subject:"\[PATCH\] vhost\: move is_le setup to the backend"

Re: [PATCH] vhost: move is_le setup to the backend

2016-01-12 Thread Michael S. Tsirkin

On Mon, Jan 11, 2016 at 03:39:38PM +0100, Greg Kurz wrote:
> The vq->is_le field is used to fix endianness when accessing the vring via
> the cpu_to_vhost16() and vhost16_to_cpu() helpers in the following cases:
> 
> 1) host is big endian and device is modern virtio
> 
> 2) host has cross-endian support and device is legacy virtio with a different
>endianness than the host
> 
> Both cases rely on the VHOST_SET_FEATURES ioctl, but 2) also needs the
> VHOST_SET_VRING_ENDIAN ioctl to be called by userspace. Since vq->is_le
> is only needed when the backend is active, it was decided to set it at
> backend start.
> 
> This is currently done in vhost_init_used()->vhost_init_is_le() but it
> obfuscates the core vhost code. This patch moves the is_le setup to a
> dedicated function that is called from the backend code.
> 
> Note vhost_net is the only backend that can pass vq->private_data == NULL to
> vhost_init_used(), hence the "if (sock)" branch.
> 
> No behaviour change.
> 
> Reviewed-by: Cornelia Huck 
> Signed-off-by: Greg Kurz 
> ---
> 
> Hi Michael,
> 
> This is a cleanup patch I had posted last year:
> 
> http://patchwork.ozlabs.org/patch/538277/
> 
> I am just reposting with Cornelia's R-b.
> 
> Cheers.
> 
> --
> Greg
> 
>  drivers/vhost/net.c   |6 ++
>  drivers/vhost/scsi.c  |3 +++
>  drivers/vhost/test.c  |2 ++
>  drivers/vhost/vhost.c |   12 +++-
>  drivers/vhost/vhost.h |1 +
>  5 files changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 9eda69e40678..d6319cb2664c 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -917,6 +917,12 @@ static long vhost_net_set_backend(struct vhost_net *n, 
> unsigned index, int fd)
>  
>   vhost_net_disable_vq(n, vq);
>   vq->private_data = sock;
> +
> + if (sock)
> + vhost_set_is_le(vq);
> + else
> + vq->is_le = virtio_legacy_is_little_endian();
> +
>   r = vhost_init_used(vq);
>   if (r)
>   goto err_used;

This part is kind of ugly. I think it's cleaner is the generic code.
How about we teach vhost_set_is_le to test vq->private_data and DTRT?

> diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
> index 29cfc57d496e..1f4f405ebba8 100644
> --- a/drivers/vhost/scsi.c
> +++ b/drivers/vhost/scsi.c
> @@ -1274,6 +1274,9 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
>   vq = >vqs[i].vq;
>   mutex_lock(>mutex);
>   vq->private_data = vs_tpg;
> +
> + vhost_set_is_le(vq);
> +
>   vhost_init_used(vq);
>   mutex_unlock(>mutex);
>   }
> diff --git a/drivers/vhost/test.c b/drivers/vhost/test.c
> index f2882ac98726..b1c7df502211 100644
> --- a/drivers/vhost/test.c
> +++ b/drivers/vhost/test.c
> @@ -196,6 +196,8 @@ static long vhost_test_run(struct vhost_test *n, int test)
>   oldpriv = vq->private_data;
>   vq->private_data = priv;
>  
> + vhost_set_is_le(vq);
> +
>   r = vhost_init_used(>vqs[index]);
>  
>   mutex_unlock(>mutex);
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index ad2146a9ab2d..e688eb801d43 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -113,6 +113,12 @@ static void vhost_init_is_le(struct vhost_virtqueue *vq)
>  }
>  #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
>  
> +void vhost_set_is_le(struct vhost_virtqueue *vq)
> +{
> + vhost_init_is_le(vq);
> +}
> +EXPORT_SYMBOL_GPL(vhost_set_is_le);
> +
>  static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
>   poll_table *pt)
>  {

Why do we need this wrapper? Why not just export vhost_init_is_le?
Or rename vhost_init_is_le->vhost_set_is_le if you prefer.

> @@ -1156,12 +1162,8 @@ int vhost_init_used(struct vhost_virtqueue *vq)
>  {
>   __virtio16 last_used_idx;
>   int r;
> - if (!vq->private_data) {
> - vq->is_le = virtio_legacy_is_little_endian();
> + if (!vq->private_data)
>   return 0;
> - }
> -
> - vhost_init_is_le(vq);
>  
>   r = vhost_update_used_flags(vq);
>   if (r)
> diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
> index d3f767448a72..af5d33797937 100644
> --- a/drivers/vhost/vhost.h
> +++ b/drivers/vhost/vhost.h
> @@ -162,6 +162,7 @@ bool vhost_enable_notify(struct vhost_dev *, struct 
> vhost_virtqueue *);
>  
>  int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
>   unsigned int log_num, u64 len);
> +void vhost_set_is_le(struct vhost_virtqueue *vq);
>  
>  #define vq_err(vq, fmt, ...) do {  \
>   pr_debug(pr_fmt(fmt), ##__VA_ARGS__);   \
___

