFP_KERNEL);
+	config_area = __vc_dma_alloc(vdev, VIRTIO_CCW_CONFIG_SIZE);
 	if (!config_area)
 		goto out_free;
 
@@ -916,61 +939,61 @@  static void virtio_ccw_set_config(struct virtio_device *vdev,
 	ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_CONFIG);
 
 out_free:
-	kfree(config_area);
-	kfree(ccw);
+	__vc_dma_free(vdev, VIRTIO_CCW_CONFIG_SIZE, config_area);
+	vc_dma_free_struct(vdev, ccw);
 }
 
 static u8 virtio_ccw_get_status(struct virtio_device *vdev)
 {
 	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
-	u8 old_status = *vcdev->status;
+	u8 old_status = vcdev->dma_area->status;
 	struct ccw1 *ccw;
 
 	if (vcdev->revision < 1)
-		return *vcdev->status;
+		return vcdev->dma_area->status;
 
-	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	vc_dma_alloc_struct(vdev, ccw);
 	if (!ccw)
 		return old_status;
 
 	ccw->cmd_code = CCW_CMD_READ_STATUS;
 	ccw->flags = 0;
-	ccw->count = sizeof(*vcdev->status);
-	ccw->cda = (__u32)(unsigned long)vcdev->status;
+	ccw->count = sizeof(vcdev->dma_area->status);
+	ccw->cda = (__u32)(unsigned long)&vcdev->dma_area->status;
 	ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_READ_STATUS);
 /*
  * If the channel program failed (should only happen if the device
  * was hotunplugged, and then we clean up via the machine check
- * handler anyway), vcdev->status was not overwritten and we just
+ * handler anyway), vcdev->dma_area->status was not overwritten and we just
  * return the old status, which is fine.
 */
-	kfree(ccw);
+	vc_dma_free_struct(vdev, ccw);
 
-	return *vcdev->status;
+	return vcdev->dma_area->status;
 }
 
 static void virtio_ccw_set_status(struct virtio_device *vdev, u8 status)
 {
 	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
-	u8 old_status = *vcdev->status;
+	u8 old_status = vcdev->dma_area->status;
 	struct ccw1 *ccw;
 	int ret;
 
-	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	vc_dma_alloc_struct(vdev, ccw);
 	if (!ccw)
 		return;
 
 	/* Write the status to the host. */
-	*vcdev->status = status;
+	vcdev->dma_area->status = status;
 	ccw->cmd_code = CCW_CMD_WRITE_STATUS;
 	ccw->flags = 0;
 	ccw->count = sizeof(status);
-	ccw->cda = (__u32)(unsigned long)vcdev->status;
+	ccw->cda = (__u32)(unsigned long)&vcdev->dma_area->status;
 	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_STATUS);
 	/* Write failed? We assume status is unchanged. */
 	if (ret)
-		*vcdev->status = old_status;
-	kfree(ccw);
+		vcdev->dma_area->status = old_status;
+	vc_dma_free_struct(vdev, ccw);
 }
 
 static const char *virtio_ccw_bus_name(struct virtio_device *vdev)
@@ -1003,8 +1026,7 @@  static void virtio_ccw_release_dev(struct device *_d)
 	struct virtio_device *dev = dev_to_virtio(_d);
 	struct virtio_ccw_device *vcdev = to_vc_device(dev);
 
-	kfree(vcdev->status);
-	kfree(vcdev->config_block);
+	vc_dma_free_struct(&vcdev->vdev, vcdev->dma_area);
 	kfree(vcdev);
 }
 
@@ -1212,12 +1234,12 @@  static int virtio_ccw_set_transport_rev(struct virtio_ccw_device *vcdev)
 	struct ccw1 *ccw;
 	int ret;
 
-	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	vc_dma_alloc_struct(&vcdev->vdev, ccw);
 	if (!ccw)
 		return -ENOMEM;
-	rev = kzalloc(sizeof(*rev), GFP_DMA | GFP_KERNEL);
+	vc_dma_alloc_struct(&vcdev->vdev, rev);
 	if (!rev) {
-		kfree(ccw);
+		vc_dma_free_struct(&vcdev->vdev, ccw);
 		return -ENOMEM;
 	}
 
@@ -1247,8 +1269,8 @@  static int virtio_ccw_set_transport_rev(struct virtio_ccw_device *vcdev)
 		}
 	} while (ret == -EOPNOTSUPP);
 
-	kfree(ccw);
-	kfree(rev);
+	vc_dma_free_struct(&vcdev->vdev, ccw);
+	vc_dma_free_struct(&vcdev->vdev, rev);
 	return ret;
 }
 
@@ -1265,14 +1287,9 @@  static int virtio_ccw_online(struct ccw_device *cdev)
 		goto out_free;
 	}
 	vcdev->vdev.dev.parent = &cdev->dev;
-	vcdev->config_block = kzalloc(sizeof(*vcdev->config_block),
-				   GFP_DMA | GFP_KERNEL);
-	if (!vcdev->config_block) {
-		ret = -ENOMEM;
-		goto out_free;
-	}
-	vcdev->status = kzalloc(sizeof(*vcdev->status), GFP_DMA | GFP_KERNEL);
-	if (!vcdev->status) {
+	vcdev->cdev = cdev;
+	vc_dma_alloc_struct(&vcdev->vdev, vcdev->dma_area);
+	if (!vcdev->dma_area) {
 		ret = -ENOMEM;
 		goto out_free;
 	}
@@ -1281,7 +1298,6 @@  static int virtio_ccw_online(struct ccw_device *cdev)
 
 	vcdev->vdev.dev.release = virtio_ccw_release_dev;
 	vcdev->vdev.config = &virtio_ccw_config_ops;
-	vcdev->cdev = cdev;
 	init_waitqueue_head(&vcdev->wait_q);
 	INIT_LIST_HEAD(&vcdev->virtqueues);
 	spin_lock_init(&vcdev->lock);
@@ -1312,8 +1328,7 @@  static int virtio_ccw_online(struct ccw_device *cdev)
 	return ret;
 out_free:
 	if (vcdev) {
-		kfree(vcdev->status);
-		kfree(vcdev->config_block);
+		vc_dma_free_struct(&vcdev->vdev, vcdev->dma_area);
 	}
 	kfree(vcdev);
 	return ret;