[PATCH RFC v3 00/16] linux: towards virtio-1 guest support

[PATCH RFC v3 00/16] linux: towards virtio-1 guest support

[Michael S. Tsirkin]

Based on patches by Cornelia and others, but
with an API that should allow better static checking of code,
and slightly more concervative changes in vring.

Changes from v2:
	add missing virtio_byteorder.h

Cornelia Huck (4):
  virtio: allow transports to get avail/used addresses
  virtio_blk: use virtio v1.0 endian
  KVM: s390: virtio-ccw revision 1 SET_VQ
  KVM: s390: enable virtio-ccw revision 1

Michael S. Tsirkin (8):
  virtio: memory access APIs
  virtio_ring: switch to new memory access APIs
  virtio: add virtio 1.0 feature bit
  virtio: make endian-ness depend on virtio 1.0
  virtio_config: endian conversion for v1.0
  virtio: set FEATURES_OK
  virtio_net: fix types for in memory structures
  virtio_blk: fix types for in memory structures

Rusty Russell (3):
  virtio: use u32, not bitmap for struct virtio_device's features
  virtio: add support for 64 bit features.
  virtio_net: use v1.0 endian.

Thomas Huth (1):
  KVM: s390: Set virtio-ccw transport revision

 include/linux/virtio.h                 |   6 +-
 include/linux/virtio_byteorder.h       |  29 ++++++
 include/linux/virtio_config.h          |  33 +++++--
 include/uapi/linux/virtio_blk.h        |  15 +--
 include/uapi/linux/virtio_config.h     |   9 +-
 include/uapi/linux/virtio_net.h        |  15 +--
 include/uapi/linux/virtio_ring.h       |  49 +++++-----
 tools/virtio/linux/virtio.h            |  22 +----
 tools/virtio/linux/virtio_config.h     |   2 +-
 drivers/block/virtio_blk.c             |   4 +
 drivers/char/virtio_console.c          |   2 +-
 drivers/lguest/lguest_device.c         |  16 ++--
 drivers/net/virtio_net.c               |  31 ++++---
 drivers/remoteproc/remoteproc_virtio.c |   7 +-
 drivers/s390/kvm/kvm_virtio.c          |  10 +-
 drivers/s390/kvm/virtio_ccw.c          | 165 +++++++++++++++++++++++++++------
 drivers/virtio/virtio.c                |  47 ++++++----
 drivers/virtio/virtio_mmio.c           |  20 ++--
 drivers/virtio/virtio_pci.c            |   8 +-
 drivers/virtio/virtio_ring.c           | 109 +++++++++++++---------
 tools/virtio/virtio_test.c             |   5 +-
 tools/virtio/vringh_test.c             |  16 ++--
 include/uapi/linux/Kbuild              |   1 +
 23 files changed, 406 insertions(+), 215 deletions(-)
 create mode 100644 include/linux/virtio_byteorder.h

-- 
MST

[PATCH RFC v3 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_byteorder.h | 29 ++++++++++++++++++++++++
 include/linux/virtio_config.h    | 16 +++++++++++++
 include/uapi/linux/virtio_ring.h | 49 ++++++++++++++++++++--------------------
 include/uapi/linux/Kbuild        |  1 +
 4 files changed, 71 insertions(+), 24 deletions(-)
 create mode 100644 include/linux/virtio_byteorder.h

diff --git a/include/linux/virtio_byteorder.h b/include/linux/virtio_byteorder.h
new file mode 100644
index 0000000..7afdd8a
--- /dev/null
+++ b/include/linux/virtio_byteorder.h
@@ -0,0 +1,29 @@
+#ifndef _LINUX_VIRTIO_BYTEORDER_H
+#define _LINUX_VIRTIO_BYTEORDER_H
+#include <linux/types.h>
+#include <uapi/linux/virtio_types.h>
+
+/* Memory accessors for handling virtio in modern little endian and in
+ * compatibility big endian format. */
+
+#define __DEFINE_VIRTIO_XX_TO_CPU(bits) \
+static inline u##bits __virtio##bits##_to_cpu(bool little_endian, __virtio##bits val) \
+{ \
+	if (little_endian) \
+		return le##bits##_to_cpu((__force __le##bits)val); \
+	else \
+		return (__force u##bits)val; \
+} \
+static inline __virtio##bits __cpu_to_virtio##bits(bool little_endian, u##bits val) \
+{ \
+	if (little_endian) \
+		return (__force __virtio##bits)cpu_to_le##bits(val); \
+	else \
+		return val; \
+}
+
+__DEFINE_VIRTIO_XX_TO_CPU(16)
+__DEFINE_VIRTIO_XX_TO_CPU(32)
+__DEFINE_VIRTIO_XX_TO_CPU(64)
+
+#endif /* _LINUX_VIRTIO_BYTEORDER */
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 v3 01/16] virtio: memory access APIs