Re: [PATCH] vhost: move is_le setup to the backend

2016-01-12 Thread Michael S. Tsirkin

On Tue, Jan 12, 2016 at 11:31:00AM +0100, Greg Kurz wrote:
> On Tue, 12 Jan 2016 12:01:32 +0200
> "Michael S. Tsirkin"  wrote:
> 
> > On Mon, Jan 11, 2016 at 03:39:38PM +0100, Greg Kurz wrote:
> > > The vq->is_le field is used to fix endianness when accessing the vring via
> > > the cpu_to_vhost16() and vhost16_to_cpu() helpers in the following cases:
> > > 
> > > 1) host is big endian and device is modern virtio
> > > 
> > > 2) host has cross-endian support and device is legacy virtio with a 
> > > different
> > >endianness than the host
> > > 
> > > Both cases rely on the VHOST_SET_FEATURES ioctl, but 2) also needs the
> > > VHOST_SET_VRING_ENDIAN ioctl to be called by userspace. Since vq->is_le
> > > is only needed when the backend is active, it was decided to set it at
> > > backend start.
> > > 
> > > This is currently done in vhost_init_used()->vhost_init_is_le() but it
> > > obfuscates the core vhost code. This patch moves the is_le setup to a
> > > dedicated function that is called from the backend code.
> > > 
> > > Note vhost_net is the only backend that can pass vq->private_data == NULL 
> > > to
> > > vhost_init_used(), hence the "if (sock)" branch.
> > > 
> > > No behaviour change.
> > > 
> > > Reviewed-by: Cornelia Huck 
> > > Signed-off-by: Greg Kurz 
> > > ---
> > > 
> > > Hi Michael,
> > > 
> > > This is a cleanup patch I had posted last year:
> > > 
> > > http://patchwork.ozlabs.org/patch/538277/
> > > 
> > > I am just reposting with Cornelia's R-b.
> > > 
> > > Cheers.
> > > 
> > > --
> > > Greg
> > > 
> > >  drivers/vhost/net.c   |6 ++
> > >  drivers/vhost/scsi.c  |3 +++
> > >  drivers/vhost/test.c  |2 ++
> > >  drivers/vhost/vhost.c |   12 +++-
> > >  drivers/vhost/vhost.h |1 +
> > >  5 files changed, 19 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> > > index 9eda69e40678..d6319cb2664c 100644
> > > --- a/drivers/vhost/net.c
> > > +++ b/drivers/vhost/net.c
> > > @@ -917,6 +917,12 @@ static long vhost_net_set_backend(struct vhost_net 
> > > *n, unsigned index, int fd)
> > >  
> > >   vhost_net_disable_vq(n, vq);
> > >   vq->private_data = sock;
> > > +
> > > + if (sock)
> > > + vhost_set_is_le(vq);
> > > + else
> > > + vq->is_le = virtio_legacy_is_little_endian();
> > > +
> > >   r = vhost_init_used(vq);
> > >   if (r)
> > >   goto err_used;  
> > 
> > This part is kind of ugly. I think it's cleaner is the generic code.
> > How about we teach vhost_set_is_le to test vq->private_data and DTRT?
> > 
> 
> You're right. I'll try that.
> 
> > > diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
> > > index 29cfc57d496e..1f4f405ebba8 100644
> > > --- a/drivers/vhost/scsi.c
> > > +++ b/drivers/vhost/scsi.c
> > > @@ -1274,6 +1274,9 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
> > >   vq = >vqs[i].vq;
> > >   mutex_lock(>mutex);
> > >   vq->private_data = vs_tpg;
> > > +
> > > + vhost_set_is_le(vq);
> > > +
> > >   vhost_init_used(vq);
> > >   mutex_unlock(>mutex);
> > >   }
> > > diff --git a/drivers/vhost/test.c b/drivers/vhost/test.c
> > > index f2882ac98726..b1c7df502211 100644
> > > --- a/drivers/vhost/test.c
> > > +++ b/drivers/vhost/test.c
> > > @@ -196,6 +196,8 @@ static long vhost_test_run(struct vhost_test *n, int 
> > > test)
> > >   oldpriv = vq->private_data;
> > >   vq->private_data = priv;
> > >  
> > > + vhost_set_is_le(vq);
> > > +
> > >   r = vhost_init_used(>vqs[index]);
> > >  
> > >   mutex_unlock(>mutex);
> > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> > > index ad2146a9ab2d..e688eb801d43 100644
> > > --- a/drivers/vhost/vhost.c
> > > +++ b/drivers/vhost/vhost.c
> > > @@ -113,6 +113,12 @@ static void vhost_init_is_le(struct vhost_virtqueue 
> > > *vq)
> > >  }
> > >  #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
> > >  
> > > +void vhost_set_is_le(struct vhost_virtqueue *vq)
> > > +{
> > > + vhost_init_is_le(vq);
> > > +}
> > > +EXPORT_SYMBOL_GPL(vhost_set_is_le);
> > > +
> > >  static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
> > >   poll_table *pt)
> > >  {  
> > 
> > Why do we need this wrapper? Why not just export vhost_init_is_le?
> 
> This is a tentative workaround to:
> 
> WARNING: EXPORT_SYMBOL(foo); should immediately follow its function/variable
> #35: FILE: drivers/vhost/vhost.c:116:
> +EXPORT_SYMBOL_GPL(vhost_init_is_le);
> 
> Other possibility is to put the EXPORT_SYMBOL_GPL statement in both
> conditional compilation blocks. Maybe better ?

That, or ignore the warning.

