[PATCH RFC v2 01/16] virtio: memory access APIs

[PATCH RFC v2 01/16] virtio: memory access APIs

[Michael S. Tsirkin]

virtio 1.0 makes all memory structures LE, so
we need APIs to conditionally do a byteswap on BE
architectures.

To make it easier to check code statically,
add virtio specific types for multi-byte integers
in memory.

Add low level wrappers that do a byteswap conditionally, these will be
useful e.g. for vhost.  Add high level wrappers that will (in the
future) query device endian-ness and act accordingly.

At the moment, stub them out and assume native endian-ness everywhere.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/linux/virtio_config.h    | 16 +++++++++++++
 include/uapi/linux/virtio_ring.h | 49 ++++++++++++++++++++--------------------
 include/uapi/linux/Kbuild        |  1 +
 3 files changed, 42 insertions(+), 24 deletions(-)

diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index 7f4ef66..d38d3c2 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -4,6 +4,7 @@
 #include <linux/err.h>
 #include <linux/bug.h>
 #include <linux/virtio.h>
+#include <linux/virtio_byteorder.h>
 #include <uapi/linux/virtio_config.h>
 
 /**
@@ -152,6 +153,21 @@ int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
 	return 0;
 }
 
+/* Memory accessors */
+#define DEFINE_VIRTIO_XX_TO_CPU(bits) \
+static inline u##bits virtio##bits##_to_cpu(struct virtio_device *vdev, __virtio##bits val) \
+{ \
+	return __virtio##bits##_to_cpu(false, val); \
+} \
+static inline __virtio##bits cpu_to_virtio##bits(struct virtio_device *vdev, u##bits val) \
+{ \
+	return __cpu_to_virtio##bits(false, val); \
+}
+
+DEFINE_VIRTIO_XX_TO_CPU(16)
+DEFINE_VIRTIO_XX_TO_CPU(32)
+DEFINE_VIRTIO_XX_TO_CPU(64)
+
 /* Config space accessors. */
 #define virtio_cread(vdev, structname, member, ptr)			\
 	do {								\
diff --git a/include/uapi/linux/virtio_ring.h b/include/uapi/linux/virtio_ring.h
index a99f9b7..6c00632 100644
--- a/include/uapi/linux/virtio_ring.h
+++ b/include/uapi/linux/virtio_ring.h
@@ -32,6 +32,7 @@
  *
  * Copyright Rusty Russell IBM Corporation 2007. */
 #include <linux/types.h>
+#include <linux/virtio_types.h>
 
 /* This marks a buffer as continuing via the next field. */
 #define VRING_DESC_F_NEXT	1
@@ -61,32 +62,32 @@
 /* Virtio ring descriptors: 16 bytes.  These can chain together via "next". */
 struct vring_desc {
 	/* Address (guest-physical). */
-	__u64 addr;
+	__virtio64 addr;
 	/* Length. */
-	__u32 len;
+	__virtio32 len;
 	/* The flags as indicated above. */
-	__u16 flags;
+	__virtio16 flags;
 	/* We chain unused descriptors via this, too */
-	__u16 next;
+	__virtio16 next;
 };
 
 struct vring_avail {
-	__u16 flags;
-	__u16 idx;
-	__u16 ring[];
+	__virtio16 flags;
+	__virtio16 idx;
+	__virtio16 ring[];
 };
 
 /* u32 is used here for ids for padding reasons. */
 struct vring_used_elem {
 	/* Index of start of used descriptor chain. */
-	__u32 id;
+	__virtio32 id;
 	/* Total length of the descriptor chain which was used (written to) */
-	__u32 len;
+	__virtio32 len;
 };
 
 struct vring_used {
-	__u16 flags;
-	__u16 idx;
+	__virtio16 flags;
+	__virtio16 idx;
 	struct vring_used_elem ring[];
 };
 
@@ -109,25 +110,25 @@ struct vring {
  *	struct vring_desc desc[num];
  *
  *	// A ring of available descriptor heads with free-running index.
- *	__u16 avail_flags;
- *	__u16 avail_idx;
- *	__u16 available[num];
- *	__u16 used_event_idx;
+ *	__virtio16 avail_flags;
+ *	__virtio16 avail_idx;
+ *	__virtio16 available[num];
+ *	__virtio16 used_event_idx;
  *
  *	// Padding to the next align boundary.
  *	char pad[];
  *
  *	// A ring of used descriptor heads with free-running index.
- *	__u16 used_flags;
- *	__u16 used_idx;
+ *	__virtio16 used_flags;
+ *	__virtio16 used_idx;
  *	struct vring_used_elem used[num];
- *	__u16 avail_event_idx;
+ *	__virtio16 avail_event_idx;
  * };
  */
 /* We publish the used event index at the end of the available ring, and vice
  * versa. They are at the end for backwards compatibility. */
 #define vring_used_event(vr) ((vr)->avail->ring[(vr)->num])
-#define vring_avail_event(vr) (*(__u16 *)&(vr)->used->ring[(vr)->num])
+#define vring_avail_event(vr) (*(__virtio16 *)&(vr)->used->ring[(vr)->num])
 
 static inline void vring_init(struct vring *vr, unsigned int num, void *p,
 			      unsigned long align)
@@ -135,29 +136,29 @@ static inline void vring_init(struct vring *vr, unsigned int num, void *p,
 	vr->num = num;
 	vr->desc = p;
 	vr->avail = p + num*sizeof(struct vring_desc);
-	vr->used = (void *)(((unsigned long)&vr->avail->ring[num] + sizeof(__u16)
+	vr->used = (void *)(((unsigned long)&vr->avail->ring[num] + sizeof(__virtio16)
 		+ align-1) & ~(align - 1));
 }
 
 static inline unsigned vring_size(unsigned int num, unsigned long align)
 {
-	return ((sizeof(struct vring_desc) * num + sizeof(__u16) * (3 + num)
+	return ((sizeof(struct vring_desc) * num + sizeof(__virtio16) * (3 + num)
 		 + align - 1) & ~(align - 1))
-		+ sizeof(__u16) * 3 + sizeof(struct vring_used_elem) * num;
+		+ sizeof(__virtio16) * 3 + sizeof(struct vring_used_elem) * num;
 }
 
 /* The following is used with USED_EVENT_IDX and AVAIL_EVENT_IDX */
 /* Assuming a given event_idx value from the other size, if
  * we have just incremented index from old to new_idx,
  * should we trigger an event? */
-static inline int vring_need_event(__u16 event_idx, __u16 new_idx, __u16 old)
+static inline int vring_need_event(__virtio16 event_idx, __virtio16 new_idx, __virtio16 old)
 {
 	/* Note: Xen has similar logic for notification hold-off
 	 * in include/xen/interface/io/ring.h with req_event and req_prod
 	 * corresponding to event_idx + 1 and new_idx respectively.
 	 * Note also that req_event and req_prod in Xen start at 1,
 	 * event indexes in virtio start at 0. */
-	return (__u16)(new_idx - event_idx - 1) < (__u16)(new_idx - old);
+	return (__virtio16)(new_idx - event_idx - 1) < (__virtio16)(new_idx - old);
 }
 
 #endif /* _UAPI_LINUX_VIRTIO_RING_H */
diff --git a/include/uapi/linux/Kbuild b/include/uapi/linux/Kbuild
index 6cad974..39c161a 100644
--- a/include/uapi/linux/Kbuild
+++ b/include/uapi/linux/Kbuild
@@ -419,6 +419,7 @@ header-y += virtio_blk.h
 header-y += virtio_config.h
 header-y += virtio_console.h
 header-y += virtio_ids.h
+header-y += virtio_types.h
 header-y += virtio_net.h
 header-y += virtio_pci.h
 header-y += virtio_ring.h
-- 
MST

Re: [PATCH RFC v2 01/16] virtio: memory access APIs

[Christopher Covington]

Hi Michael,

On 10/22/2014 11:50 AM, Michael S. Tsirkin wrote:
> virtio 1.0 makes all memory structures LE, so
> we need APIs to conditionally do a byteswap on BE
> architectures.
> 
> To make it easier to check code statically,
> add virtio specific types for multi-byte integers
> in memory.
> 
> Add low level wrappers that do a byteswap conditionally, these will be
> useful e.g. for vhost.  Add high level wrappers that will (in the
> future) query device endian-ness and act accordingly.
> 
> At the moment, stub them out and assume native endian-ness everywhere.
> 
> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  include/linux/virtio_config.h    | 16 +++++++++++++
>  include/uapi/linux/virtio_ring.h | 49 ++++++++++++++++++++--------------------
>  include/uapi/linux/Kbuild        |  1 +
>  3 files changed, 42 insertions(+), 24 deletions(-)
> 
> diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
> index 7f4ef66..d38d3c2 100644
> --- a/include/linux/virtio_config.h
> +++ b/include/linux/virtio_config.h
> @@ -4,6 +4,7 @@
>  #include <linux/err.h>
>  #include <linux/bug.h>
>  #include <linux/virtio.h>
> +#include <linux/virtio_byteorder.h>

What patch creates this file?