[Cornelia Huck]

On Wed, 22 Oct 2014 21:44:08 +0300
"Michael S. Tsirkin" <mst@redhat.com> 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_byteorder.h | 29 ++++++++++++++++++++++++
>  include/linux/virtio_config.h    | 16 +++++++++++++
>  include/uapi/linux/virtio_ring.h | 49 ++++++++++++++++++++--------------------
>  include/uapi/linux/Kbuild        |  1 +
>  4 files changed, 71 insertions(+), 24 deletions(-)
>  create mode 100644 include/linux/virtio_byteorder.h
> 
> diff --git a/include/linux/virtio_byteorder.h b/include/linux/virtio_byteorder.h
> new file mode 100644
> index 0000000..7afdd8a
> --- /dev/null
> +++ b/include/linux/virtio_byteorder.h
> @@ -0,0 +1,29 @@
> +#ifndef _LINUX_VIRTIO_BYTEORDER_H
> +#define _LINUX_VIRTIO_BYTEORDER_H
> +#include <linux/types.h>
> +#include <uapi/linux/virtio_types.h>
> +
> +/* Memory accessors for handling virtio in modern little endian and in
> + * compatibility big endian format. */

s/big/native/

> +
> +#define __DEFINE_VIRTIO_XX_TO_CPU(bits) \
> +static inline u##bits __virtio##bits##_to_cpu(bool little_endian, __virtio##bits val) \
> +{ \
> +	if (little_endian) \
> +		return le##bits##_to_cpu((__force __le##bits)val); \
> +	else \
> +		return (__force u##bits)val; \
> +} \
> +static inline __virtio##bits __cpu_to_virtio##bits(bool little_endian, u##bits val) \
> +{ \
> +	if (little_endian) \
> +		return (__force __virtio##bits)cpu_to_le##bits(val); \
> +	else \
> +		return val; \
> +}
> +
> +__DEFINE_VIRTIO_XX_TO_CPU(16)
> +__DEFINE_VIRTIO_XX_TO_CPU(32)
> +__DEFINE_VIRTIO_XX_TO_CPU(64)

...although I'm still not too happy with macro-generated helpers.

> +
> +#endif /* _LINUX_VIRTIO_BYTEORDER */

> 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

> @@ -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;
>  };

I think all of these __virtio types need an explanation somewhere as to
what they mean, e.g.:

/*
 * __virtio{16,32,64} have the following meaning:
 * - __u{16,32,64} for virtio devices in legacy mode,
 *   accessed in native endian
 * - __le{16,32,64} for standard-compliant virtio devices
 */

Re: [PATCH RFC v3 01/16] virtio: memory access APIs

[Michael S. Tsirkin]

On Thu, Oct 23, 2014 at 09:54:05AM +0200, Cornelia Huck wrote:
> On Wed, 22 Oct 2014 21:44:08 +0300
> "Michael S. Tsirkin" <mst@redhat.com> 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_byteorder.h | 29 ++++++++++++++++++++++++
> >  include/linux/virtio_config.h    | 16 +++++++++++++
> >  include/uapi/linux/virtio_ring.h | 49 ++++++++++++++++++++--------------------
> >  include/uapi/linux/Kbuild        |  1 +
> >  4 files changed, 71 insertions(+), 24 deletions(-)
> >  create mode 100644 include/linux/virtio_byteorder.h
> > 
> > diff --git a/include/linux/virtio_byteorder.h b/include/linux/virtio_byteorder.h
> > new file mode 100644
> > index 0000000..7afdd8a
> > --- /dev/null
> > +++ b/include/linux/virtio_byteorder.h
> > @@ -0,0 +1,29 @@
> > +#ifndef _LINUX_VIRTIO_BYTEORDER_H
> > +#define _LINUX_VIRTIO_BYTEORDER_H
> > +#include <linux/types.h>
> > +#include <uapi/linux/virtio_types.h>
> > +
> > +/* Memory accessors for handling virtio in modern little endian and in
> > + * compatibility big endian format. */
> 
> s/big/native/

Thanks.