> > Or rename vhost_init_is_le->vhost_set_is_le if you prefer.
> > 
> > > @@ -1156,12 +1162,8 @@ int vhost_init_used(struct

Re: [PATCH] vhost: move is_le setup to the backend

2016-01-12 Thread Greg Kurz

On Tue, 12 Jan 2016 12:01:32 +0200
"Michael S. Tsirkin"  wrote:

> On Mon, Jan 11, 2016 at 03:39:38PM +0100, Greg Kurz wrote:
> > The vq->is_le field is used to fix endianness when accessing the vring via
> > the cpu_to_vhost16() and vhost16_to_cpu() helpers in the following cases:
> > 
> > 1) host is big endian and device is modern virtio
> > 
> > 2) host has cross-endian support and device is legacy virtio with a 
> > different
> >endianness than the host
> > 
> > Both cases rely on the VHOST_SET_FEATURES ioctl, but 2) also needs the
> > VHOST_SET_VRING_ENDIAN ioctl to be called by userspace. Since vq->is_le
> > is only needed when the backend is active, it was decided to set it at
> > backend start.
> > 
> > This is currently done in vhost_init_used()->vhost_init_is_le() but it
> > obfuscates the core vhost code. This patch moves the is_le setup to a
> > dedicated function that is called from the backend code.
> > 
> > Note vhost_net is the only backend that can pass vq->private_data == NULL to
> > vhost_init_used(), hence the "if (sock)" branch.
> > 
> > No behaviour change.
> > 
> > Reviewed-by: Cornelia Huck 
> > Signed-off-by: Greg Kurz 
> > ---
> > 
> > Hi Michael,
> > 
> > This is a cleanup patch I had posted last year:
> > 
> > http://patchwork.ozlabs.org/patch/538277/
> > 
> > I am just reposting with Cornelia's R-b.
> > 
> > Cheers.
> > 
> > --
> > Greg
> > 
> >  drivers/vhost/net.c   |6 ++
> >  drivers/vhost/scsi.c  |3 +++
> >  drivers/vhost/test.c  |2 ++
> >  drivers/vhost/vhost.c |   12 +++-
> >  drivers/vhost/vhost.h |1 +
> >  5 files changed, 19 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> > index 9eda69e40678..d6319cb2664c 100644
> > --- a/drivers/vhost/net.c
> > +++ b/drivers/vhost/net.c
> > @@ -917,6 +917,12 @@ static long vhost_net_set_backend(struct vhost_net *n, 
> > unsigned index, int fd)
> >  
> > vhost_net_disable_vq(n, vq);
> > vq->private_data = sock;
> > +
> > +   if (sock)
> > +   vhost_set_is_le(vq);
> > +   else
> > +   vq->is_le = virtio_legacy_is_little_endian();
> > +
> > r = vhost_init_used(vq);
> > if (r)
> > goto err_used;  
> 
> This part is kind of ugly. I think it's cleaner is the generic code.
> How about we teach vhost_set_is_le to test vq->private_data and DTRT?
> 

You're right. I'll try that.

> > diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
> > index 29cfc57d496e..1f4f405ebba8 100644
> > --- a/drivers/vhost/scsi.c
> > +++ b/drivers/vhost/scsi.c
> > @@ -1274,6 +1274,9 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
> > vq = >vqs[i].vq;
> > mutex_lock(>mutex);
> > vq->private_data = vs_tpg;
> > +
> > +   vhost_set_is_le(vq);
> > +
> > vhost_init_used(vq);
> > mutex_unlock(>mutex);
> > }
> > diff --git a/drivers/vhost/test.c b/drivers/vhost/test.c
> > index f2882ac98726..b1c7df502211 100644
> > --- a/drivers/vhost/test.c
> > +++ b/drivers/vhost/test.c
> > @@ -196,6 +196,8 @@ static long vhost_test_run(struct vhost_test *n, int 
> > test)
> > oldpriv = vq->private_data;
> > vq->private_data = priv;
> >  
> > +   vhost_set_is_le(vq);
> > +
> > r = vhost_init_used(>vqs[index]);
> >  
> > mutex_unlock(>mutex);
> > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> > index ad2146a9ab2d..e688eb801d43 100644
> > --- a/drivers/vhost/vhost.c
> > +++ b/drivers/vhost/vhost.c
> > @@ -113,6 +113,12 @@ static void vhost_init_is_le(struct vhost_virtqueue 
> > *vq)
> >  }
> >  #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
> >  
> > +void vhost_set_is_le(struct vhost_virtqueue *vq)
> > +{
> > +   vhost_init_is_le(vq);
> > +}
> > +EXPORT_SYMBOL_GPL(vhost_set_is_le);
> > +
> >  static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
> > poll_table *pt)
> >  {  
> 
> Why do we need this wrapper? Why not just export vhost_init_is_le?

This is a tentative workaround to:

WARNING: EXPORT_SYMBOL(foo); should immediately follow its function/variable
#35: FILE: drivers/vhost/vhost.c:116:
+EXPORT_SYMBOL_GPL(vhost_init_is_le);

Other possibility is to put the EXPORT_SYMBOL_GPL statement in both
conditional compilation blocks. Maybe better ?