>  #include <uapi/linux/virtio_config.h>
>  
>  /**
> @@ -152,6 +153,21 @@ int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
>  	return 0;
>  }
>  
> +/* Memory accessors */
> +#define DEFINE_VIRTIO_XX_TO_CPU(bits) \
> +static inline u##bits virtio##bits##_to_cpu(struct virtio_device *vdev, __virtio##bits val) \
> +{ \
> +	return __virtio##bits##_to_cpu(false, val); \
> +} \
> +static inline __virtio##bits cpu_to_virtio##bits(struct virtio_device *vdev, u##bits val) \
> +{ \
> +	return __cpu_to_virtio##bits(false, val); \
> +}
> +
> +DEFINE_VIRTIO_XX_TO_CPU(16)
> +DEFINE_VIRTIO_XX_TO_CPU(32)
> +DEFINE_VIRTIO_XX_TO_CPU(64)
> +
>  /* Config space accessors. */
>  #define virtio_cread(vdev, structname, member, ptr)			\
>  	do {								\
> diff --git a/include/uapi/linux/virtio_ring.h b/include/uapi/linux/virtio_ring.h
> index a99f9b7..6c00632 100644
> --- a/include/uapi/linux/virtio_ring.h
> +++ b/include/uapi/linux/virtio_ring.h
> @@ -32,6 +32,7 @@
>   *
>   * Copyright Rusty Russell IBM Corporation 2007. */
>  #include <linux/types.h>
> +#include <linux/virtio_types.h>
>  
>  /* This marks a buffer as continuing via the next field. */
>  #define VRING_DESC_F_NEXT	1
> @@ -61,32 +62,32 @@
>  /* Virtio ring descriptors: 16 bytes.  These can chain together via "next". */
>  struct vring_desc {
>  	/* Address (guest-physical). */
> -	__u64 addr;
> +	__virtio64 addr;
>  	/* Length. */
> -	__u32 len;
> +	__virtio32 len;
>  	/* The flags as indicated above. */
> -	__u16 flags;
> +	__virtio16 flags;
>  	/* We chain unused descriptors via this, too */
> -	__u16 next;
> +	__virtio16 next;
>  };

How does __virtio64 differ from __le64?

Thanks,
Chris

-- 
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH RFC v2 01/16] virtio: memory access APIs

[Michael S. Tsirkin]

On Wed, Oct 22, 2014 at 01:45:55PM -0400, Christopher Covington wrote:
> Hi Michael,
> 
> On 10/22/2014 11:50 AM, Michael S. Tsirkin wrote:
> > virtio 1.0 makes all memory structures LE, so
> > we need APIs to conditionally do a byteswap on BE
> > architectures.
> > 
> > To make it easier to check code statically,
> > add virtio specific types for multi-byte integers
> > in memory.
> > 
> > Add low level wrappers that do a byteswap conditionally, these will be
> > useful e.g. for vhost.  Add high level wrappers that will (in the
> > future) query device endian-ness and act accordingly.
> > 
> > At the moment, stub them out and assume native endian-ness everywhere.
> > 
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> >  include/linux/virtio_config.h    | 16 +++++++++++++
> >  include/uapi/linux/virtio_ring.h | 49 ++++++++++++++++++++--------------------
> >  include/uapi/linux/Kbuild        |  1 +
> >  3 files changed, 42 insertions(+), 24 deletions(-)
> > 
> > diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
> > index 7f4ef66..d38d3c2 100644
> > --- a/include/linux/virtio_config.h
> > +++ b/include/linux/virtio_config.h
> > @@ -4,6 +4,7 @@
> >  #include <linux/err.h>
> >  #include <linux/bug.h>
> >  #include <linux/virtio.h>
> > +#include <linux/virtio_byteorder.h>
> 
> What patch creates this file?

Oops I forgot to git add it.
Will resend.

> >  #include <uapi/linux/virtio_config.h>
> >  
> >  /**
> > @@ -152,6 +153,21 @@ int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
> >  	return 0;
> >  }
> >  
> > +/* Memory accessors */
> > +#define DEFINE_VIRTIO_XX_TO_CPU(bits) \
> > +static inline u##bits virtio##bits##_to_cpu(struct virtio_device *vdev, __virtio##bits val) \
> > +{ \
> > +	return __virtio##bits##_to_cpu(false, val); \
> > +} \
> > +static inline __virtio##bits cpu_to_virtio##bits(struct virtio_device *vdev, u##bits val) \
> > +{ \
> > +	return __cpu_to_virtio##bits(false, val); \
> > +}
> > +
> > +DEFINE_VIRTIO_XX_TO_CPU(16)
> > +DEFINE_VIRTIO_XX_TO_CPU(32)
> > +DEFINE_VIRTIO_XX_TO_CPU(64)
> > +
> >  /* Config space accessors. */
> >  #define virtio_cread(vdev, structname, member, ptr)			\
> >  	do {								\
> > diff --git a/include/uapi/linux/virtio_ring.h b/include/uapi/linux/virtio_ring.h
> > index a99f9b7..6c00632 100644
> > --- a/include/uapi/linux/virtio_ring.h
> > +++ b/include/uapi/linux/virtio_ring.h
> > @@ -32,6 +32,7 @@
> >   *
> >   * Copyright Rusty Russell IBM Corporation 2007. */
> >  #include <linux/types.h>
> > +#include <linux/virtio_types.h>
> >  
> >  /* This marks a buffer as continuing via the next field. */
> >  #define VRING_DESC_F_NEXT	1
> > @@ -61,32 +62,32 @@
> >  /* Virtio ring descriptors: 16 bytes.  These can chain together via "next". */
> >  struct vring_desc {
> >  	/* Address (guest-physical). */
> > -	__u64 addr;
> > +	__virtio64 addr;
> >  	/* Length. */
> > -	__u32 len;
> > +	__virtio32 len;
> >  	/* The flags as indicated above. */
> > -	__u16 flags;
> > +	__virtio16 flags;
> >  	/* We chain unused descriptors via this, too */
> > -	__u16 next;
> > +	__virtio16 next;
> >  };
> 
> How does __virtio64 differ from __le64?
> 
> Thanks,
> Chris

__le64 would require cpu_to_le, I wanted to force the use
of our byte swapping macros.

> -- 
> Qualcomm Innovation Center, Inc.
> The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
> a Linux Foundation Collaborative Project

[PATCH RFC v2 02/16] virtio_ring: switch to new memory access APIs

[Michael S. Tsirkin]

Use virtioXX_to_cpu and friends for access to
all multibyte structures in memory.

Note: this is intentionally mechanical.
A follow-up patch will split long lines etc.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/virtio/virtio_ring.c | 89 ++++++++++++++++++++++----------------------
 1 file changed, 45 insertions(+), 44 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 3b1f89b..048e1bc 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -99,7 +99,8 @@ struct vring_virtqueue
 
 #define to_vvq(_vq) container_of(_vq, struct vring_virtqueue, vq)
 
-static struct vring_desc *alloc_indirect(unsigned int total_sg, gfp_t gfp)
+static struct vring_desc *alloc_indirect(struct virtqueue *_vq,
+					 unsigned int total_sg, gfp_t gfp)
 {
 	struct vring_desc *desc;
 	unsigned int i;
@@ -116,7 +117,7 @@ static struct vring_desc *alloc_indirect(unsigned int total_sg, gfp_t gfp)
 		return NULL;
 
 	for (i = 0; i < total_sg; i++)
-		desc[i].next = i+1;
+		desc[i].next = cpu_to_virtio16(_vq->vdev, i + 1);
 	return desc;
 }
 
@@ -165,17 +166,17 @@ static inline int virtqueue_add(struct virtqueue *_vq,
 	/* If the host supports indirect descriptor tables, and we have multiple
 	 * buffers, then go indirect. FIXME: tune this threshold */
 	if (vq->indirect && total_sg > 1 && vq->vq.num_free)
-		desc = alloc_indirect(total_sg, gfp);
+		desc = alloc_indirect(_vq, total_sg, gfp);
 	else
 		desc = NULL;
 
 	if (desc) {
 		/* Use a single buffer which doesn't continue */
-		vq->vring.desc[head].flags = VRING_DESC_F_INDIRECT;
-		vq->vring.desc[head].addr = virt_to_phys(desc);
+		vq->vring.desc[head].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_INDIRECT);
+		vq->vring.desc[head].addr = cpu_to_virtio64(_vq->vdev, virt_to_phys(desc));
 		/* avoid kmemleak false positive (hidden by virt_to_phys) */
 		kmemleak_ignore(desc);
-		vq->vring.desc[head].len = total_sg * sizeof(struct vring_desc);
+		vq->vring.desc[head].len = cpu_to_virtio32(_vq->vdev, total_sg * sizeof(struct vring_desc));
 
 		/* Set up rest to use this indirect table. */
 		i = 0;
@@ -205,28 +206,28 @@ static inline int virtqueue_add(struct virtqueue *_vq,
 
 	for (n = 0; n < out_sgs; n++) {
 		for (sg = sgs[n]; sg; sg = sg_next(sg)) {
-			desc[i].flags = VRING_DESC_F_NEXT;
-			desc[i].addr = sg_phys(sg);
-			desc[i].len = sg->length;
+			desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT);
+			desc[i].addr = cpu_to_virtio64(_vq->vdev, sg_phys(sg));
+			desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length);
 			prev = i;
-			i = desc[i].next;
+			i = virtio16_to_cpu(_vq->vdev, desc[i].next);
 		}
 	}
 	for (; n < (out_sgs + in_sgs); n++) {
 		for (sg = sgs[n]; sg; sg = sg_next(sg)) {
-			desc[i].flags = VRING_DESC_F_NEXT|VRING_DESC_F_WRITE;
-			desc[i].addr = sg_phys(sg);
-			desc[i].len = sg->length;
+			desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT | VRING_DESC_F_WRITE);
+			desc[i].addr = cpu_to_virtio64(_vq->vdev, sg_phys(sg));
+			desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length);
 			prev = i;
-			i = desc[i].next;
+			i = virtio16_to_cpu(_vq->vdev, desc[i].next);
 		}
 	}
 	/* Last one doesn't continue. */
-	desc[prev].flags &= ~VRING_DESC_F_NEXT;
+	desc[prev].flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT);
 
 	/* Update free pointer */
 	if (indirect)
-		vq->free_head = vq->vring.desc[head].next;
+		vq->free_head = virtio16_to_cpu(_vq->vdev, vq->vring.desc[head].next);
 	else
 		vq->free_head = i;
 
@@ -235,13 +236,13 @@ static inline int virtqueue_add(struct virtqueue *_vq,
 
 	/* Put entry in available array (but don't update avail->idx until they
 	 * do sync). */
-	avail = (vq->vring.avail->idx & (vq->vring.num-1));
-	vq->vring.avail->ring[avail] = head;
+	avail = virtio16_to_cpu(_vq->vdev, vq->vring.avail->idx) & (vq->vring.num - 1);
+	vq->vring.avail->ring[avail] = cpu_to_virtio16(_vq->vdev, head);
 