> > +
> > +#define __DEFINE_VIRTIO_XX_TO_CPU(bits) \
> > +static inline u##bits __virtio##bits##_to_cpu(bool little_endian, __virtio##bits val) \
> > +{ \
> > +	if (little_endian) \
> > +		return le##bits##_to_cpu((__force __le##bits)val); \
> > +	else \
> > +		return (__force u##bits)val; \
> > +} \
> > +static inline __virtio##bits __cpu_to_virtio##bits(bool little_endian, u##bits val) \
> > +{ \
> > +	if (little_endian) \
> > +		return (__force __virtio##bits)cpu_to_le##bits(val); \
> > +	else \
> > +		return val; \
> > +}
> > +
> > +__DEFINE_VIRTIO_XX_TO_CPU(16)
> > +__DEFINE_VIRTIO_XX_TO_CPU(32)
> > +__DEFINE_VIRTIO_XX_TO_CPU(64)
> 
> ...although I'm still not too happy with macro-generated helpers.

I'm fine with open-coding them.

> > +
> > +#endif /* _LINUX_VIRTIO_BYTEORDER */
> 
> > 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
> 
> > @@ -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;
> >  };
> 
> I think all of these __virtio types need an explanation somewhere as to
> what they mean, e.g.:
> 
> /*
>  * __virtio{16,32,64} have the following meaning:
>  * - __u{16,32,64} for virtio devices in legacy mode,
>  *   accessed in native endian
>  * - __le{16,32,64} for standard-compliant virtio devices
>  */

Will do.

-- 
MST

[PATCH RFC v3 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 v3 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 v3 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 v3 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

Re: [PATCH RFC v3 05/16] virtio: add virtio 1.0 feature bit

[Cornelia Huck]

On Wed, 22 Oct 2014 21:44:31 +0300
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> 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(-)

Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>

[PATCH RFC v3 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

Re: [PATCH RFC v3 06/16] virtio: make endian-ness depend on virtio 1.0

[Cornelia Huck]

On Wed, 22 Oct 2014 21:44:34 +0300
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> 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(-)
> 

Looks sane.

[PATCH RFC v3 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 v3 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 v3 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

Re: [PATCH RFC v3 09/16] virtio: set FEATURES_OK

[Cornelia Huck]

On Wed, 22 Oct 2014 21:44:44 +0300
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> 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(-)
> 

>  	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;
> +		}
> +	}
> +

Ugh, I just realize that virtio-ccw has a problem with that mechanism :(

Up to now, the driver only propagated status to the device: For
virtio-ccw, this was easily implemented via a ccw that transmitted
"status" to the device. However, the "read back status" part now
actually requires that the driver can get "status" from the device, or
has a comparable way to find out that the device won't accept the
status it tried to write.

I can think of two solutions:

(1) Introduce a new ccw that actually reads the device status.
(2) Make the WRITE_STATUS ccw fail (with a unit check) if the driver
    sets FEATURES_OK after it tried to set features the device won't
    accept.

(1) is probably more generic, while (2) is more straightforward to
implement.

Good thing we actually try to finally implement this, I did not notice
this problem during the review :(

Re: [PATCH RFC v3 09/16] virtio: set FEATURES_OK

[Michael S. Tsirkin]

On Thu, Oct 23, 2014 at 02:28:08PM +0200, Cornelia Huck wrote:
> On Wed, 22 Oct 2014 21:44:44 +0300
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> 
> > 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(-)
> > 
> 
> >  	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;
> > +		}
> > +	}
> > +
> 
> Ugh, I just realize that virtio-ccw has a problem with that mechanism :(
> 
> Up to now, the driver only propagated status to the device: For
> virtio-ccw, this was easily implemented via a ccw that transmitted
> "status" to the device. However, the "read back status" part now
> actually requires that the driver can get "status" from the device, or
> has a comparable way to find out that the device won't accept the
> status it tried to write.

