Patchwork virtio-net: Fix lduw_p() pointer argument of wrong size

login
register
mail settings
Submitter Stefan Hajnoczi
Date March 3, 2011, 9:42 p.m.
Message ID <1299188548-24670-1-git-send-email-stefanha@linux.vnet.ibm.com>
Download mbox | patch
Permalink /patch/85344/
State New
Headers show

Comments

Stefan Hajnoczi - March 3, 2011, 9:42 p.m.
A pointer to a size_t variable was passed as the void * pointer to
lduw_p() in virtio_net_receive().  Instead of acting on the 16-bit value
this caused failure on big-endian hosts.

Avoid this issue in the future by using stw_p() instead.  In general we
should use ld*_p() for loading from target memory and st*_p() for
storing to target memory anyway, not the other way around.

Also tighten up a correct use of lduw_p() when stw_p() should be used
instead in virtio_net_get_config().

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
---
 hw/virtio-net.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
Aurelien Jarno - March 3, 2011, 10:45 p.m.
On Thu, Mar 03, 2011 at 09:42:28PM +0000, Stefan Hajnoczi wrote:
> A pointer to a size_t variable was passed as the void * pointer to
> lduw_p() in virtio_net_receive().  Instead of acting on the 16-bit value
> this caused failure on big-endian hosts.
> 
> Avoid this issue in the future by using stw_p() instead.  In general we
> should use ld*_p() for loading from target memory and st*_p() for
> storing to target memory anyway, not the other way around.
> 
> Also tighten up a correct use of lduw_p() when stw_p() should be used
> instead in virtio_net_get_config().
> 
> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
> ---
>  hw/virtio-net.c |    4 ++--
>  1 files changed, 2 insertions(+), 2 deletions(-)

Thanks a lot for the quick patch, I confirm it fixes big endian support.
I have applied it, also to the stable branch.

> diff --git a/hw/virtio-net.c b/hw/virtio-net.c
> index 20cf680..5962298 100644
> --- a/hw/virtio-net.c
> +++ b/hw/virtio-net.c
> @@ -79,7 +79,7 @@ static void virtio_net_get_config(VirtIODevice *vdev, uint8_t *config)
>      VirtIONet *n = to_virtio_net(vdev);
>      struct virtio_net_config netcfg;
>  
> -    netcfg.status = lduw_p(&n->status);
> +    stw_p(&netcfg.status, n->status);
>      memcpy(netcfg.mac, n->mac, ETH_ALEN);
>      memcpy(config, &netcfg, sizeof(netcfg));
>  }
> @@ -679,7 +679,7 @@ static ssize_t virtio_net_receive(VLANClientState *nc, const uint8_t *buf, size_
>      }
>  
>      if (mhdr) {
> -        mhdr->num_buffers = lduw_p(&i);
> +        stw_p(&mhdr->num_buffers, i);
>      }
>  
>      virtqueue_flush(n->rx_vq, i);
> -- 
> 1.7.2.3
> 
>
Liu Yu-B13201 - March 4, 2011, 6:41 a.m.
> -----Original Message-----
> From: Aurelien Jarno [mailto:aurelien@aurel32.net] 
> Sent: Friday, March 04, 2011 6:46 AM
> To: Stefan Hajnoczi
> Cc: Liu Yu-B13201; Anthony Liguori; qemu-devel@nongnu.org
> Subject: Re: [PATCH] virtio-net: Fix lduw_p() pointer 
> argument of wrong size
> 
> On Thu, Mar 03, 2011 at 09:42:28PM +0000, Stefan Hajnoczi wrote:
> > A pointer to a size_t variable was passed as the void * pointer to
> > lduw_p() in virtio_net_receive().  Instead of acting on the 
> 16-bit value
> > this caused failure on big-endian hosts.
> > 
> > Avoid this issue in the future by using stw_p() instead.  
> In general we
> > should use ld*_p() for loading from target memory and st*_p() for
> > storing to target memory anyway, not the other way around.
> > 
> > Also tighten up a correct use of lduw_p() when stw_p() 
> should be used
> > instead in virtio_net_get_config().
> > 
> > Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
> > ---
> >  hw/virtio-net.c |    4 ++--
> >  1 files changed, 2 insertions(+), 2 deletions(-)
> 
> Thanks a lot for the quick patch, I confirm it fixes big 
> endian support.
> I have applied it, also to the stable branch.
> 

Thank you both very much. This solved my issue.

Thanks,
Yu

Patch

diff --git a/hw/virtio-net.c b/hw/virtio-net.c
index 20cf680..5962298 100644
--- a/hw/virtio-net.c
+++ b/hw/virtio-net.c
@@ -79,7 +79,7 @@  static void virtio_net_get_config(VirtIODevice *vdev, uint8_t *config)
     VirtIONet *n = to_virtio_net(vdev);
     struct virtio_net_config netcfg;
 
-    netcfg.status = lduw_p(&n->status);
+    stw_p(&netcfg.status, n->status);
     memcpy(netcfg.mac, n->mac, ETH_ALEN);
     memcpy(config, &netcfg, sizeof(netcfg));
 }
@@ -679,7 +679,7 @@  static ssize_t virtio_net_receive(VLANClientState *nc, const uint8_t *buf, size_
     }
 
     if (mhdr) {
-        mhdr->num_buffers = lduw_p(&i);
+        stw_p(&mhdr->num_buffers, i);
     }
 
     virtqueue_flush(n->rx_vq, i);