 	/* Descriptors and available array need to be set before we expose the
 	 * new available array entries. */
 	virtio_wmb(vq->weak_barriers);
-	vq->vring.avail->idx++;
+	vq->vring.avail->idx = cpu_to_virtio16(_vq->vdev, virtio16_to_cpu(_vq->vdev, vq->vring.avail->idx) + 1);
 	vq->num_added++;
 
 	/* This is very unlikely, but theoretically possible.  Kick
@@ -354,8 +355,8 @@ bool virtqueue_kick_prepare(struct virtqueue *_vq)
 	 * event. */
 	virtio_mb(vq->weak_barriers);
 
-	old = vq->vring.avail->idx - vq->num_added;
-	new = vq->vring.avail->idx;
+	old = virtio16_to_cpu(_vq->vdev, vq->vring.avail->idx) - vq->num_added;
+	new = virtio16_to_cpu(_vq->vdev, vq->vring.avail->idx);
 	vq->num_added = 0;
 
 #ifdef DEBUG
@@ -367,10 +368,10 @@ bool virtqueue_kick_prepare(struct virtqueue *_vq)
 #endif
 
 	if (vq->event) {
-		needs_kick = vring_need_event(vring_avail_event(&vq->vring),
+		needs_kick = vring_need_event(virtio16_to_cpu(_vq->vdev, vring_avail_event(&vq->vring)),
 					      new, old);
 	} else {
-		needs_kick = !(vq->vring.used->flags & VRING_USED_F_NO_NOTIFY);
+		needs_kick = !(vq->vring.used->flags & cpu_to_virtio16(_vq->vdev, VRING_USED_F_NO_NOTIFY));
 	}
 	END_USE(vq);
 	return needs_kick;
@@ -432,15 +433,15 @@ static void detach_buf(struct vring_virtqueue *vq, unsigned int head)
 	i = head;
 
 	/* Free the indirect table */
-	if (vq->vring.desc[i].flags & VRING_DESC_F_INDIRECT)
-		kfree(phys_to_virt(vq->vring.desc[i].addr));
+	if (vq->vring.desc[i].flags & cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_INDIRECT))
+		kfree(phys_to_virt(virtio64_to_cpu(vq->vq.vdev, vq->vring.desc[i].addr)));
 
-	while (vq->vring.desc[i].flags & VRING_DESC_F_NEXT) {
-		i = vq->vring.desc[i].next;
+	while (vq->vring.desc[i].flags & cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT)) {
+		i = virtio16_to_cpu(vq->vq.vdev, vq->vring.desc[i].next);
 		vq->vq.num_free++;
 	}
 
-	vq->vring.desc[i].next = vq->free_head;
+	vq->vring.desc[i].next = cpu_to_virtio16(vq->vq.vdev, vq->free_head);
 	vq->free_head = head;
 	/* Plus final descriptor */
 	vq->vq.num_free++;
@@ -448,7 +449,7 @@ static void detach_buf(struct vring_virtqueue *vq, unsigned int head)
 
 static inline bool more_used(const struct vring_virtqueue *vq)
 {
-	return vq->last_used_idx != vq->vring.used->idx;
+	return vq->last_used_idx != virtio16_to_cpu(vq->vq.vdev, vq->vring.used->idx);
 }
 
 /**
@@ -491,8 +492,8 @@ void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len)
 	virtio_rmb(vq->weak_barriers);
 
 	last_used = (vq->last_used_idx & (vq->vring.num - 1));
-	i = vq->vring.used->ring[last_used].id;
-	*len = vq->vring.used->ring[last_used].len;
+	i = virtio32_to_cpu(_vq->vdev, vq->vring.used->ring[last_used].id);
+	*len = virtio32_to_cpu(_vq->vdev, vq->vring.used->ring[last_used].len);
 
 	if (unlikely(i >= vq->vring.num)) {
 		BAD_RING(vq, "id %u out of range\n", i);
@@ -510,8 +511,8 @@ void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len)
 	/* If we expect an interrupt for the next entry, tell host
 	 * by writing event index and flush out the write before
 	 * the read in the next get_buf call. */
-	if (!(vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)) {
-		vring_used_event(&vq->vring) = vq->last_used_idx;
+	if (!(vq->vring.avail->flags & cpu_to_virtio16(_vq->vdev, VRING_AVAIL_F_NO_INTERRUPT))) {
+		vring_used_event(&vq->vring) = cpu_to_virtio16(_vq->vdev, vq->last_used_idx);
 		virtio_mb(vq->weak_barriers);
 	}
 
@@ -537,7 +538,7 @@ void virtqueue_disable_cb(struct virtqueue *_vq)
 {
 	struct vring_virtqueue *vq = to_vvq(_vq);
 
-	vq->vring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
+	vq->vring.avail->flags |= cpu_to_virtio16(_vq->vdev, VRING_AVAIL_F_NO_INTERRUPT);
 }
 EXPORT_SYMBOL_GPL(virtqueue_disable_cb);
 
@@ -565,8 +566,8 @@ unsigned virtqueue_enable_cb_prepare(struct virtqueue *_vq)
 	/* Depending on the VIRTIO_RING_F_EVENT_IDX feature, we need to
 	 * either clear the flags bit or point the event index at the next
 	 * entry. Always do both to keep code simple. */
-	vq->vring.avail->flags &= ~VRING_AVAIL_F_NO_INTERRUPT;
-	vring_used_event(&vq->vring) = last_used_idx = vq->last_used_idx;
+	vq->vring.avail->flags &= cpu_to_virtio16(_vq->vdev, ~VRING_AVAIL_F_NO_INTERRUPT);
+	vring_used_event(&vq->vring) = cpu_to_virtio16(_vq->vdev, last_used_idx = vq->last_used_idx);
 	END_USE(vq);
 	return last_used_idx;
 }
@@ -586,7 +587,7 @@ bool virtqueue_poll(struct virtqueue *_vq, unsigned last_used_idx)
 	struct vring_virtqueue *vq = to_vvq(_vq);
 
 	virtio_mb(vq->weak_barriers);
-	return (u16)last_used_idx != vq->vring.used->idx;
+	return (u16)last_used_idx != virtio16_to_cpu(_vq->vdev, vq->vring.used->idx);
 }
 EXPORT_SYMBOL_GPL(virtqueue_poll);
 
@@ -633,12 +634,12 @@ bool virtqueue_enable_cb_delayed(struct virtqueue *_vq)
 	/* Depending on the VIRTIO_RING_F_USED_EVENT_IDX feature, we need to
 	 * either clear the flags bit or point the event index at the next
 	 * entry. Always do both to keep code simple. */
-	vq->vring.avail->flags &= ~VRING_AVAIL_F_NO_INTERRUPT;
+	vq->vring.avail->flags &= cpu_to_virtio16(_vq->vdev, ~VRING_AVAIL_F_NO_INTERRUPT);
 	/* TODO: tune this threshold */
-	bufs = (u16)(vq->vring.avail->idx - vq->last_used_idx) * 3 / 4;
-	vring_used_event(&vq->vring) = vq->last_used_idx + bufs;
+	bufs = (u16)(virtio16_to_cpu(_vq->vdev, vq->vring.avail->idx) - vq->last_used_idx) * 3 / 4;
+	vring_used_event(&vq->vring) = cpu_to_virtio16(_vq->vdev, vq->last_used_idx + bufs);
 	virtio_mb(vq->weak_barriers);
-	if (unlikely((u16)(vq->vring.used->idx - vq->last_used_idx) > bufs)) {
+	if (unlikely((u16)(virtio16_to_cpu(_vq->vdev, vq->vring.used->idx) - vq->last_used_idx) > bufs)) {
 		END_USE(vq);
 		return false;
 	}
@@ -670,7 +671,7 @@ void *virtqueue_detach_unused_buf(struct virtqueue *_vq)
 		/* detach_buf clears data, so grab it now. */
 		buf = vq->data[i];
 		detach_buf(vq, i);
-		vq->vring.avail->idx--;
+		vq->vring.avail->idx = cpu_to_virtio16(_vq->vdev, virtio16_to_cpu(_vq->vdev, vq->vring.avail->idx) - 1);
 		END_USE(vq);
 		return buf;
 	}
@@ -747,12 +748,12 @@ struct virtqueue *vring_new_virtqueue(unsigned int index,
 
 	/* No callback?  Tell other side not to bother us. */
 	if (!callback)
-		vq->vring.avail->flags |= VRING_AVAIL_F_NO_INTERRUPT;
+		vq->vring.avail->flags |= cpu_to_virtio16(vdev, VRING_AVAIL_F_NO_INTERRUPT);
 
 	/* Put everything in free lists. */
 	vq->free_head = 0;
 	for (i = 0; i < num-1; i++) {
-		vq->vring.desc[i].next = i+1;
+		vq->vring.desc[i].next = cpu_to_virtio16(vdev, i + 1);
 		vq->data[i] = NULL;
 	}
 	vq->data[i] = NULL;
-- 
MST

[PATCH RFC v2 03/16] virtio: use u32, not bitmap for struct virtio_device's features

[Michael S. Tsirkin]

From: Rusty Russell <rusty@rustcorp.com.au>

It seemed like a good idea, but it's actually a pain when we get more
than 32 feature bits.  Just change it to a u32 for now.