Ugh, it actually caches the status in the transport :(


> I can think of two solutions:
> 
> (1) Introduce a new ccw that actually reads the device status.
> (2) Make the WRITE_STATUS ccw fail (with a unit check) if the driver
>     sets FEATURES_OK after it tried to set features the device won't
>     accept.
> 
> (1) is probably more generic, while (2) is more straightforward to
> implement.
> 
> Good thing we actually try to finally implement this,

> I did not notice
> this problem during the review :(

Well, it's a nuisance, but the spec is out.
It seems to me a new command would be a substantive change so we can't
do this in errata.

Option (2) would require two statements for drivers and devices,
but since it's clearly the case for correct drivers/devices
that command does not fail, it follows that this
is not a substantive change so it can be fixed
in an errata.

So the new command would have to be optional, please open
two issues in the TC: one documenting that driver must check
WRITE_STATUS and device can fail WRITE_STATUS, and another
for adding READ_STATUS (which will have to wait until
the next CS).


-- 
MST

Re: [PATCH RFC v3 09/16] virtio: set FEATURES_OK

[Cornelia Huck]

On Thu, 23 Oct 2014 15:51:39 +0300
"Michael S. Tsirkin" <mst@redhat.com> wrote:

> On Thu, Oct 23, 2014 at 02:28:08PM +0200, Cornelia Huck wrote:
> > On Wed, 22 Oct 2014 21:44:44 +0300
> > "Michael S. Tsirkin" <mst@redhat.com> wrote:
> > 
> > > 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(-)
> > > 
> > 
> > >  	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;
> > > +		}
> > > +	}
> > > +
> > 
> > Ugh, I just realize that virtio-ccw has a problem with that mechanism :(
> > 
> > Up to now, the driver only propagated status to the device: For
> > virtio-ccw, this was easily implemented via a ccw that transmitted
> > "status" to the device. However, the "read back status" part now
> > actually requires that the driver can get "status" from the device, or
> > has a comparable way to find out that the device won't accept the
> > status it tried to write.
> 
> Ugh, it actually caches the status in the transport :(

Well, it worked as long as this was unidirectional...

> 
> 
> > I can think of two solutions:
> > 
> > (1) Introduce a new ccw that actually reads the device status.
> > (2) Make the WRITE_STATUS ccw fail (with a unit check) if the driver
> >     sets FEATURES_OK after it tried to set features the device won't
> >     accept.
> > 
> > (1) is probably more generic, while (2) is more straightforward to
> > implement.
> > 
> > Good thing we actually try to finally implement this,
> 
> > I did not notice
> > this problem during the review :(
> 
> Well, it's a nuisance, but the spec is out.
> It seems to me a new command would be a substantive change so we can't
> do this in errata.
> 
> Option (2) would require two statements for drivers and devices,
> but since it's clearly the case for correct drivers/devices
> that command does not fail, it follows that this
> is not a substantive change so it can be fixed
> in an errata.

It only adds a new failure case, so it's not really magic, agreed.

> 
> So the new command would have to be optional, 

I think a new command should be tied to a new virtio-ccw revision.

> please open
> two issues in the TC: one documenting that driver must check
> WRITE_STATUS and device can fail WRITE_STATUS, and another
> for adding READ_STATUS (which will have to wait until
> the next CS).

I think I need to contemplate that a bit more. The problem with a new
READ_STATUS is that it is, by nature, an asynchronous command (as all
ccw commands are - the Linux guest driver uses a simple wrapper that
makes it appear synchronous). This means, for example, that every
status update now involves two channel programs instead of one, and
that reading e.g. the status sysfs attribute in Linux now triggers
channel I/O, which means several exits (at least ssch, interrupt
injection, tsch; probably more depending on what the guest does)...

