[Qemu-devel] [PATCH v2] virtio-net: count VIRTIO_NET_F_MAC when calculating config_len

[Qemu-devel] [PATCH v2] virtio-net: count VIRTIO_NET_F_MAC when calculating config_len

[Jason Wang]

Commit 14f9b664 (hw/virtio-net.c: set config size using host features) tries to
calculate config size based on the host features. But it forgets the
VIRTIO_NET_F_MAC were always set for qemu later. This will lead a zero config
len for virtio-net device when both VIRTIO_NET_F_STATUS and VIRTIO_NET_F_MQ were
disabled form command line. Then qemu will crash when user tries to read the
config of virtio-net.

Fix this by counting VIRTIO_NET_F_MAC and make sure the config at least contains
the mac address.

Cc: Jesse Larrew <jlarrew@linux.vnet.ibm.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
---
Changes from V1:
- Set VIRTIO_NET_F_MAC bit in host_features instead of initializing config_size
---
 hw/net/virtio-net.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index 1662f46..d4533d5 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -1266,6 +1266,7 @@ static void virtio_net_guest_notifier_mask(VirtIODevice *vdev, int idx,
 void virtio_net_set_config_size(VirtIONet *n, uint32_t host_features)
 {
     int i, config_size = 0;
+    host_features |= (1 << VIRTIO_NET_F_MAC);
     for (i = 0; feature_sizes[i].flags != 0; i++) {
         if (host_features & feature_sizes[i].flags) {
             config_size = MAX(feature_sizes[i].end, config_size);
-- 
1.7.1

Re: [Qemu-devel] [PATCH v2] virtio-net: count VIRTIO_NET_F_MAC when calculating config_len

[Michael S. Tsirkin]

On Thu, Apr 25, 2013 at 03:26:54PM +0800, Jason Wang wrote:
> Commit 14f9b664 (hw/virtio-net.c: set config size using host features) tries to
> calculate config size based on the host features. But it forgets the
> VIRTIO_NET_F_MAC were always set for qemu later. This will lead a zero config
> len for virtio-net device when both VIRTIO_NET_F_STATUS and VIRTIO_NET_F_MQ were
> disabled form command line. Then qemu will crash when user tries to read the
> config of virtio-net.
> 
> Fix this by counting VIRTIO_NET_F_MAC and make sure the config at least contains
> the mac address.
> 
> Cc: Jesse Larrew <jlarrew@linux.vnet.ibm.com>
> Signed-off-by: Jason Wang <jasowang@redhat.com>

Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>

Not sure which tag is needed anymore ...
Anthony, pick this up for 1.5?


> ---
> Changes from V1:
> - Set VIRTIO_NET_F_MAC bit in host_features instead of initializing config_size
> ---
>  hw/net/virtio-net.c |    1 +
>  1 files changed, 1 insertions(+), 0 deletions(-)
> 
> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
> index 1662f46..d4533d5 100644
> --- a/hw/net/virtio-net.c
> +++ b/hw/net/virtio-net.c
> @@ -1266,6 +1266,7 @@ static void virtio_net_guest_notifier_mask(VirtIODevice *vdev, int idx,
>  void virtio_net_set_config_size(VirtIONet *n, uint32_t host_features)
>  {
>      int i, config_size = 0;
> +    host_features |= (1 << VIRTIO_NET_F_MAC);
>      for (i = 0; feature_sizes[i].flags != 0; i++) {
>          if (host_features & feature_sizes[i].flags) {
>              config_size = MAX(feature_sizes[i].end, config_size);
> -- 
> 1.7.1

Re: [Qemu-devel] [PATCH v2] virtio-net: count VIRTIO_NET_F_MAC when calculating config_len

[Anthony Liguori]

Applied.  Thanks.

Regards,

Anthony Liguori