Cc: Brian Swetland <swetland@google.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: Pawel Moll <pawel.moll@arm.com>
Acked-by: Ohad Ben-Cohen <ohad@wizery.com>

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/linux/virtio.h                 |  3 +--
 include/linux/virtio_config.h          |  2 +-
 tools/virtio/linux/virtio.h            | 22 +---------------------
 tools/virtio/linux/virtio_config.h     |  2 +-
 drivers/char/virtio_console.c          |  2 +-
 drivers/lguest/lguest_device.c         |  8 ++++----
 drivers/remoteproc/remoteproc_virtio.c |  2 +-
 drivers/s390/kvm/kvm_virtio.c          |  2 +-
 drivers/s390/kvm/virtio_ccw.c          | 23 +++++++++--------------
 drivers/virtio/virtio.c                | 10 +++++-----
 drivers/virtio/virtio_mmio.c           |  8 ++------
 drivers/virtio/virtio_pci.c            |  3 +--
 drivers/virtio/virtio_ring.c           |  2 +-
 tools/virtio/virtio_test.c             |  5 ++---
 tools/virtio/vringh_test.c             | 16 ++++++++--------
 15 files changed, 39 insertions(+), 71 deletions(-)

diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 65261a7..7828a7f 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -101,8 +101,7 @@ struct virtio_device {
 	const struct virtio_config_ops *config;
 	const struct vringh_config_ops *vringh_config;
 	struct list_head vqs;
-	/* Note that this is a Linux set_bit-style bitmap. */
-	unsigned long features[1];
+	u32 features;
 	void *priv;
 };
 
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index d38d3c2..946bed7 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -94,7 +94,7 @@ static inline bool virtio_has_feature(const struct virtio_device *vdev,
 	if (fbit < VIRTIO_TRANSPORT_F_START)
 		virtio_check_driver_offered_feature(vdev, fbit);
 
-	return test_bit(fbit, vdev->features);
+	return vdev->features & (1 << fbit);
 }
 
 static inline
diff --git a/tools/virtio/linux/virtio.h b/tools/virtio/linux/virtio.h
index 5a2d1f0..72bff70 100644
--- a/tools/virtio/linux/virtio.h
+++ b/tools/virtio/linux/virtio.h
@@ -6,31 +6,11 @@
 /* TODO: empty stubs for now. Broken but enough for virtio_ring.c */
 #define list_add_tail(a, b) do {} while (0)
 #define list_del(a) do {} while (0)
-
-#define BIT_WORD(nr)		((nr) / BITS_PER_LONG)
-#define BITS_PER_BYTE		8
-#define BITS_PER_LONG (sizeof(long) * BITS_PER_BYTE)
-#define BIT_MASK(nr)		(1UL << ((nr) % BITS_PER_LONG))
-
-/* TODO: Not atomic as it should be:
- * we don't use this for anything important. */
-static inline void clear_bit(int nr, volatile unsigned long *addr)
-{
-	unsigned long mask = BIT_MASK(nr);
-	unsigned long *p = ((unsigned long *)addr) + BIT_WORD(nr);
-
-	*p &= ~mask;
-}
-
-static inline int test_bit(int nr, const volatile unsigned long *addr)
-{
-        return 1UL & (addr[BIT_WORD(nr)] >> (nr & (BITS_PER_LONG-1)));
-}
 /* end of stubs */
 
 struct virtio_device {
 	void *dev;
-	unsigned long features[1];
+	u32 features;
 };
 
 struct virtqueue {
diff --git a/tools/virtio/linux/virtio_config.h b/tools/virtio/linux/virtio_config.h
index 5049967..1f1636b 100644
--- a/tools/virtio/linux/virtio_config.h
+++ b/tools/virtio/linux/virtio_config.h
@@ -2,5 +2,5 @@
 #define VIRTIO_TRANSPORT_F_END		32
 
 #define virtio_has_feature(dev, feature) \
-	test_bit((feature), (dev)->features)
+	((dev)->features & (1 << feature))
 
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index bfa6400..d79baf0 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -355,7 +355,7 @@ static inline bool use_multiport(struct ports_device *portdev)
 	 */
 	if (!portdev->vdev)
 		return 0;
-	return portdev->vdev->features[0] & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
+	return portdev->vdev->features & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
 }
 
 static DEFINE_SPINLOCK(dma_bufs_lock);
diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c
index d0a1d8a..c831c47 100644
--- a/drivers/lguest/lguest_device.c
+++ b/drivers/lguest/lguest_device.c
@@ -137,14 +137,14 @@ static void lg_finalize_features(struct virtio_device *vdev)
 	vring_transport_features(vdev);
 
 	/*
-	 * The vdev->feature array is a Linux bitmask: this isn't the same as a
-	 * the simple array of bits used by lguest devices for features.  So we
-	 * do this slow, manual conversion which is completely general.
+	 * Since lguest is currently x86-only, we're little-endian.  That
+	 * means we could just memcpy.  But it's not time critical, and in
+	 * case someone copies this code, we do it the slow, obvious way.
 	 */
 	memset(out_features, 0, desc->feature_len);
 	bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;
 	for (i = 0; i < bits; i++) {
-		if (test_bit(i, vdev->features))
+		if (vdev->features & (1 << i))
 			out_features[i / 8] |= (1 << (i % 8));
 	}
 
diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
index a34b506..dafaf38 100644
--- a/drivers/remoteproc/remoteproc_virtio.c
+++ b/drivers/remoteproc/remoteproc_virtio.c
@@ -231,7 +231,7 @@ static void rproc_virtio_finalize_features(struct virtio_device *vdev)
 	 * Remember the finalized features of our vdev, and provide it
 	 * to the remote processor once it is powered on.
 	 */
-	rsc->gfeatures = vdev->features[0];
+	rsc->gfeatures = vdev->features;
 }
 
 static void rproc_virtio_get(struct virtio_device *vdev, unsigned offset,
diff --git a/drivers/s390/kvm/kvm_virtio.c b/drivers/s390/kvm/kvm_virtio.c
index 6431290..ac79a09 100644
--- a/drivers/s390/kvm/kvm_virtio.c
+++ b/drivers/s390/kvm/kvm_virtio.c
@@ -106,7 +106,7 @@ static void kvm_finalize_features(struct virtio_device *vdev)
 	memset(out_features, 0, desc->feature_len);
 	bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;
 	for (i = 0; i < bits; i++) {
-		if (test_bit(i, vdev->features))
+		if (vdev->features & (1 << i))
 			out_features[i / 8] |= (1 << (i % 8));
 	}
 }
diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index 6cbe6ef..9ffd96f 100644
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -701,7 +701,6 @@ static void virtio_ccw_finalize_features(struct virtio_device *vdev)
 {
 	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
 	struct virtio_feature_desc *features;
-	int i;
 	struct ccw1 *ccw;
 
 	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
@@ -715,19 +714,15 @@ static void virtio_ccw_finalize_features(struct virtio_device *vdev)
 	/* Give virtio_ring a chance to accept features. */
 	vring_transport_features(vdev);
 
-	for (i = 0; i < sizeof(*vdev->features) / sizeof(features->features);
-	     i++) {
-		int highbits = i % 2 ? 32 : 0;
-		features->index = i;
-		features->features = cpu_to_le32(vdev->features[i / 2]
-						 >> highbits);
-		/* Write the feature bits to the host. */
-		ccw->cmd_code = CCW_CMD_WRITE_FEAT;
-		ccw->flags = 0;
-		ccw->count = sizeof(*features);
-		ccw->cda = (__u32)(unsigned long)features;
-		ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);
-	}
+	features->index = 0;
+	features->features = cpu_to_le32(vdev->features);
+	/* Write the feature bits to the host. */
+	ccw->cmd_code = CCW_CMD_WRITE_FEAT;
+	ccw->flags = 0;
+	ccw->count = sizeof(*features);
+	ccw->cda = (__u32)(unsigned long)features;
+	ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);
+
 out_free:
 	kfree(features);
 	kfree(ccw);
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index df598dd..7814b1f 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -49,9 +49,9 @@ static ssize_t features_show(struct device *_d,
 
 	/* We actually represent this as a bitstring, as it could be
 	 * arbitrary length in future. */
-	for (i = 0; i < ARRAY_SIZE(dev->features)*BITS_PER_LONG; i++)
+	for (i = 0; i < sizeof(dev->features)*8; i++)
 		len += sprintf(buf+len, "%c",
-			       test_bit(i, dev->features) ? '1' : '0');
+			       dev->features & (1ULL << i) ? '1' : '0');
 	len += sprintf(buf+len, "\n");
 	return len;
 }
@@ -168,18 +168,18 @@ static int virtio_dev_probe(struct device *_d)
 	device_features = dev->config->get_features(dev);
 
 	/* Features supported by both device and driver into dev->features. */
-	memset(dev->features, 0, sizeof(dev->features));
+	dev->features = 0;
 	for (i = 0; i < drv->feature_table_size; i++) {
 		unsigned int f = drv->feature_table[i];
 		BUG_ON(f >= 32);
 		if (device_features & (1 << f))
-			set_bit(f, dev->features);
+			dev->features |= (1 << f);
 	}
 
 	/* Transport features always preserved to pass to finalize_features. */
 	for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
 		if (device_features & (1 << i))
-			set_bit(i, dev->features);
+			dev->features |= (1 << i);
 
 	dev->config->finalize_features(dev);
 
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index ef9a165..eb5b0e2 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -155,16 +155,12 @@ static u32 vm_get_features(struct virtio_device *vdev)
 static void vm_finalize_features(struct virtio_device *vdev)
 {
 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
-	int i;
 
 	/* Give virtio_ring a chance to accept features. */
 	vring_transport_features(vdev);
 
-	for (i = 0; i < ARRAY_SIZE(vdev->features); i++) {
-		writel(i, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL);
-		writel(vdev->features[i],
-				vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
-	}
+	writel(0, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL);
+	writel(vdev->features, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
 }
 
 static void vm_get(struct virtio_device *vdev, unsigned offset,
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index d34ebfa..ab95a4c 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -120,8 +120,7 @@ static void vp_finalize_features(struct virtio_device *vdev)
 	vring_transport_features(vdev);
 
 	/* We only support 32 feature bits. */
-	BUILD_BUG_ON(ARRAY_SIZE(vdev->features) != 1);
-	iowrite32(vdev->features[0], vp_dev->ioaddr+VIRTIO_PCI_GUEST_FEATURES);
+	iowrite32(vdev->features, vp_dev->ioaddr+VIRTIO_PCI_GUEST_FEATURES);
 }
 