Re: [PATCH RFC v3 09/16] virtio: set FEATURES_OK

[Michael S. Tsirkin]

On Thu, Oct 23, 2014 at 03:30:06PM +0200, Cornelia Huck wrote:
> On Thu, 23 Oct 2014 15:51:39 +0300
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> 
> > On Thu, Oct 23, 2014 at 02:28:08PM +0200, Cornelia Huck wrote:
> > > On Wed, 22 Oct 2014 21:44:44 +0300
> > > "Michael S. Tsirkin" <mst@redhat.com> wrote:
> > > 
> > > > 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(-)
> > > > 
> > > 
> > > >  	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;
> > > > +		}
> > > > +	}
> > > > +
> > > 
> > > Ugh, I just realize that virtio-ccw has a problem with that mechanism :(
> > > 
> > > Up to now, the driver only propagated status to the device: For
> > > virtio-ccw, this was easily implemented via a ccw that transmitted
> > > "status" to the device. However, the "read back status" part now
> > > actually requires that the driver can get "status" from the device, or
> > > has a comparable way to find out that the device won't accept the
> > > status it tried to write.
> > 
> > Ugh, it actually caches the status in the transport :(
> 
> Well, it worked as long as this was unidirectional...
> 
> > 
> > 
> > > I can think of two solutions:
> > > 
> > > (1) Introduce a new ccw that actually reads the device status.
> > > (2) Make the WRITE_STATUS ccw fail (with a unit check) if the driver
> > >     sets FEATURES_OK after it tried to set features the device won't
> > >     accept.
> > > 
> > > (1) is probably more generic, while (2) is more straightforward to
> > > implement.
> > > 
> > > Good thing we actually try to finally implement this,
> > 
> > > I did not notice
> > > this problem during the review :(
> > 
> > Well, it's a nuisance, but the spec is out.
> > It seems to me a new command would be a substantive change so we can't
> > do this in errata.
> > 
> > Option (2) would require two statements for drivers and devices,
> > but since it's clearly the case for correct drivers/devices
> > that command does not fail, it follows that this
> > is not a substantive change so it can be fixed
> > in an errata.
> 
> It only adds a new failure case, so it's not really magic, agreed.
> 
> > 
> > So the new command would have to be optional, 
> 
> I think a new command should be tied to a new virtio-ccw revision.

Or a feature bit.

> > please open
> > two issues in the TC: one documenting that driver must check
> > WRITE_STATUS and device can fail WRITE_STATUS, and another
> > for adding READ_STATUS (which will have to wait until
> > the next CS).
> 
> I think I need to contemplate that a bit more. The problem with a new
> READ_STATUS is that it is, by nature, an asynchronous command (as all
> ccw commands are - the Linux guest driver uses a simple wrapper that
> makes it appear synchronous). This means, for example, that every
> status update now involves two channel programs instead of one, and
> that reading e.g. the status sysfs attribute in Linux now triggers
> channel I/O, which means several exits (at least ssch, interrupt
> injection, tsch; probably more depending on what the guest does)...

Well it seems more robust than just caching it within guest.
Anyway, let's start with issue tracker, it does not force any specific
solution.

-- 
MST

[PATCH RFC v3 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 v3 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 v3 12/16] KVM: s390: Set virtio-ccw transport revision

[Michael S. Tsirkin]

From: Thomas Huth <thuth@linux.vnet.ibm.com>

With the new SET-VIRTIO-REVISION command of the virtio 1.0 standard, we
can now negotiate the virtio-ccw revision after setting a channel online.

Note that we don't negotiate version 1 yet.

[Cornelia Huck: reworked revision loop a bit]
Reviewed-by: David Hildenbrand <dahi@linux.vnet.ibm.com>
Signed-off-by: Thomas Huth <thuth@linux.vnet.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/s390/kvm/virtio_ccw.c | 63 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 63 insertions(+)

diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index 27aab69..394ddb8 100644
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -55,6 +55,7 @@ struct virtio_ccw_device {
 	struct ccw_device *cdev;
 	__u32 curr_io;
 	int err;
+	unsigned int revision; /* Transport revision */
 	wait_queue_head_t wait_q;
 	spinlock_t lock;
 	struct list_head virtqueues;
@@ -86,6 +87,15 @@ struct virtio_thinint_area {
 	u8 isc;
 } __packed;
 