> Or rename vhost_init_is_le->vhost_set_is_le if you prefer.
> 
> > @@ -1156,12 +1162,8 @@ int vhost_init_used(struct vhost_virtqueue *vq)
> >  {
> > __virtio16 last_used_idx;
> > int r;
> > -   if (!vq->private_data) {
> > -   vq->is_le = virtio_legacy_is_little_endian();
> > +   if (!vq->private_data)
> > return 0;
> > -   }
> > -
> > -   vhost_init_is_le(vq);
> >  
> > r = vhost_update_used_flags(vq);
> > if

[PATCH] vhost: move is_le setup to the backend

2016-01-11 Thread Greg Kurz

The vq->is_le field is used to fix endianness when accessing the vring via
the cpu_to_vhost16() and vhost16_to_cpu() helpers in the following cases:

1) host is big endian and device is modern virtio

2) host has cross-endian support and device is legacy virtio with a different
   endianness than the host

Both cases rely on the VHOST_SET_FEATURES ioctl, but 2) also needs the
VHOST_SET_VRING_ENDIAN ioctl to be called by userspace. Since vq->is_le
is only needed when the backend is active, it was decided to set it at
backend start.

This is currently done in vhost_init_used()->vhost_init_is_le() but it
obfuscates the core vhost code. This patch moves the is_le setup to a
dedicated function that is called from the backend code.

Note vhost_net is the only backend that can pass vq->private_data == NULL to
vhost_init_used(), hence the "if (sock)" branch.

No behaviour change.

Reviewed-by: Cornelia Huck 
Signed-off-by: Greg Kurz 
---

Hi Michael,

This is a cleanup patch I had posted last year:

http://patchwork.ozlabs.org/patch/538277/

I am just reposting with Cornelia's R-b.

Cheers.

--
Greg

 drivers/vhost/net.c   |6 ++
 drivers/vhost/scsi.c  |3 +++
 drivers/vhost/test.c  |2 ++
 drivers/vhost/vhost.c |   12 +++-
 drivers/vhost/vhost.h |1 +
 5 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 9eda69e40678..d6319cb2664c 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -917,6 +917,12 @@ static long vhost_net_set_backend(struct vhost_net *n, 
unsigned index, int fd)
 
vhost_net_disable_vq(n, vq);
vq->private_data = sock;
+
+   if (sock)
+   vhost_set_is_le(vq);
+   else
+   vq->is_le = virtio_legacy_is_little_endian();
+
r = vhost_init_used(vq);
if (r)
goto err_used;
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index 29cfc57d496e..1f4f405ebba8 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -1274,6 +1274,9 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
vq = >vqs[i].vq;
mutex_lock(>mutex);
vq->private_data = vs_tpg;
+
+   vhost_set_is_le(vq);
+
vhost_init_used(vq);
mutex_unlock(>mutex);
}
diff --git a/drivers/vhost/test.c b/drivers/vhost/test.c
index f2882ac98726..b1c7df502211 100644
--- a/drivers/vhost/test.c
+++ b/drivers/vhost/test.c
@@ -196,6 +196,8 @@ static long vhost_test_run(struct vhost_test *n, int test)
oldpriv = vq->private_data;
vq->private_data = priv;
 
+   vhost_set_is_le(vq);
+
r = vhost_init_used(>vqs[index]);
 
mutex_unlock(>mutex);
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index ad2146a9ab2d..e688eb801d43 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -113,6 +113,12 @@ static void vhost_init_is_le(struct vhost_virtqueue *vq)
 }
 #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
 
+void vhost_set_is_le(struct vhost_virtqueue *vq)
+{
+   vhost_init_is_le(vq);
+}
+EXPORT_SYMBOL_GPL(vhost_set_is_le);
+
 static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
poll_table *pt)
 {
@@ -1156,12 +1162,8 @@ int vhost_init_used(struct vhost_virtqueue *vq)
 {
__virtio16 last_used_idx;
int r;
-   if (!vq->private_data) {
-   vq->is_le = virtio_legacy_is_little_endian();
+   if (!vq->private_data)
return 0;
-   }
-
-   vhost_init_is_le(vq);
 
r = vhost_update_used_flags(vq);
if (r)
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index d3f767448a72..af5d33797937 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -162,6 +162,7 @@ bool vhost_enable_notify(struct vhost_dev *, struct 
vhost_virtqueue *);
 
 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
unsigned int log_num, u64 len);
+void vhost_set_is_le(struct vhost_virtqueue *vq);
 
 #define vq_err(vq, fmt, ...) do {  \
pr_debug(pr_fmt(fmt), ##__VA_ARGS__);   \

___
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization

Re: [PATCH] vhost: move is_le setup to the backend

2015-12-16 Thread Greg Kurz

On Thu, 12 Nov 2015 15:28:19 +0100
Greg Kurz  wrote:

> On Thu, 12 Nov 2015 15:46:30 +0200
> "Michael S. Tsirkin"  wrote:
> 
> > On Fri, Oct 30, 2015 at 12:42:35PM +0100, Greg Kurz wrote:
> > > The vq->is_le field is used to fix endianness when accessing the vring via
> > > the cpu_to_vhost16() and vhost16_to_cpu() helpers in the following cases:
> > > 
> > > 1) host is big endian and device is modern virtio
> > > 
> > > 2) host has cross-endian support and device is legacy virtio with a 
> > > different
> > >endianness than the host
> > > 
> > > Both cases rely on the VHOST_SET_FEATURES ioctl, but 2) also needs the
> > > VHOST_SET_VRING_ENDIAN ioctl to be called by userspace. Since vq->is_le
> > > is only needed when the backend is active, it was decided to set it at
> > > backend start.
> > > 
> > > This is currently done in vhost_init_used()->vhost_init_is_le() but it
> > > obfuscates the core vhost code. This patch moves the is_le setup to a
> > > dedicated function that is called from the backend code.
> > > 
> > > Note vhost_net is the only backend that can pass vq->private_data == NULL 
> > > to
> > > vhost_init_used(), hence the "if (sock)" branch.
> > > 
> > > No behaviour change.
> > > 
> > > Signed-off-by: Greg Kurz 
> > 
> > I plan to look at this next week, busy with QEMU 2.5 now.
> > 
> 
> I don't have any deadline for this since this is only a cleanup tentative.
> 
> Thanks.
> 

... but ping anyway since it was a month ago :)

Cheers.

