From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:59163) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UVGGx-0006bO-MZ for qemu-devel@nongnu.org; Thu, 25 Apr 2013 03:07:22 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1UVGGr-0007oX-3Z for qemu-devel@nongnu.org; Thu, 25 Apr 2013 03:07:15 -0400 Received: from mx1.redhat.com ([209.132.183.28]:62042) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1UVGGq-0007oP-S1 for qemu-devel@nongnu.org; Thu, 25 Apr 2013 03:07:09 -0400 Date: Thu, 25 Apr 2013 10:06:56 +0300 From: "Michael S. Tsirkin" Message-ID: <20130425070656.GA7485@redhat.com> References: <1366870889-950-1-git-send-email-jasowang@redhat.com> <20130425065953.GB7299@redhat.com> <5178D514.5090600@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5178D514.5090600@redhat.com> Subject: Re: [Qemu-devel] [PATCH] virtio-net: count VIRTIO_NET_F_MAC when calculating config_len List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jason Wang Cc: aliguori@us.ibm.com, qemu-devel@nongnu.org, Jesse Larrew On Thu, Apr 25, 2013 at 03:02:44PM +0800, Jason Wang wrote: > On 04/25/2013 02:59 PM, Michael S. Tsirkin wrote: > > On Thu, Apr 25, 2013 at 02:21:29PM +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 > >> Signed-off-by: Jason Wang > >> --- > >> hw/net/virtio-net.c | 3 ++- > >> 1 files changed, 2 insertions(+), 1 deletions(-) > >> > >> diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > >> index 70c8fce..33a70ef 100644 > >> --- a/hw/net/virtio-net.c > >> +++ b/hw/net/virtio-net.c > >> @@ -1264,7 +1264,8 @@ 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; > >> + /* VIRTIO_NET_F_MAC can't be disabled from qemu side */ > >> + int i, config_size = feature_sizes[0].end; > > This would be cleaner: > > host_features |= (1 << VIRTIO_NET_F_MAC); > > > > no need for a comment then. > > Sure, will send V2. Maybe ass assert(config_size) in core just to make sure other devices do not have this bug. > >> 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