+struct virtio_rev_info {
+	__u16 revision;
+	__u16 length;
+	__u8 data[];
+};
+
+/* the highest virtio-ccw revision we support */
+#define VIRTIO_CCW_REV_MAX 0
+
 struct virtio_ccw_vq_info {
 	struct virtqueue *vq;
 	int num;
@@ -122,6 +132,7 @@ static struct airq_info *airq_areas[MAX_AIRQ_AREAS];
 #define CCW_CMD_WRITE_STATUS 0x31
 #define CCW_CMD_READ_VQ_CONF 0x32
 #define CCW_CMD_SET_IND_ADAPTER 0x73
+#define CCW_CMD_SET_VIRTIO_REV 0x83
 
 #define VIRTIO_CCW_DOING_SET_VQ 0x00010000
 #define VIRTIO_CCW_DOING_RESET 0x00040000
@@ -134,6 +145,7 @@ static struct airq_info *airq_areas[MAX_AIRQ_AREAS];
 #define VIRTIO_CCW_DOING_READ_VQ_CONF 0x02000000
 #define VIRTIO_CCW_DOING_SET_CONF_IND 0x04000000
 #define VIRTIO_CCW_DOING_SET_IND_ADAPTER 0x08000000
+#define VIRTIO_CCW_DOING_SET_VIRTIO_REV 0x10000000
 #define VIRTIO_CCW_INTPARM_MASK 0xffff0000
 
 static struct virtio_ccw_device *to_vc_device(struct virtio_device *vdev)
@@ -934,6 +946,7 @@ static void virtio_ccw_int_handler(struct ccw_device *cdev,
 		case VIRTIO_CCW_DOING_RESET:
 		case VIRTIO_CCW_DOING_READ_VQ_CONF:
 		case VIRTIO_CCW_DOING_SET_IND_ADAPTER:
+		case VIRTIO_CCW_DOING_SET_VIRTIO_REV:
 			vcdev->curr_io &= ~activity;
 			wake_up(&vcdev->wait_q);
 			break;
@@ -1049,6 +1062,51 @@ static int virtio_ccw_offline(struct ccw_device *cdev)
 	return 0;
 }
 
+static int virtio_ccw_set_transport_rev(struct virtio_ccw_device *vcdev)
+{
+	struct virtio_rev_info *rev;
+	struct ccw1 *ccw;
+	int ret;
+
+	ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);
+	if (!ccw)
+		return -ENOMEM;
+	rev = kzalloc(sizeof(*rev), GFP_DMA | GFP_KERNEL);
+	if (!rev) {
+		kfree(ccw);
+		return -ENOMEM;
+	}
+
+	/* Set transport revision */
+	ccw->cmd_code = CCW_CMD_SET_VIRTIO_REV;
+	ccw->flags = 0;
+	ccw->count = sizeof(*rev);
+	ccw->cda = (__u32)(unsigned long)rev;
+
+	vcdev->revision = VIRTIO_CCW_REV_MAX;
+	do {
+		rev->revision = vcdev->revision;
+		/* none of our supported revisions carry payload */
+		rev->length = 0;
+		ret = ccw_io_helper(vcdev, ccw,
+				    VIRTIO_CCW_DOING_SET_VIRTIO_REV);
+		if (ret == -EOPNOTSUPP) {
+			if (vcdev->revision == 0)
+				/*
+				 * The host device does not support setting
+				 * the revision: let's operate it in legacy
+				 * mode.
+				 */
+				ret = 0;
+			else
+				vcdev->revision--;
+		}
+	} while (ret == -EOPNOTSUPP);
+
+	kfree(ccw);
+	kfree(rev);
+	return ret;
+}
 
 static int virtio_ccw_online(struct ccw_device *cdev)
 {
@@ -1089,6 +1147,11 @@ static int virtio_ccw_online(struct ccw_device *cdev)
 	spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
 	vcdev->vdev.id.vendor = cdev->id.cu_type;
 	vcdev->vdev.id.device = cdev->id.cu_model;
+
+	ret = virtio_ccw_set_transport_rev(vcdev);
+	if (ret)
+		goto out_free;
+
 	ret = register_virtio_device(&vcdev->vdev);
 	if (ret) {
 		dev_warn(&cdev->dev, "Failed to register virtio device: %d\n",
-- 
MST