 /* virtio config->get() implementation */
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 048e1bc..ea1c02e 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -782,7 +782,7 @@ void vring_transport_features(struct virtio_device *vdev)
 			break;
 		default:
 			/* We don't understand this bit. */
-			clear_bit(i, vdev->features);
+			vdev->features &= ~(1 << i);
 		}
 	}
 }
diff --git a/tools/virtio/virtio_test.c b/tools/virtio/virtio_test.c
index 00ea679..db3437c 100644
--- a/tools/virtio/virtio_test.c
+++ b/tools/virtio/virtio_test.c
@@ -60,7 +60,7 @@ void vhost_vq_setup(struct vdev_info *dev, struct vq_info *info)
 {
 	struct vhost_vring_state state = { .index = info->idx };
 	struct vhost_vring_file file = { .index = info->idx };
-	unsigned long long features = dev->vdev.features[0];
+	unsigned long long features = dev->vdev.features;
 	struct vhost_vring_addr addr = {
 		.index = info->idx,
 		.desc_user_addr = (uint64_t)(unsigned long)info->vring.desc,
@@ -113,8 +113,7 @@ static void vdev_info_init(struct vdev_info* dev, unsigned long long features)
 {
 	int r;
 	memset(dev, 0, sizeof *dev);
-	dev->vdev.features[0] = features;
-	dev->vdev.features[1] = features >> 32;
+	dev->vdev.features = features;
 	dev->buf_size = 1024;
 	dev->buf = malloc(dev->buf_size);
 	assert(dev->buf);
diff --git a/tools/virtio/vringh_test.c b/tools/virtio/vringh_test.c
index 14a4f4c..b6c9ee3 100644
--- a/tools/virtio/vringh_test.c
+++ b/tools/virtio/vringh_test.c
@@ -304,7 +304,7 @@ static int parallel_test(unsigned long features,
 		close(to_guest[1]);
 		close(to_host[0]);
 
-		gvdev.vdev.features[0] = features;
+		gvdev.vdev.features = features;
 		gvdev.to_host_fd = to_host[1];
 		gvdev.notifies = 0;
 
@@ -449,13 +449,13 @@ int main(int argc, char *argv[])
 	bool fast_vringh = false, parallel = false;
 
 	getrange = getrange_iov;
-	vdev.features[0] = 0;
+	vdev.features = 0;
 
 	while (argv[1]) {
 		if (strcmp(argv[1], "--indirect") == 0)
-			vdev.features[0] |= (1 << VIRTIO_RING_F_INDIRECT_DESC);
+			vdev.features |= (1 << VIRTIO_RING_F_INDIRECT_DESC);
 		else if (strcmp(argv[1], "--eventidx") == 0)
-			vdev.features[0] |= (1 << VIRTIO_RING_F_EVENT_IDX);
+			vdev.features |= (1 << VIRTIO_RING_F_EVENT_IDX);
 		else if (strcmp(argv[1], "--slow-range") == 0)
 			getrange = getrange_slow;
 		else if (strcmp(argv[1], "--fast-vringh") == 0)
@@ -468,7 +468,7 @@ int main(int argc, char *argv[])
 	}
 
 	if (parallel)
-		return parallel_test(vdev.features[0], getrange, fast_vringh);
+		return parallel_test(vdev.features, getrange, fast_vringh);
 
 	if (posix_memalign(&__user_addr_min, PAGE_SIZE, USER_MEM) != 0)
 		abort();
@@ -483,7 +483,7 @@ int main(int argc, char *argv[])
 
 	/* Set up host side. */
 	vring_init(&vrh.vring, RINGSIZE, __user_addr_min, ALIGN);
-	vringh_init_user(&vrh, vdev.features[0], RINGSIZE, true,
+	vringh_init_user(&vrh, vdev.features, RINGSIZE, true,
 			 vrh.vring.desc, vrh.vring.avail, vrh.vring.used);
 
 	/* No descriptor to get yet... */
@@ -652,13 +652,13 @@ int main(int argc, char *argv[])
 	}
 
 	/* Test weird (but legal!) indirect. */
-	if (vdev.features[0] & (1 << VIRTIO_RING_F_INDIRECT_DESC)) {
+	if (vdev.features & (1 << VIRTIO_RING_F_INDIRECT_DESC)) {
 		char *data = __user_addr_max - USER_MEM/4;
 		struct vring_desc *d = __user_addr_max - USER_MEM/2;
 		struct vring vring;
 
 		/* Force creation of direct, which we modify. */
-		vdev.features[0] &= ~(1 << VIRTIO_RING_F_INDIRECT_DESC);
+		vdev.features &= ~(1 << VIRTIO_RING_F_INDIRECT_DESC);
 		vq = vring_new_virtqueue(0, RINGSIZE, ALIGN, &vdev, true,
 					 __user_addr_min,
 					 never_notify_host,
-- 
MST

[PATCH RFC v2 04/16] virtio: add support for 64 bit features.

[Michael S. Tsirkin]

From: Rusty Russell <rusty@rustcorp.com.au>

Change the u32 to a u64, and make sure to use 1ULL everywhere!

Cc: Brian Swetland <swetland@google.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
[Thomas Huth: fix up virtio-ccw get_features]
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Acked-by: Pawel Moll <pawel.moll@arm.com>
Acked-by: Ohad Ben-Cohen <ohad@wizery.com>

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/linux/virtio.h                 |  2 +-
 include/linux/virtio_config.h          |  8 ++++----
 tools/virtio/linux/virtio.h            |  2 +-
 tools/virtio/linux/virtio_config.h     |  2 +-
 drivers/char/virtio_console.c          |  2 +-
 drivers/lguest/lguest_device.c         | 10 +++++-----
 drivers/remoteproc/remoteproc_virtio.c |  5 ++++-
 drivers/s390/kvm/kvm_virtio.c          | 10 +++++-----
 drivers/s390/kvm/virtio_ccw.c          | 29 ++++++++++++++++++++++++-----
 drivers/virtio/virtio.c                | 12 ++++++------
 drivers/virtio/virtio_mmio.c           | 14 +++++++++-----
 drivers/virtio/virtio_pci.c            |  5 ++---
 drivers/virtio/virtio_ring.c           |  2 +-
 13 files changed, 64 insertions(+), 39 deletions(-)

diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 7828a7f..149284e 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -101,7 +101,7 @@ struct virtio_device {
 	const struct virtio_config_ops *config;
 	const struct vringh_config_ops *vringh_config;
 	struct list_head vqs;
-	u32 features;
+	u64 features;
 	void *priv;
 };
 
diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index 946bed7..7d46280 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -67,7 +67,7 @@ struct virtio_config_ops {
 			vq_callback_t *callbacks[],
 			const char *names[]);
 	void (*del_vqs)(struct virtio_device *);
-	u32 (*get_features)(struct virtio_device *vdev);
+	u64 (*get_features)(struct virtio_device *vdev);
 	void (*finalize_features)(struct virtio_device *vdev);
 	const char *(*bus_name)(struct virtio_device *vdev);
 	int (*set_vq_affinity)(struct virtqueue *vq, int cpu);
@@ -87,14 +87,14 @@ static inline bool virtio_has_feature(const struct virtio_device *vdev,
 {
 	/* Did you forget to fix assumptions on max features? */
 	if (__builtin_constant_p(fbit))
-		BUILD_BUG_ON(fbit >= 32);
+		BUILD_BUG_ON(fbit >= 64);
 	else
-		BUG_ON(fbit >= 32);
+		BUG_ON(fbit >= 64);
 
 	if (fbit < VIRTIO_TRANSPORT_F_START)
 		virtio_check_driver_offered_feature(vdev, fbit);
 
-	return vdev->features & (1 << fbit);
+	return vdev->features & (1ULL << fbit);
 }
 
 static inline
diff --git a/tools/virtio/linux/virtio.h b/tools/virtio/linux/virtio.h
index 72bff70..8eb6421 100644
--- a/tools/virtio/linux/virtio.h
+++ b/tools/virtio/linux/virtio.h
@@ -10,7 +10,7 @@
 
 struct virtio_device {
 	void *dev;
-	u32 features;
+	u64 features;
 };
 
 struct virtqueue {
diff --git a/tools/virtio/linux/virtio_config.h b/tools/virtio/linux/virtio_config.h
index 1f1636b..a254c2b 100644
--- a/tools/virtio/linux/virtio_config.h
+++ b/tools/virtio/linux/virtio_config.h
@@ -2,5 +2,5 @@
 #define VIRTIO_TRANSPORT_F_END		32
 
 #define virtio_has_feature(dev, feature) \
-	((dev)->features & (1 << feature))
+	((dev)->features & (1ULL << feature))
 
diff --git a/drivers/char/virtio_console.c b/drivers/char/virtio_console.c
index d79baf0..1690b2a 100644
--- a/drivers/char/virtio_console.c
+++ b/drivers/char/virtio_console.c
@@ -355,7 +355,7 @@ static inline bool use_multiport(struct ports_device *portdev)
 	 */
 	if (!portdev->vdev)
 		return 0;
-	return portdev->vdev->features & (1 << VIRTIO_CONSOLE_F_MULTIPORT);
+	return portdev->vdev->features & (1ULL << VIRTIO_CONSOLE_F_MULTIPORT);
 }
 
 static DEFINE_SPINLOCK(dma_bufs_lock);
diff --git a/drivers/lguest/lguest_device.c b/drivers/lguest/lguest_device.c
index c831c47..4d29bcd 100644
--- a/drivers/lguest/lguest_device.c
+++ b/drivers/lguest/lguest_device.c
@@ -94,17 +94,17 @@ static unsigned desc_size(const struct lguest_device_desc *desc)
 }
 
 /* This gets the device's feature bits. */
-static u32 lg_get_features(struct virtio_device *vdev)
+static u64 lg_get_features(struct virtio_device *vdev)
 {
 	unsigned int i;
-	u32 features = 0;
+	u64 features = 0;
 	struct lguest_device_desc *desc = to_lgdev(vdev)->desc;
 	u8 *in_features = lg_features(desc);
 
