Message ID | 1426831670-11080-1-git-send-email-jasowang@redhat.com |
---|---|
State | New |
Headers | show |
On Fri, Mar 20, 2015 at 02:07:50PM +0800, Jason Wang wrote: > We don't validate the backend queue numbers against bus limitation, > this will easily crash qemu if it exceeds the limitation which will > hit the abort() in virtio_del_queue(). An example is trying to > starting a virtio-net device with 256 queues. E.g: > > ./qemu-system-x86_64 -netdev tap,id=hn0,queues=256 -device > virtio-net-pci,netdev=hn0 > > Fixing this by doing the validation and fail early. > > Cc: Michael S. Tsirkin <mst@redhat.com> > Cc: qemu-stable <qemu-stable@nongnu.org> > Signed-off-by: Jason Wang <jasowang@redhat.com> > --- > Changes from V1: > Tweak the commit log. > --- > hw/net/virtio-net.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > index 27adcc5..59f76bc 100644 > --- a/hw/net/virtio-net.c > +++ b/hw/net/virtio-net.c > @@ -1588,6 +1588,13 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp) > virtio_init(vdev, "virtio-net", VIRTIO_ID_NET, n->config_size); > > n->max_queues = MAX(n->nic_conf.peers.queues, 1); > + if (n->max_queues * 2 + 1 > VIRTIO_PCI_QUEUE_MAX) { > + error_setg(errp, "Invalid number of queues (= %" PRIu32 "), " > + "must be a postive integer less than %d.", > + n->max_queues, (VIRTIO_PCI_QUEUE_MAX - 1) / 2); > + virtio_cleanup(vdev); > + return; > + } If VIRTIO_PCI_QUEUE_MAX is really PCI-only then this is a layering violation. Virtio devices should not assume a particular transport (PCI, CCW, etc). Either the constant should be renamed if it truly applies to all transports, or there should be a virtio_get_max_queues() function that lets the transport pick a value. That said, virtio-scsi.c already checks VIRTIO_PCI_QUEUE_MAX so maybe this patch is fine and a cleanup should be written later: Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
On Mon, Mar 23, 2015 at 01:20:28PM +0000, Stefan Hajnoczi wrote: > On Fri, Mar 20, 2015 at 02:07:50PM +0800, Jason Wang wrote: > > We don't validate the backend queue numbers against bus limitation, > > this will easily crash qemu if it exceeds the limitation which will > > hit the abort() in virtio_del_queue(). An example is trying to > > starting a virtio-net device with 256 queues. E.g: > > > > ./qemu-system-x86_64 -netdev tap,id=hn0,queues=256 -device > > virtio-net-pci,netdev=hn0 > > > > Fixing this by doing the validation and fail early. > > > > Cc: Michael S. Tsirkin <mst@redhat.com> > > Cc: qemu-stable <qemu-stable@nongnu.org> > > Signed-off-by: Jason Wang <jasowang@redhat.com> > > --- > > Changes from V1: > > Tweak the commit log. > > --- > > hw/net/virtio-net.c | 7 +++++++ > > 1 file changed, 7 insertions(+) > > > > diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c > > index 27adcc5..59f76bc 100644 > > --- a/hw/net/virtio-net.c > > +++ b/hw/net/virtio-net.c > > @@ -1588,6 +1588,13 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp) > > virtio_init(vdev, "virtio-net", VIRTIO_ID_NET, n->config_size); > > > > n->max_queues = MAX(n->nic_conf.peers.queues, 1); > > + if (n->max_queues * 2 + 1 > VIRTIO_PCI_QUEUE_MAX) { > > + error_setg(errp, "Invalid number of queues (= %" PRIu32 "), " > > + "must be a postive integer less than %d.", > > + n->max_queues, (VIRTIO_PCI_QUEUE_MAX - 1) / 2); > > + virtio_cleanup(vdev); > > + return; > > + } > > If VIRTIO_PCI_QUEUE_MAX is really PCI-only then this is a layering > violation. Virtio devices should not assume a particular transport > (PCI, CCW, etc). > > Either the constant should be renamed if it truly applies to all > transports, or there should be a virtio_get_max_queues() function that > lets the transport pick a value. > > That said, virtio-scsi.c already checks VIRTIO_PCI_QUEUE_MAX so maybe > this patch is fine and a cleanup should be written later: > > Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Yes, we need to rename this constant, no problem here.
diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c index 27adcc5..59f76bc 100644 --- a/hw/net/virtio-net.c +++ b/hw/net/virtio-net.c @@ -1588,6 +1588,13 @@ static void virtio_net_device_realize(DeviceState *dev, Error **errp) virtio_init(vdev, "virtio-net", VIRTIO_ID_NET, n->config_size); n->max_queues = MAX(n->nic_conf.peers.queues, 1); + if (n->max_queues * 2 + 1 > VIRTIO_PCI_QUEUE_MAX) { + error_setg(errp, "Invalid number of queues (= %" PRIu32 "), " + "must be a postive integer less than %d.", + n->max_queues, (VIRTIO_PCI_QUEUE_MAX - 1) / 2); + virtio_cleanup(vdev); + return; + } n->vqs = g_malloc0(sizeof(VirtIONetQueue) * n->max_queues); n->vqs[0].rx_vq = virtio_add_queue(vdev, 256, virtio_net_handle_rx); n->curr_queues = 1;
We don't validate the backend queue numbers against bus limitation, this will easily crash qemu if it exceeds the limitation which will hit the abort() in virtio_del_queue(). An example is trying to starting a virtio-net device with 256 queues. E.g: ./qemu-system-x86_64 -netdev tap,id=hn0,queues=256 -device virtio-net-pci,netdev=hn0 Fixing this by doing the validation and fail early. Cc: Michael S. Tsirkin <mst@redhat.com> Cc: qemu-stable <qemu-stable@nongnu.org> Signed-off-by: Jason Wang <jasowang@redhat.com> --- Changes from V1: Tweak the commit log. --- hw/net/virtio-net.c | 7 +++++++ 1 file changed, 7 insertions(+)