[PATCH RFC v3 13/16] KVM: s390: virtio-ccw revision 1 SET_VQ

[Michael S. Tsirkin]

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

The CCW_CMD_SET_VQ command has a different format for revision 1+
devices, allowing to specify a more complex virtqueue layout. For
now, we stay however with the old layout and simply use the new
command format for virtio-1 devices.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 drivers/s390/kvm/virtio_ccw.c | 54 +++++++++++++++++++++++++++++++++----------
 1 file changed, 42 insertions(+), 12 deletions(-)

diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index 394ddb8..a994078 100644
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -68,13 +68,22 @@ struct virtio_ccw_device {
 	void *airq_info;
 };
 
-struct vq_info_block {
+struct vq_info_block_legacy {
 	__u64 queue;
 	__u32 align;
 	__u16 index;
 	__u16 num;
 } __packed;
 
+struct vq_info_block {
+	__u64 desc;
+	__u32 res0;
+	__u16 index;
+	__u16 num;
+	__u64 avail;
+	__u64 used;
+} __packed;
+
 struct virtio_feature_desc {
 	__u32 features;
 	__u8 index;
@@ -100,7 +109,10 @@ struct virtio_ccw_vq_info {
 	struct virtqueue *vq;
 	int num;
 	void *queue;
-	struct vq_info_block *info_block;
+	union {
+		struct vq_info_block s;
+		struct vq_info_block_legacy l;
+	} *info_block;
 	int bit_nr;
 	struct list_head node;
 	long cookie;
@@ -411,13 +423,22 @@ static void virtio_ccw_del_vq(struct virtqueue *vq, struct ccw1 *ccw)
 	spin_unlock_irqrestore(&vcdev->lock, flags);
 
 	/* Release from host. */
-	info->info_block->queue = 0;
-	info->info_block->align = 0;
-	info->info_block->index = index;
-	info->info_block->num = 0;
+	if (vcdev->revision == 0) {
+		info->info_block->l.queue = 0;
+		info->info_block->l.align = 0;
+		info->info_block->l.index = index;
+		info->info_block->l.num = 0;
+		ccw->count = sizeof(info->info_block->l);
+	} else {
+		info->info_block->s.desc = 0;
+		info->info_block->s.index = index;
+		info->info_block->s.num = 0;
+		info->info_block->s.avail = 0;
+		info->info_block->s.used = 0;
+		ccw->count = sizeof(info->info_block->s);
+	}
 	ccw->cmd_code = CCW_CMD_SET_VQ;
 	ccw->flags = 0;
-	ccw->count = sizeof(*info->info_block);
 	ccw->cda = (__u32)(unsigned long)(info->info_block);
 	ret = ccw_io_helper(vcdev, ccw,
 			    VIRTIO_CCW_DOING_SET_VQ | index);
@@ -500,13 +521,22 @@ static struct virtqueue *virtio_ccw_setup_vq(struct virtio_device *vdev,
 	}
 
 	/* Register it with the host. */
-	info->info_block->queue = (__u64)info->queue;
-	info->info_block->align = KVM_VIRTIO_CCW_RING_ALIGN;
-	info->info_block->index = i;
-	info->info_block->num = info->num;
+	if (vcdev->revision == 0) {
+		info->info_block->l.queue = (__u64)info->queue;
+		info->info_block->l.align = KVM_VIRTIO_CCW_RING_ALIGN;
+		info->info_block->l.index = i;
+		info->info_block->l.num = info->num;
+		ccw->count = sizeof(info->info_block->l);
+	} else {
+		info->info_block->s.desc = (__u64)info->queue;
+		info->info_block->s.index = i;
+		info->info_block->s.num = info->num;
+		info->info_block->s.avail = (__u64)virtqueue_get_avail(vq);
+		info->info_block->s.used = (__u64)virtqueue_get_used(vq);
+		ccw->count = sizeof(info->info_block->s);
+	}
 	ccw->cmd_code = CCW_CMD_SET_VQ;
 	ccw->flags = 0;
-	ccw->count = sizeof(*info->info_block);
 	ccw->cda = (__u32)(unsigned long)(info->info_block);
 	err = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_SET_VQ | i);
 	if (err) {
-- 
MST

[PATCH RFC v3 14/16] KVM: s390: enable virtio-ccw revision 1

[Michael S. Tsirkin]

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

Now that virtio-ccw has everything needed to support virtio 1.0 in
place, try to enable it if the host supports it.