 	/* We do this the slow but generic way. */
-	for (i = 0; i < min(desc->feature_len * 8, 32); i++)
+	for (i = 0; i < min(desc->feature_len * 8, 64); i++)
 		if (in_features[i / 8] & (1 << (i % 8)))
-			features |= (1 << i);
+			features |= (1ULL << i);
 
 	return features;
 }
@@ -144,7 +144,7 @@ static void lg_finalize_features(struct virtio_device *vdev)
 	memset(out_features, 0, desc->feature_len);
 	bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;
 	for (i = 0; i < bits; i++) {
-		if (vdev->features & (1 << i))
+		if (vdev->features & (1ULL << i))
 			out_features[i / 8] |= (1 << (i % 8));
 	}
 
diff --git a/drivers/remoteproc/remoteproc_virtio.c b/drivers/remoteproc/remoteproc_virtio.c
index dafaf38..627737e 100644
--- a/drivers/remoteproc/remoteproc_virtio.c
+++ b/drivers/remoteproc/remoteproc_virtio.c
@@ -207,7 +207,7 @@ static void rproc_virtio_reset(struct virtio_device *vdev)
 }
 
 /* provide the vdev features as retrieved from the firmware */
-static u32 rproc_virtio_get_features(struct virtio_device *vdev)
+static u64 rproc_virtio_get_features(struct virtio_device *vdev)
 {
 	struct rproc_vdev *rvdev = vdev_to_rvdev(vdev);
 	struct fw_rsc_vdev *rsc;
@@ -227,6 +227,9 @@ static void rproc_virtio_finalize_features(struct virtio_device *vdev)
 	/* Give virtio_ring a chance to accept features */
 	vring_transport_features(vdev);
 
+	/* Make sure we don't have any features > 32 bits! */
+	BUG_ON((u32)vdev->features != vdev->features);
+
 	/*
 	 * Remember the finalized features of our vdev, and provide it
 	 * to the remote processor once it is powered on.
diff --git a/drivers/s390/kvm/kvm_virtio.c b/drivers/s390/kvm/kvm_virtio.c
index ac79a09..c78251d 100644
--- a/drivers/s390/kvm/kvm_virtio.c
+++ b/drivers/s390/kvm/kvm_virtio.c
@@ -80,16 +80,16 @@ static unsigned desc_size(const struct kvm_device_desc *desc)
 }
 
 /* This gets the device's feature bits. */
-static u32 kvm_get_features(struct virtio_device *vdev)
+static u64 kvm_get_features(struct virtio_device *vdev)
 {
 	unsigned int i;
-	u32 features = 0;
+	u64 features = 0;
 	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
 	u8 *in_features = kvm_vq_features(desc);
 
-	for (i = 0; i < min(desc->feature_len * 8, 32); i++)
+	for (i = 0; i < min(desc->feature_len * 8, 64); i++)
 		if (in_features[i / 8] & (1 << (i % 8)))
-			features |= (1 << i);
+			features |= (1ULL << i);
 	return features;
 }
 
@@ -106,7 +106,7 @@ static void kvm_finalize_features(struct virtio_device *vdev)
 	memset(out_features, 0, desc->feature_len);
 	bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;
 	for (i = 0; i < bits; i++) {
-		if (vdev->features & (1 << i))
+		if (vdev->features & (1ULL << i))
 			out_features[i / 8] |= (1 << (i % 8));
 	}
 }
diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index 9ffd96f..27aab69 100644
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -660,11 +660,12 @@ static void virtio_ccw_reset(struct virtio_device *vdev)
 	kfree(ccw);
 }
 
-static u32 virtio_ccw_get_features(struct virtio_device *vdev)
+static u64 virtio_ccw_get_features(struct virtio_device *vdev)
 {
 	struct virtio_ccw_device *vcdev = to_vc_device(vdev);
 	struct virtio_feature_desc *features;
-	int ret, rc;
+	int ret;
+	u64 rc;
 	struct ccw1 *ccw;
 
 	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
@@ -677,7 +678,6 @@ static u32 virtio_ccw_get_features(struct virtio_device *vdev)
 		goto out_free;
 	}
 	/* Read the feature bits from the host. */
-	/* TODO: Features > 32 bits */
 	features->index = 0;
 	ccw->cmd_code = CCW_CMD_READ_FEAT;
 	ccw->flags = 0;
@@ -691,6 +691,16 @@ static u32 virtio_ccw_get_features(struct virtio_device *vdev)
 
 	rc = le32_to_cpu(features->features);
 
+	/* Read second half feature bits from the host. */
+	features->index = 1;
+	ccw->cmd_code = CCW_CMD_READ_FEAT;
+	ccw->flags = 0;
+	ccw->count = sizeof(*features);
+	ccw->cda = (__u32)(unsigned long)features;
+	ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_READ_FEAT);
+	if (ret == 0)
+		rc |= (u64)le32_to_cpu(features->features) << 32;
+
 out_free:
 	kfree(features);
 	kfree(ccw);
@@ -715,8 +725,17 @@ static void virtio_ccw_finalize_features(struct virtio_device *vdev)
 	vring_transport_features(vdev);
 
 	features->index = 0;
-	features->features = cpu_to_le32(vdev->features);
-	/* Write the feature bits to the host. */
+	features->features = cpu_to_le32((u32)vdev->features);
+	/* Write the first half of the feature bits to the host. */
+	ccw->cmd_code = CCW_CMD_WRITE_FEAT;
+	ccw->flags = 0;
+	ccw->count = sizeof(*features);
+	ccw->cda = (__u32)(unsigned long)features;
+	ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_FEAT);
+
+	features->index = 1;
+	features->features = cpu_to_le32(vdev->features >> 32);
+	/* Write the second half of the feature bits to the host. */
 	ccw->cmd_code = CCW_CMD_WRITE_FEAT;
 	ccw->flags = 0;
 	ccw->count = sizeof(*features);
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index 7814b1f..d213567 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -159,7 +159,7 @@ static int virtio_dev_probe(struct device *_d)
 	int err, i;
 	struct virtio_device *dev = dev_to_virtio(_d);
 	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
-	u32 device_features;
+	u64 device_features;
 
 	/* We have a driver! */
 	add_status(dev, VIRTIO_CONFIG_S_DRIVER);
@@ -171,15 +171,15 @@ static int virtio_dev_probe(struct device *_d)
 	dev->features = 0;
 	for (i = 0; i < drv->feature_table_size; i++) {
 		unsigned int f = drv->feature_table[i];
-		BUG_ON(f >= 32);
-		if (device_features & (1 << f))
-			dev->features |= (1 << f);
+		BUG_ON(f >= 64);
+		if (device_features & (1ULL << f))
+			dev->features |= (1ULL << f);
 	}
 
 	/* Transport features always preserved to pass to finalize_features. */
 	for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++)
-		if (device_features & (1 << i))
-			dev->features |= (1 << i);
+		if (device_features & (1ULL << i))
+			dev->features |= (1ULL << i);
 
 	dev->config->finalize_features(dev);
 
diff --git a/drivers/virtio/virtio_mmio.c b/drivers/virtio/virtio_mmio.c
index eb5b0e2..fd01c6d 100644
--- a/drivers/virtio/virtio_mmio.c
+++ b/drivers/virtio/virtio_mmio.c
@@ -142,14 +142,16 @@ struct virtio_mmio_vq_info {
 
 /* Configuration interface */
 
-static u32 vm_get_features(struct virtio_device *vdev)
+static u64 vm_get_features(struct virtio_device *vdev)
 {
 	struct virtio_mmio_device *vm_dev = to_virtio_mmio_device(vdev);
+	u64 features;
 
-	/* TODO: Features > 32 bits */
 	writel(0, vm_dev->base + VIRTIO_MMIO_HOST_FEATURES_SEL);
-
-	return readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES);
+	features = readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES);
+	writel(1, vm_dev->base + VIRTIO_MMIO_HOST_FEATURES_SEL);
+	features |= ((u64)readl(vm_dev->base + VIRTIO_MMIO_HOST_FEATURES) << 32);
+	return features;
 }
 
 static void vm_finalize_features(struct virtio_device *vdev)
@@ -160,7 +162,9 @@ static void vm_finalize_features(struct virtio_device *vdev)
 	vring_transport_features(vdev);
 
 	writel(0, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL);
-	writel(vdev->features, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
+	writel((u32)vdev->features, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
+	writel(1, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES_SEL);
+	writel(vdev->features >> 32, vm_dev->base + VIRTIO_MMIO_GUEST_FEATURES);
 }
 
 static void vm_get(struct virtio_device *vdev, unsigned offset,
diff --git a/drivers/virtio/virtio_pci.c b/drivers/virtio/virtio_pci.c
index ab95a4c..68c0711 100644
--- a/drivers/virtio/virtio_pci.c
+++ b/drivers/virtio/virtio_pci.c
@@ -102,12 +102,11 @@ static struct virtio_pci_device *to_vp_device(struct virtio_device *vdev)
 }
 
 /* virtio config->get_features() implementation */
-static u32 vp_get_features(struct virtio_device *vdev)
+static u64 vp_get_features(struct virtio_device *vdev)
 {
 	struct virtio_pci_device *vp_dev = to_vp_device(vdev);
 
-	/* When someone needs more than 32 feature bits, we'll need to
-	 * steal a bit to indicate that the rest are somewhere else. */
+	/* We only support 32 feature bits. */
 	return ioread32(vp_dev->ioaddr + VIRTIO_PCI_HOST_FEATURES);
 }
 
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index ea1c02e..b311fa7 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -782,7 +782,7 @@ void vring_transport_features(struct virtio_device *vdev)
 			break;
 		default:
 			/* We don't understand this bit. */
-			vdev->features &= ~(1 << i);
+			vdev->features &= ~(1ULL << i);
 		}
 	}
 }
-- 
MST

[PATCH RFC v2 05/16] virtio: add virtio 1.0 feature bit

[Michael S. Tsirkin]