--
Greg

> > > ---
> > >  drivers/vhost/net.c   |6 ++
> > >  drivers/vhost/scsi.c  |3 +++
> > >  drivers/vhost/test.c  |2 ++
> > >  drivers/vhost/vhost.c |   12 +++-
> > >  drivers/vhost/vhost.h |1 +
> > >  5 files changed, 19 insertions(+), 5 deletions(-)
> > > 
> > > diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> > > index 9eda69e40678..d6319cb2664c 100644
> > > --- a/drivers/vhost/net.c
> > > +++ b/drivers/vhost/net.c
> > > @@ -917,6 +917,12 @@ static long vhost_net_set_backend(struct vhost_net 
> > > *n, unsigned index, int fd)
> > >  
> > >   vhost_net_disable_vq(n, vq);
> > >   vq->private_data = sock;
> > > +
> > > + if (sock)
> > > + vhost_set_is_le(vq);
> > > + else
> > > + vq->is_le = virtio_legacy_is_little_endian();
> > > +
> > >   r = vhost_init_used(vq);
> > >   if (r)
> > >   goto err_used;
> > > diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
> > > index e25a23692822..e2644a301fa5 100644
> > > --- a/drivers/vhost/scsi.c
> > > +++ b/drivers/vhost/scsi.c
> > > @@ -1276,6 +1276,9 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
> > >   vq = >vqs[i].vq;
> > >   mutex_lock(>mutex);
> > >   vq->private_data = vs_tpg;
> > > +
> > > + vhost_set_is_le(vq);
> > > +
> > >   vhost_init_used(vq);
> > >   mutex_unlock(>mutex);
> > >   }
> > > diff --git a/drivers/vhost/test.c b/drivers/vhost/test.c
> > > index f2882ac98726..b1c7df502211 100644
> > > --- a/drivers/vhost/test.c
> > > +++ b/drivers/vhost/test.c
> > > @@ -196,6 +196,8 @@ static long vhost_test_run(struct vhost_test *n, int 
> > > test)
> > >   oldpriv = vq->private_data;
> > >   vq->private_data = priv;
> > >  
> > > + vhost_set_is_le(vq);
> > > +
> > >   r = vhost_init_used(>vqs[index]);
> > >  
> > >   mutex_unlock(>mutex);
> > > diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> > > index eec2f11809ff..6be863dcbd13 100644
> > > --- a/drivers/vhost/vhost.c
> > > +++ b/drivers/vhost/vhost.c
> > > @@ -113,6 +113,12 @@ static void vhost_init_is_le(struct vhost_virtqueue 
> > > *vq)
> > >  }
> > >  #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
> > >  
> > > +void vhost_set_is_le(struct vhost_virtqueue *vq)
> > > +{
> > > + vhost_init_is_le(vq);
> > > +}
> > > +EXPORT_SYMBOL_GPL(vhost_set_is_le);
> > > +
> > >  static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
> > >   poll_table *pt)
> > >  {
> > > @@ -1156,12 +1162,8 @@ int vhost_init_used(struct vhost_virtqueue *vq)
> > >  {
> > >   __virtio16 last_used_idx;
> > >   int r;
> > > - if (!vq->private_data) {
> > > - vq->is_le = virtio_legacy_is_little_endian();
> > > + if (!vq->private_data)
> > >   return 0;
> > > - }
> > > -
> > > - vhost_init_is_le(vq);
> > >  
> > >   r = vhost_update_used_flags(vq);
> > >   if (r)
> > > diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
> > > index 4772862b71a7..8a62041959fe 100644
> > > --- a/drivers/vhost/vhost.h
> > > +++ b/drivers/vhost/vhost.h
> > > @@ -162,6 +162,7 @@ bool vhost_enable_notify(struct vhost_dev *, struct 
> > > vhost_virtqueue *);
> > >  
> > >  int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
> > >   unsigned int log_num, u64

Re: [PATCH] vhost: move is_le setup to the backend

2015-11-12 Thread Greg Kurz

On Fri, 30 Oct 2015 12:42:35 +0100
Greg Kurz  wrote:

> The vq->is_le field is used to fix endianness when accessing the vring via
> the cpu_to_vhost16() and vhost16_to_cpu() helpers in the following cases:
> 
> 1) host is big endian and device is modern virtio
> 
> 2) host has cross-endian support and device is legacy virtio with a different
>endianness than the host
> 
> Both cases rely on the VHOST_SET_FEATURES ioctl, but 2) also needs the
> VHOST_SET_VRING_ENDIAN ioctl to be called by userspace. Since vq->is_le
> is only needed when the backend is active, it was decided to set it at
> backend start.
> 
> This is currently done in vhost_init_used()->vhost_init_is_le() but it
> obfuscates the core vhost code. This patch moves the is_le setup to a
> dedicated function that is called from the backend code.
> 
> Note vhost_net is the only backend that can pass vq->private_data == NULL to
> vhost_init_used(), hence the "if (sock)" branch.
> 
> No behaviour change.
> 
> Signed-off-by: Greg Kurz 
> ---

Ping ?