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/s390/kvm/virtio_ccw.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index a994078..c42eda3 100644
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -103,7 +103,7 @@ struct virtio_rev_info {
 };
 
 /* the highest virtio-ccw revision we support */
-#define VIRTIO_CCW_REV_MAX 0
+#define VIRTIO_CCW_REV_MAX 1
 
 struct virtio_ccw_vq_info {
 	struct virtqueue *vq;
-- 
MST

[PATCH RFC v3 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 v3 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

Re: [PATCH RFC v3 00/16] linux: towards virtio-1 guest support

[Michael S. Tsirkin]

On Wed, Oct 22, 2014 at 09:44:05PM +0300, Michael S. Tsirkin wrote:
> Based on patches by Cornelia and others, but
> with an API that should allow better static checking of code,
> and slightly more concervative changes in vring.

Note: sparse found some issues, so please wait a bit with testing,
I'll send v4 shortly.

> Changes from v2:
> 	add missing virtio_byteorder.h
> 
> Cornelia Huck (4):
>   virtio: allow transports to get avail/used addresses
>   virtio_blk: use virtio v1.0 endian
>   KVM: s390: virtio-ccw revision 1 SET_VQ
>   KVM: s390: enable virtio-ccw revision 1
> 
> Michael S. Tsirkin (8):
>   virtio: memory access APIs
>   virtio_ring: switch to new memory access APIs
>   virtio: add virtio 1.0 feature bit
>   virtio: make endian-ness depend on virtio 1.0
>   virtio_config: endian conversion for v1.0
>   virtio: set FEATURES_OK
>   virtio_net: fix types for in memory structures
>   virtio_blk: fix types for in memory structures
> 
> Rusty Russell (3):
>   virtio: use u32, not bitmap for struct virtio_device's features
>   virtio: add support for 64 bit features.
>   virtio_net: use v1.0 endian.
> 
> Thomas Huth (1):
>   KVM: s390: Set virtio-ccw transport revision
> 
>  include/linux/virtio.h                 |   6 +-
>  include/linux/virtio_byteorder.h       |  29 ++++++
>  include/linux/virtio_config.h          |  33 +++++--
>  include/uapi/linux/virtio_blk.h        |  15 +--
>  include/uapi/linux/virtio_config.h     |   9 +-
>  include/uapi/linux/virtio_net.h        |  15 +--
>  include/uapi/linux/virtio_ring.h       |  49 +++++-----
>  tools/virtio/linux/virtio.h            |  22 +----
>  tools/virtio/linux/virtio_config.h     |   2 +-
>  drivers/block/virtio_blk.c             |   4 +
>  drivers/char/virtio_console.c          |   2 +-
>  drivers/lguest/lguest_device.c         |  16 ++--
>  drivers/net/virtio_net.c               |  31 ++++---
>  drivers/remoteproc/remoteproc_virtio.c |   7 +-
>  drivers/s390/kvm/kvm_virtio.c          |  10 +-
>  drivers/s390/kvm/virtio_ccw.c          | 165 +++++++++++++++++++++++++++------
>  drivers/virtio/virtio.c                |  47 ++++++----
>  drivers/virtio/virtio_mmio.c           |  20 ++--
>  drivers/virtio/virtio_pci.c            |   8 +-
>  drivers/virtio/virtio_ring.c           | 109 +++++++++++++---------
>  tools/virtio/virtio_test.c             |   5 +-
>  tools/virtio/vringh_test.c             |  16 ++--
>  include/uapi/linux/Kbuild              |   1 +
>  23 files changed, 406 insertions(+), 215 deletions(-)
>  create mode 100644 include/linux/virtio_byteorder.h
> 
> -- 
> MST
>