Based on original patches by Rusty Russell, Thomas Huth
and Cornelia Huck.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/uapi/linux/virtio_config.h | 7 +++++--
 drivers/virtio/virtio_ring.c       | 2 ++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h
index 3ce768c..f3fe33a 100644
--- a/include/uapi/linux/virtio_config.h
+++ b/include/uapi/linux/virtio_config.h
@@ -41,11 +41,11 @@
 /* We've given up on this device. */
 #define VIRTIO_CONFIG_S_FAILED		0x80
 
-/* Some virtio feature bits (currently bits 28 through 31) are reserved for the
+/* Some virtio feature bits (currently bits 28 through 32) are reserved for the
  * transport being used (eg. virtio_ring), the rest are per-device feature
  * bits. */
 #define VIRTIO_TRANSPORT_F_START	28
-#define VIRTIO_TRANSPORT_F_END		32
+#define VIRTIO_TRANSPORT_F_END		33
 
 /* Do we get callbacks when the ring is completely used, even if we've
  * suppressed them? */
@@ -54,4 +54,7 @@
 /* Can the device handle any descriptor layout? */
 #define VIRTIO_F_ANY_LAYOUT		27
 
+/* v1.0 compliant. */
+#define VIRTIO_F_VERSION_1		32
+
 #endif /* _UAPI_LINUX_VIRTIO_CONFIG_H */
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index b311fa7..9f5dfe3 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -780,6 +780,8 @@ void vring_transport_features(struct virtio_device *vdev)
 			break;
 		case VIRTIO_RING_F_EVENT_IDX:
 			break;
+		case VIRTIO_F_VERSION_1:
+			break;
 		default:
 			/* We don't understand this bit. */
 			vdev->features &= ~(1ULL << i);
-- 
MST

[PATCH RFC v2 06/16] virtio: make endian-ness depend on virtio 1.0

[Michael S. Tsirkin]

virtio 1.0 is LE, virtio without 1.0 is native endian.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/linux/virtio_config.h | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index 7d46280..be0f6dd 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -157,11 +157,11 @@ int virtqueue_set_affinity(struct virtqueue *vq, int cpu)
 #define DEFINE_VIRTIO_XX_TO_CPU(bits) \
 static inline u##bits virtio##bits##_to_cpu(struct virtio_device *vdev, __virtio##bits val) \
 { \
-	return __virtio##bits##_to_cpu(false, val); \
+	return __virtio##bits##_to_cpu(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val); \
 } \
 static inline __virtio##bits cpu_to_virtio##bits(struct virtio_device *vdev, u##bits val) \
 { \
-	return __cpu_to_virtio##bits(false, val); \
+	return __cpu_to_virtio##bits(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val); \
 }
 
 DEFINE_VIRTIO_XX_TO_CPU(16)
-- 
MST

[PATCH RFC v2 07/16] virtio_config: endian conversion for v1.0

[Michael S. Tsirkin]

We (ab)use virtio conversion functions for device-specific
config space accesses.

Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/linux/virtio_config.h | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/include/linux/virtio_config.h b/include/linux/virtio_config.h
index be0f6dd..09cd89c 100644
--- a/include/linux/virtio_config.h
+++ b/include/linux/virtio_config.h
@@ -255,12 +255,13 @@ static inline u16 virtio_cread16(struct virtio_device *vdev,
 {
 	u16 ret;
 	vdev->config->get(vdev, offset, &ret, sizeof(ret));
-	return ret;
+	return virtio16_to_cpu(vdev, (__force __virtio16)ret);
 }
 
 static inline void virtio_cwrite16(struct virtio_device *vdev,
 				   unsigned int offset, u16 val)
 {
+	val = (__force u16)cpu_to_virtio16(vdev, val);
 	vdev->config->set(vdev, offset, &val, sizeof(val));
 }
 
@@ -269,12 +270,13 @@ static inline u32 virtio_cread32(struct virtio_device *vdev,
 {
 	u32 ret;
 	vdev->config->get(vdev, offset, &ret, sizeof(ret));
-	return ret;
+	return virtio32_to_cpu(vdev, (__force __virtio32)ret);
 }
 
 static inline void virtio_cwrite32(struct virtio_device *vdev,
 				   unsigned int offset, u32 val)
 {
+	val = (__force u32)cpu_to_virtio32(vdev, val);
 	vdev->config->set(vdev, offset, &val, sizeof(val));
 }
 
@@ -283,12 +285,13 @@ static inline u64 virtio_cread64(struct virtio_device *vdev,
 {
 	u64 ret;
 	vdev->config->get(vdev, offset, &ret, sizeof(ret));
-	return ret;
+	return virtio64_to_cpu(vdev, (__force __virtio64)ret);
 }
 
 static inline void virtio_cwrite64(struct virtio_device *vdev,
 				   unsigned int offset, u64 val)
 {
+	val = (__force u64)cpu_to_virtio64(vdev, val);
 	vdev->config->set(vdev, offset, &val, sizeof(val));
 }
 
-- 
MST

[PATCH RFC v2 08/16] virtio: allow transports to get avail/used addresses

[Michael S. Tsirkin]

From: Cornelia Huck <cornelia.huck@de.ibm.com>

For virtio-1, we can theoretically have a more complex virtqueue
layout with avail and used buffers not on a contiguous memory area
with the descriptor table. For now, it's fine for a transport driver
to stay with the old layout: It needs, however, a way to access
the locations of the avail/used rings so it can register them with
the host.

Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/linux/virtio.h       |  3 +++
 drivers/virtio/virtio_ring.c | 16 ++++++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 149284e..d6359a5 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -75,6 +75,9 @@ unsigned int virtqueue_get_vring_size(struct virtqueue *vq);
 
 bool virtqueue_is_broken(struct virtqueue *vq);
 
+void *virtqueue_get_avail(struct virtqueue *vq);
+void *virtqueue_get_used(struct virtqueue *vq);
+
 /**
  * virtio_device - representation of a device using virtio
  * @index: unique position on the virtio bus
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 9f5dfe3..1db44ba 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -829,4 +829,20 @@ void virtio_break_device(struct virtio_device *dev)
 }
 EXPORT_SYMBOL_GPL(virtio_break_device);
 
+void *virtqueue_get_avail(struct virtqueue *_vq)
+{
+	struct vring_virtqueue *vq = to_vvq(_vq);
+
+	return vq->vring.avail;
+}
+EXPORT_SYMBOL_GPL(virtqueue_get_avail);
+
+void *virtqueue_get_used(struct virtqueue *_vq)
+{
+	struct vring_virtqueue *vq = to_vvq(_vq);
+
+	return vq->vring.used;
+}
+EXPORT_SYMBOL_GPL(virtqueue_get_used);
+
 MODULE_LICENSE("GPL");
-- 
MST

[PATCH RFC v2 09/16] virtio: set FEATURES_OK

[Michael S. Tsirkin]

set FEATURES_OK as per virtio 1.0 spec

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/uapi/linux/virtio_config.h |  2 ++
 drivers/virtio/virtio.c            | 29 ++++++++++++++++++++++-------
 2 files changed, 24 insertions(+), 7 deletions(-)

diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h
index f3fe33a..a6d0cde 100644
--- a/include/uapi/linux/virtio_config.h
+++ b/include/uapi/linux/virtio_config.h
@@ -38,6 +38,8 @@
 #define VIRTIO_CONFIG_S_DRIVER		2
 /* Driver has used its parts of the config, and is happy */
 #define VIRTIO_CONFIG_S_DRIVER_OK	4
+/* Driver has finished configuring features */
+#define VIRTIO_CONFIG_S_FEATURES_OK	8
 /* We've given up on this device. */
 #define VIRTIO_CONFIG_S_FAILED		0x80
 
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index d213567..a3df817 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -160,6 +160,7 @@ static int virtio_dev_probe(struct device *_d)
 	struct virtio_device *dev = dev_to_virtio(_d);
 	struct virtio_driver *drv = drv_to_virtio(dev->dev.driver);
 	u64 device_features;
+	unsigned status;
 
 	/* We have a driver! */
 	add_status(dev, VIRTIO_CONFIG_S_DRIVER);
@@ -183,18 +184,32 @@ static int virtio_dev_probe(struct device *_d)
 
 	dev->config->finalize_features(dev);
 
+	if (virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
+		add_status(dev, VIRTIO_CONFIG_S_FEATURES_OK);
+		status = dev->config->get_status(dev);
+		if (!(status & VIRTIO_CONFIG_S_FEATURES_OK)) {
+			printk(KERN_ERR "virtio: device refuses features: %x\n",
+			       status);
+			err = -ENODEV;
+			goto err;
+		}
+	}
+
 	err = drv->probe(dev);
 	if (err)
-		add_status(dev, VIRTIO_CONFIG_S_FAILED);
-	else {
-		add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
-		if (drv->scan)
-			drv->scan(dev);
+		goto err;
 
-		virtio_config_enable(dev);
-	}
+	add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK);
+	if (drv->scan)
+		drv->scan(dev);
+
+	virtio_config_enable(dev);
 
+	return 0;
+err:
+	add_status(dev, VIRTIO_CONFIG_S_FAILED);
 	return err;
+
 }
 
 static int virtio_dev_remove(struct device *_d)
-- 
MST

[PATCH RFC v2 10/16] virtio_net: use v1.0 endian.