>  drivers/vhost/net.c   |6 ++
>  drivers/vhost/scsi.c  |3 +++
>  drivers/vhost/test.c  |2 ++
>  drivers/vhost/vhost.c |   12 +++-
>  drivers/vhost/vhost.h |1 +
>  5 files changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 9eda69e40678..d6319cb2664c 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -917,6 +917,12 @@ static long vhost_net_set_backend(struct vhost_net *n, 
> unsigned index, int fd)
> 
>   vhost_net_disable_vq(n, vq);
>   vq->private_data = sock;
> +
> + if (sock)
> + vhost_set_is_le(vq);
> + else
> + vq->is_le = virtio_legacy_is_little_endian();
> +
>   r = vhost_init_used(vq);
>   if (r)
>   goto err_used;
> diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
> index e25a23692822..e2644a301fa5 100644
> --- a/drivers/vhost/scsi.c
> +++ b/drivers/vhost/scsi.c
> @@ -1276,6 +1276,9 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
>   vq = >vqs[i].vq;
>   mutex_lock(>mutex);
>   vq->private_data = vs_tpg;
> +
> + vhost_set_is_le(vq);
> +
>   vhost_init_used(vq);
>   mutex_unlock(>mutex);
>   }
> diff --git a/drivers/vhost/test.c b/drivers/vhost/test.c
> index f2882ac98726..b1c7df502211 100644
> --- a/drivers/vhost/test.c
> +++ b/drivers/vhost/test.c
> @@ -196,6 +196,8 @@ static long vhost_test_run(struct vhost_test *n, int test)
>   oldpriv = vq->private_data;
>   vq->private_data = priv;
> 
> + vhost_set_is_le(vq);
> +
>   r = vhost_init_used(>vqs[index]);
> 
>   mutex_unlock(>mutex);
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index eec2f11809ff..6be863dcbd13 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -113,6 +113,12 @@ static void vhost_init_is_le(struct vhost_virtqueue *vq)
>  }
>  #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
> 
> +void vhost_set_is_le(struct vhost_virtqueue *vq)
> +{
> + vhost_init_is_le(vq);
> +}
> +EXPORT_SYMBOL_GPL(vhost_set_is_le);
> +
>  static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
>   poll_table *pt)
>  {
> @@ -1156,12 +1162,8 @@ int vhost_init_used(struct vhost_virtqueue *vq)
>  {
>   __virtio16 last_used_idx;
>   int r;
> - if (!vq->private_data) {
> - vq->is_le = virtio_legacy_is_little_endian();
> + if (!vq->private_data)
>   return 0;
> - }
> -
> - vhost_init_is_le(vq);
> 
>   r = vhost_update_used_flags(vq);
>   if (r)
> diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
> index 4772862b71a7..8a62041959fe 100644
> --- a/drivers/vhost/vhost.h
> +++ b/drivers/vhost/vhost.h
> @@ -162,6 +162,7 @@ bool vhost_enable_notify(struct vhost_dev *, struct 
> vhost_virtqueue *);
> 
>  int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
>   unsigned int log_num, u64 len);
> +void vhost_set_is_le(struct vhost_virtqueue *vq);
> 
>  #define vq_err(vq, fmt, ...) do {  \
>   pr_debug(pr_fmt(fmt), ##__VA_ARGS__);   \
> 
> --
> To unsubscribe from this list: send the line "unsubscribe kvm" in
> the body of a message to majord...@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 

___
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization

Re: [PATCH] vhost: move is_le setup to the backend

2015-11-12 Thread Cornelia Huck

On Fri, 30 Oct 2015 12:42:35 +0100
Greg Kurz  wrote:

> The vq->is_le field is used to fix endianness when accessing the vring via
> the cpu_to_vhost16() and vhost16_to_cpu() helpers in the following cases:
> 
> 1) host is big endian and device is modern virtio
> 
> 2) host has cross-endian support and device is legacy virtio with a different
>endianness than the host
> 
> Both cases rely on the VHOST_SET_FEATURES ioctl, but 2) also needs the
> VHOST_SET_VRING_ENDIAN ioctl to be called by userspace. Since vq->is_le
> is only needed when the backend is active, it was decided to set it at
> backend start.
> 
> This is currently done in vhost_init_used()->vhost_init_is_le() but it
> obfuscates the core vhost code. This patch moves the is_le setup to a
> dedicated function that is called from the backend code.
> 
> Note vhost_net is the only backend that can pass vq->private_data == NULL to
> vhost_init_used(), hence the "if (sock)" branch.
> 
> No behaviour change.
> 
> Signed-off-by: Greg Kurz 
> ---
>  drivers/vhost/net.c   |6 ++
>  drivers/vhost/scsi.c  |3 +++
>  drivers/vhost/test.c  |2 ++
>  drivers/vhost/vhost.c |   12 +++-
>  drivers/vhost/vhost.h |1 +
>  5 files changed, 19 insertions(+), 5 deletions(-)

Makes sense.

Reviewed-by: Cornelia Huck 

___
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization

Re: [PATCH] vhost: move is_le setup to the backend

2015-11-12 Thread Michael S. Tsirkin

On Fri, Oct 30, 2015 at 12:42:35PM +0100, Greg Kurz wrote:
> The vq->is_le field is used to fix endianness when accessing the vring via
> the cpu_to_vhost16() and vhost16_to_cpu() helpers in the following cases:
> 
> 1) host is big endian and device is modern virtio
> 
> 2) host has cross-endian support and device is legacy virtio with a different
>endianness than the host
> 
> Both cases rely on the VHOST_SET_FEATURES ioctl, but 2) also needs the
> VHOST_SET_VRING_ENDIAN ioctl to be called by userspace. Since vq->is_le
> is only needed when the backend is active, it was decided to set it at
> backend start.
> 
> This is currently done in vhost_init_used()->vhost_init_is_le() but it
> obfuscates the core vhost code. This patch moves the is_le setup to a
> dedicated function that is called from the backend code.
> 
> Note vhost_net is the only backend that can pass vq->private_data == NULL to
> vhost_init_used(), hence the "if (sock)" branch.
> 
> No behaviour change.
> 
> Signed-off-by: Greg Kurz 

I plan to look at this next week, busy with QEMU 2.5 now.

> ---
>  drivers/vhost/net.c   |6 ++
>  drivers/vhost/scsi.c  |3 +++
>  drivers/vhost/test.c  |2 ++
>  drivers/vhost/vhost.c |   12 +++-
>  drivers/vhost/vhost.h |1 +
>  5 files changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 9eda69e40678..d6319cb2664c 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -917,6 +917,12 @@ static long vhost_net_set_backend(struct vhost_net *n, 
> unsigned index, int fd)
>  
>   vhost_net_disable_vq(n, vq);
>   vq->private_data = sock;
> +
> + if (sock)
> + vhost_set_is_le(vq);
> + else
> + vq->is_le = virtio_legacy_is_little_endian();
> +
>   r = vhost_init_used(vq);
>   if (r)
>   goto err_used;
> diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
> index e25a23692822..e2644a301fa5 100644
> --- a/drivers/vhost/scsi.c
> +++ b/drivers/vhost/scsi.c
> @@ -1276,6 +1276,9 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
>   vq = >vqs[i].vq;
>   mutex_lock(>mutex);
>   vq->private_data = vs_tpg;
> +
> + vhost_set_is_le(vq);
> +
>   vhost_init_used(vq);
>   mutex_unlock(>mutex);
>   }
> diff --git a/drivers/vhost/test.c b/drivers/vhost/test.c
> index f2882ac98726..b1c7df502211 100644
> --- a/drivers/vhost/test.c
> +++ b/drivers/vhost/test.c
> @@ -196,6 +196,8 @@ static long vhost_test_run(struct vhost_test *n, int test)
>   oldpriv = vq->private_data;
>   vq->private_data = priv;
>  
> + vhost_set_is_le(vq);
> +
>   r = vhost_init_used(>vqs[index]);
>  
>   mutex_unlock(>mutex);
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index eec2f11809ff..6be863dcbd13 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -113,6 +113,12 @@ static void vhost_init_is_le(struct vhost_virtqueue *vq)
>  }
>  #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
>  
> +void vhost_set_is_le(struct vhost_virtqueue *vq)
> +{
> + vhost_init_is_le(vq);
> +}
> +EXPORT_SYMBOL_GPL(vhost_set_is_le);
> +
>  static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
>   poll_table *pt)
>  {
> @@ -1156,12 +1162,8 @@ int vhost_init_used(struct vhost_virtqueue *vq)
>  {
>   __virtio16 last_used_idx;
>   int r;
> - if (!vq->private_data) {
> - vq->is_le = virtio_legacy_is_little_endian();
> + if (!vq->private_data)
>   return 0;
> - }
> -
> - vhost_init_is_le(vq);
>  
>   r = vhost_update_used_flags(vq);
>   if (r)
> diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
> index 4772862b71a7..8a62041959fe 100644
> --- a/drivers/vhost/vhost.h
> +++ b/drivers/vhost/vhost.h
> @@ -162,6 +162,7 @@ bool vhost_enable_notify(struct vhost_dev *, struct 
> vhost_virtqueue *);
>  
>  int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
>   unsigned int log_num, u64 len);
> +void vhost_set_is_le(struct vhost_virtqueue *vq);
>  
>  #define vq_err(vq, fmt, ...) do {  \
>   pr_debug(pr_fmt(fmt), ##__VA_ARGS__);   \
___
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization

Re: [PATCH] vhost: move is_le setup to the backend

2015-11-02 Thread David Miller

From: Greg Kurz 
Date: Fri, 30 Oct 2015 12:42:35 +0100

> The vq->is_le field is used to fix endianness when accessing the vring via
> the cpu_to_vhost16() and vhost16_to_cpu() helpers in the following cases:
> 
> 1) host is big endian and device is modern virtio
> 
> 2) host has cross-endian support and device is legacy virtio with a different
>endianness than the host
> 
> Both cases rely on the VHOST_SET_FEATURES ioctl, but 2) also needs the
> VHOST_SET_VRING_ENDIAN ioctl to be called by userspace. Since vq->is_le
> is only needed when the backend is active, it was decided to set it at
> backend start.
> 
> This is currently done in vhost_init_used()->vhost_init_is_le() but it
> obfuscates the core vhost code. This patch moves the is_le setup to a
> dedicated function that is called from the backend code.
> 
> Note vhost_net is the only backend that can pass vq->private_data == NULL to
> vhost_init_used(), hence the "if (sock)" branch.
> 
> No behaviour change.
> 
> Signed-off-by: Greg Kurz 