[Michael S. Tsirkin]

From: Rusty Russell <rusty@rustcorp.com.au>

[Cornelia Huck: converted some missed fields]
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/net/virtio_net.c | 31 +++++++++++++++++++------------
 1 file changed, 19 insertions(+), 12 deletions(-)

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index d75256bd..2e6561e 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -347,13 +347,14 @@ err:
 }
 
 static struct sk_buff *receive_mergeable(struct net_device *dev,
+					 struct virtnet_info *vi,
 					 struct receive_queue *rq,
 					 unsigned long ctx,
 					 unsigned int len)
 {
 	void *buf = mergeable_ctx_to_buf_address(ctx);
 	struct skb_vnet_hdr *hdr = buf;
-	int num_buf = hdr->mhdr.num_buffers;
+	u16 num_buf = virtio16_to_cpu(rq->vq->vdev, hdr->mhdr.num_buffers);
 	struct page *page = virt_to_head_page(buf);
 	int offset = buf - page_address(page);
 	unsigned int truesize = max(len, mergeable_ctx_to_buf_truesize(ctx));
@@ -369,7 +370,9 @@ static struct sk_buff *receive_mergeable(struct net_device *dev,
 		ctx = (unsigned long)virtqueue_get_buf(rq->vq, &len);
 		if (unlikely(!ctx)) {
 			pr_debug("%s: rx error: %d buffers out of %d missing\n",
-				 dev->name, num_buf, hdr->mhdr.num_buffers);
+				 dev->name, num_buf,
+				 virtio16_to_cpu(rq->vq->vdev,
+						 hdr->mhdr.num_buffers));
 			dev->stats.rx_length_errors++;
 			goto err_buf;
 		}
@@ -454,7 +457,7 @@ static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
 	}
 
 	if (vi->mergeable_rx_bufs)
-		skb = receive_mergeable(dev, rq, (unsigned long)buf, len);
+		skb = receive_mergeable(dev, vi, rq, (unsigned long)buf, len);
 	else if (vi->big_packets)
 		skb = receive_big(dev, rq, buf, len);
 	else
@@ -473,8 +476,8 @@ static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
 	if (hdr->hdr.flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) {
 		pr_debug("Needs csum!\n");
 		if (!skb_partial_csum_set(skb,
-					  hdr->hdr.csum_start,
-					  hdr->hdr.csum_offset))
+			  virtio16_to_cpu(vi->vdev, hdr->hdr.csum_start),
+			  virtio16_to_cpu(vi->vdev, hdr->hdr.csum_offset)))
 			goto frame_err;
 	} else if (hdr->hdr.flags & VIRTIO_NET_HDR_F_DATA_VALID) {
 		skb->ip_summed = CHECKSUM_UNNECESSARY;
@@ -505,7 +508,8 @@ static void receive_buf(struct receive_queue *rq, void *buf, unsigned int len)
 		if (hdr->hdr.gso_type & VIRTIO_NET_HDR_GSO_ECN)
 			skb_shinfo(skb)->gso_type |= SKB_GSO_TCP_ECN;
 
-		skb_shinfo(skb)->gso_size = hdr->hdr.gso_size;
+		skb_shinfo(skb)->gso_size = virtio16_to_cpu(vi->vdev,
+							    hdr->hdr.gso_size);
 		if (skb_shinfo(skb)->gso_size == 0) {
 			net_warn_ratelimited("%s: zero gso size.\n", dev->name);
 			goto frame_err;
@@ -867,16 +871,19 @@ static int xmit_skb(struct send_queue *sq, struct sk_buff *skb)
 
 	if (skb->ip_summed == CHECKSUM_PARTIAL) {
 		hdr->hdr.flags = VIRTIO_NET_HDR_F_NEEDS_CSUM;
-		hdr->hdr.csum_start = skb_checksum_start_offset(skb);
-		hdr->hdr.csum_offset = skb->csum_offset;
+		hdr->hdr.csum_start = cpu_to_virtio16(vi->vdev,
+						skb_checksum_start_offset(skb));
+		hdr->hdr.csum_offset = cpu_to_virtio16(vi->vdev,
+							 skb->csum_offset);
 	} else {
 		hdr->hdr.flags = 0;
 		hdr->hdr.csum_offset = hdr->hdr.csum_start = 0;
 	}
 
 	if (skb_is_gso(skb)) {
-		hdr->hdr.hdr_len = skb_headlen(skb);
-		hdr->hdr.gso_size = skb_shinfo(skb)->gso_size;
+		hdr->hdr.hdr_len = cpu_to_virtio16(vi->vdev, skb_headlen(skb));
+		hdr->hdr.gso_size = cpu_to_virtio16(vi->vdev,
+						    skb_shinfo(skb)->gso_size);
 		if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV4)
 			hdr->hdr.gso_type = VIRTIO_NET_HDR_GSO_TCPV4;
 		else if (skb_shinfo(skb)->gso_type & SKB_GSO_TCPV6)
@@ -1182,7 +1189,7 @@ static void virtnet_set_rx_mode(struct net_device *dev)
 	sg_init_table(sg, 2);
 
 	/* Store the unicast list and count in the front of the buffer */
-	mac_data->entries = uc_count;
+	mac_data->entries = cpu_to_virtio32(vi->vdev, uc_count);
 	i = 0;
 	netdev_for_each_uc_addr(ha, dev)
 		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
@@ -1193,7 +1200,7 @@ static void virtnet_set_rx_mode(struct net_device *dev)
 	/* multicast list and count fill the end */
 	mac_data = (void *)&mac_data->macs[uc_count][0];
 
-	mac_data->entries = mc_count;
+	mac_data->entries = cpu_to_virtio32(vi->vdev, mc_count);
 	i = 0;
 	netdev_for_each_mc_addr(ha, dev)
 		memcpy(&mac_data->macs[i++][0], ha->addr, ETH_ALEN);
-- 
MST

[PATCH RFC v2 11/16] virtio_blk: use virtio v1.0 endian

[Michael S. Tsirkin]

From: Cornelia Huck <cornelia.huck@de.ibm.com>

Note that we care only about the fields still in use for virtio v1.0.

Reviewed-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/block/virtio_blk.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index c6a27d5..327e601 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -113,6 +113,10 @@ static int __virtblk_add_req(struct virtqueue *vq,
 	sg_init_one(&status, &vbr->status, sizeof(vbr->status));
 	sgs[num_out + num_in++] = &status;
 
+	/* we only care about fields valid for virtio-1 */
+	vbr->out_hdr.type = cpu_to_virtio32(vq->vdev, vbr->out_hdr.type);
+	vbr->out_hdr.sector = cpu_to_virtio64(vq->vdev, vbr->out_hdr.sector);
+
 	return virtqueue_add_sgs(vq, sgs, num_out, num_in, vbr, GFP_ATOMIC);
 }
 
-- 
MST

[PATCH RFC v2 15/16] virtio_net: fix types for in memory structures

[Michael S. Tsirkin]

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/uapi/linux/virtio_net.h | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/include/uapi/linux/virtio_net.h b/include/uapi/linux/virtio_net.h
index 172a7f0..b5f1677 100644
--- a/include/uapi/linux/virtio_net.h
+++ b/include/uapi/linux/virtio_net.h
@@ -28,6 +28,7 @@
 #include <linux/types.h>
 #include <linux/virtio_ids.h>
 #include <linux/virtio_config.h>
+#include <linux/virtio_types.h>
 #include <linux/if_ether.h>
 
 /* The feature bitmap for virtio net */
@@ -84,17 +85,17 @@ struct virtio_net_hdr {
 #define VIRTIO_NET_HDR_GSO_TCPV6	4	// GSO frame, IPv6 TCP
 #define VIRTIO_NET_HDR_GSO_ECN		0x80	// TCP has ECN set
 	__u8 gso_type;
-	__u16 hdr_len;		/* Ethernet + IP + tcp/udp hdrs */
-	__u16 gso_size;		/* Bytes to append to hdr_len per frame */
-	__u16 csum_start;	/* Position to start checksumming from */
-	__u16 csum_offset;	/* Offset after that to place checksum */
+	__virtio16 hdr_len;		/* Ethernet + IP + tcp/udp hdrs */
+	__virtio16 gso_size;		/* Bytes to append to hdr_len per frame */
+	__virtio16 csum_start;	/* Position to start checksumming from */
+	__virtio16 csum_offset;	/* Offset after that to place checksum */
 };
 
 /* This is the version of the header to use when the MRG_RXBUF
  * feature has been negotiated. */
 struct virtio_net_hdr_mrg_rxbuf {
 	struct virtio_net_hdr hdr;
-	__u16 num_buffers;	/* Number of merged rx buffers */
+	__virtio16 num_buffers;	/* Number of merged rx buffers */
 };
 
 /*
@@ -149,7 +150,7 @@ typedef __u8 virtio_net_ctrl_ack;
  * VIRTIO_NET_F_CTRL_MAC_ADDR feature is available.
  */
 struct virtio_net_ctrl_mac {
-	__u32 entries;
+	__virtio32 entries;
 	__u8 macs[][ETH_ALEN];
 } __attribute__((packed));
 
@@ -193,7 +194,7 @@ struct virtio_net_ctrl_mac {
  * specified.
  */
 struct virtio_net_ctrl_mq {
-	__u16 virtqueue_pairs;
+	__virtio16 virtqueue_pairs;
 };
 
 #define VIRTIO_NET_CTRL_MQ   4
-- 
MST

[PATCH RFC v2 16/16] virtio_blk: fix types for in memory structures

[Michael S. Tsirkin]

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 include/uapi/linux/virtio_blk.h | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/include/uapi/linux/virtio_blk.h b/include/uapi/linux/virtio_blk.h
index 9ad67b2..247c8ba 100644
--- a/include/uapi/linux/virtio_blk.h
+++ b/include/uapi/linux/virtio_blk.h
@@ -28,6 +28,7 @@
 #include <linux/types.h>
 #include <linux/virtio_ids.h>
 #include <linux/virtio_config.h>
+#include <linux/virtio_types.h>
 
 /* Feature bits */
 #define VIRTIO_BLK_F_BARRIER	0	/* Does host support barriers? */
@@ -114,18 +115,18 @@ struct virtio_blk_config {
 /* This is the first element of the read scatter-gather list. */
 struct virtio_blk_outhdr {
 	/* VIRTIO_BLK_T* */
-	__u32 type;
+	__virtio32 type;
 	/* io priority. */
-	__u32 ioprio;
+	__virtio32 ioprio;
 	/* Sector (ie. 512 byte offset) */
-	__u64 sector;
+	__virtio64 sector;
 };
 
 struct virtio_scsi_inhdr {
-	__u32 errors;
-	__u32 data_len;
-	__u32 sense_len;
-	__u32 residual;
+	__virtio32 errors;
+	__virtio32 data_len;
+	__virtio32 sense_len;
+	__virtio32 residual;
 };
 
 /* And this is the final byte of the write scatter-gather list. */
-- 
MST