Michael, I'm assuming that you will be the one taking this.
___
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization

[PATCH] vhost: move is_le setup to the backend

2015-10-30 Thread Greg Kurz

The vq->is_le field is used to fix endianness when accessing the vring via
the cpu_to_vhost16() and vhost16_to_cpu() helpers in the following cases:

1) host is big endian and device is modern virtio

2) host has cross-endian support and device is legacy virtio with a different
   endianness than the host

Both cases rely on the VHOST_SET_FEATURES ioctl, but 2) also needs the
VHOST_SET_VRING_ENDIAN ioctl to be called by userspace. Since vq->is_le
is only needed when the backend is active, it was decided to set it at
backend start.

This is currently done in vhost_init_used()->vhost_init_is_le() but it
obfuscates the core vhost code. This patch moves the is_le setup to a
dedicated function that is called from the backend code.

Note vhost_net is the only backend that can pass vq->private_data == NULL to
vhost_init_used(), hence the "if (sock)" branch.

No behaviour change.

Signed-off-by: Greg Kurz 
---
 drivers/vhost/net.c   |6 ++
 drivers/vhost/scsi.c  |3 +++
 drivers/vhost/test.c  |2 ++
 drivers/vhost/vhost.c |   12 +++-
 drivers/vhost/vhost.h |1 +
 5 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 9eda69e40678..d6319cb2664c 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -917,6 +917,12 @@ static long vhost_net_set_backend(struct vhost_net *n, 
unsigned index, int fd)
 
vhost_net_disable_vq(n, vq);
vq->private_data = sock;
+
+   if (sock)
+   vhost_set_is_le(vq);
+   else
+   vq->is_le = virtio_legacy_is_little_endian();
+
r = vhost_init_used(vq);
if (r)
goto err_used;
diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
index e25a23692822..e2644a301fa5 100644
--- a/drivers/vhost/scsi.c
+++ b/drivers/vhost/scsi.c
@@ -1276,6 +1276,9 @@ vhost_scsi_set_endpoint(struct vhost_scsi *vs,
vq = >vqs[i].vq;
mutex_lock(>mutex);
vq->private_data = vs_tpg;
+
+   vhost_set_is_le(vq);
+
vhost_init_used(vq);
mutex_unlock(>mutex);
}
diff --git a/drivers/vhost/test.c b/drivers/vhost/test.c
index f2882ac98726..b1c7df502211 100644
--- a/drivers/vhost/test.c
+++ b/drivers/vhost/test.c
@@ -196,6 +196,8 @@ static long vhost_test_run(struct vhost_test *n, int test)
oldpriv = vq->private_data;
vq->private_data = priv;
 
+   vhost_set_is_le(vq);
+
r = vhost_init_used(>vqs[index]);
 
mutex_unlock(>mutex);
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index eec2f11809ff..6be863dcbd13 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -113,6 +113,12 @@ static void vhost_init_is_le(struct vhost_virtqueue *vq)
 }
 #endif /* CONFIG_VHOST_CROSS_ENDIAN_LEGACY */
 
+void vhost_set_is_le(struct vhost_virtqueue *vq)
+{
+   vhost_init_is_le(vq);
+}
+EXPORT_SYMBOL_GPL(vhost_set_is_le);
+
 static void vhost_poll_func(struct file *file, wait_queue_head_t *wqh,
poll_table *pt)
 {
@@ -1156,12 +1162,8 @@ int vhost_init_used(struct vhost_virtqueue *vq)
 {
__virtio16 last_used_idx;
int r;
-   if (!vq->private_data) {
-   vq->is_le = virtio_legacy_is_little_endian();
+   if (!vq->private_data)
return 0;
-   }
-
-   vhost_init_is_le(vq);
 
r = vhost_update_used_flags(vq);
if (r)
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index 4772862b71a7..8a62041959fe 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -162,6 +162,7 @@ bool vhost_enable_notify(struct vhost_dev *, struct 
vhost_virtqueue *);
 
 int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
unsigned int log_num, u64 len);
+void vhost_set_is_le(struct vhost_virtqueue *vq);
 
 #define vq_err(vq, fmt, ...) do {  \
pr_debug(pr_fmt(fmt), ##__VA_ARGS__);   \

___
Virtualization mailing list
Virtualization@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/virtualization

Re: [PATCH] vhost: move is_le setup to the backend

Re: [PATCH] vhost: move is_le setup to the backend

Re: [PATCH] vhost: move is_le setup to the backend

[PATCH] vhost: move is_le setup to the backend

Re: [PATCH] vhost: move is_le setup to the backend

Re: [PATCH] vhost: move is_le setup to the backend

Re: [PATCH] vhost: move is_le setup to the backend

Re: [PATCH] vhost: move is_le setup to the backend

Re: [PATCH] vhost: move is_le setup to the backend

[PATCH] vhost: move is_le setup to the backend

10 matches

Site Navigation

Mail list logo

Footer information