Jason Wang
2018-Oct-16 08:53 UTC
[PATCH] virtio_net: enable tx after resuming from suspend
On 2018/10/15 ??6:08, ake wrote:> > On 2018?10?12? 18:18, ake wrote: >> >> On 2018?10?12? 17:23, Jason Wang wrote: >>> >>> On 2018?10?12? 12:30, ake wrote: >>>> On 2018?10?11? 22:06, Jason Wang wrote: >>>>> On 2018?10?11? 18:22, ake wrote: >>>>>> On 2018?10?11? 18:44, Jason Wang wrote: >>>>>>> On 2018?10?11? 15:51, Ake Koomsin wrote: >>>>>>>> commit 713a98d90c5e ("virtio-net: serialize tx routine during reset") >>>>>>>> disabled the virtio tx before going to suspend to avoid a use after >>>>>>>> free. >>>>>>>> However, after resuming, it causes the virtio_net device to lose its >>>>>>>> network connectivity. >>>>>>>> >>>>>>>> To solve the issue, we need to enable tx after resuming. >>>>>>>> >>>>>>>> Fixes commit 713a98d90c5e ("virtio-net: serialize tx routine during >>>>>>>> reset") >>>>>>>> Signed-off-by: Ake Koomsin <ake at igel.co.jp> >>>>>>>> --- >>>>>>>> ??? drivers/net/virtio_net.c | 1 + >>>>>>>> ??? 1 file changed, 1 insertion(+) >>>>>>>> >>>>>>>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c >>>>>>>> index dab504ec5e50..3453d80f5f81 100644 >>>>>>>> --- a/drivers/net/virtio_net.c >>>>>>>> +++ b/drivers/net/virtio_net.c >>>>>>>> @@ -2256,6 +2256,7 @@ static int virtnet_restore_up(struct >>>>>>>> virtio_device *vdev) >>>>>>>> ??????? } >>>>>>>> ??? ????? netif_device_attach(vi->dev); >>>>>>>> +??? netif_start_queue(vi->dev); >>>>>>> I believe this is duplicated with netif_tx_wake_all_queues() in >>>>>>> netif_device_attach() above? >>>>>> Thank you for your review. >>>>>> >>>>>> If both netif_tx_wake_all_queues() and netif_start_queue() result in >>>>>> clearing __QUEUE_STATE_DRV_XOFF, then is it possible that some >>>>>> conditions in netif_device_attach() is not satisfied? >>>>> Yes, maybe. One case I can see now is when the device is down, in this >>>>> case netif_device_attach() won't try to wakeup the queue. >>>>> >>>>>> ?? Without >>>>>> netif_start_queue(), the virtio_net device does not resume properly >>>>>> after waking up. >>>>> How do you trigger the issue? Just do suspend/resume? >>>> Yes, simply suspend and resume. >>>> >>>> Here is how I trigger the issue: >>>> >>>> 1) Start the Virtual Machine Manager GUI program. >>>> 2) Create a guest Linux OS. Make sure that the guest OS kernel is >>>> ??? >= 4.12. Make sure that it uses virtio_net as its network device. >>>> ??? In addition, make sure that the video adapter is VGA. Otherwise, >>>> ??? waking up with the virtual power button does not work. >>>> 3) After installing the guest OS, log in, and test the network >>>> ??? connectivity by ping the host machine. >>>> 4) Suspend. After this, the screen is blank. >>>> 5) Resume by hitting the virtual power button. The login screen >>>> ??? appears again. >>>> 6) Log in again. The guest loses its network connection. >>>> >>>> In my test: >>>> Guest: Ubuntu 16.04/18.04 with kernel 4.15.0-36-generic >>>> Host: Ubuntu 16.04 with kernel 4.15.0-36-generic/4.4.0-137-generic >>> I can not reproduce this issue if virtio-net interface is up in guest >>> before the suspend. I'm using net-next.git and qemu master. But I do >>> reproduce when virtio-net interface is down in guest before suspend, >>> after resume, even if I make it up, the network is still lost. >>> >>> I think the interface is up in your case, but please confirm this. >> If you mean the interface state before I hit the suspend button, >> the answer is yes. The interface is up before I suspend the guest >> machine. >> >> Note that my current QEMU version is QEMU emulator version 2.5.0 >> (Debian 1:2.5+dfsg-5ubuntu10.32). >> >> I will try with net-next.git and qemu master later and see if I can >> reproduce the issue. > Update. I tried with net-next and qemu master. Interestingly, the result > is different from yours. The network is lost even if the virtio_net > interface is up before suspending. > > Host: Ubuntu 16.04 with net-next kernel (default configuration) > Guest: Ubuntu 18.04 with net-next kernel (default configuration) > Qemu: master > Qemu command: > qemu-system-x86_64 -cpu host -m 2048 -enable-kvm \ > -bios /usr/share/OVMF/OVMF_CODE.fd \ > -drive file=/var/lib/libvirt/images/virtio_test.qcow2,if=virtio \ > -netdev user,id=hostnet0 \ > -device virtio-net-pci,netdev=hostnet0 \ > -device VGA,id=video0,vgamem_mb=16 \ > -global PIIX4_PM.disable_s3=1 \ > -global PIIX4_PM.disable_s4=1 -monitor stdioInteresting, just notice you're using userspace network. To isolate the issue, can you retry with e.g tap or e1000 to make sure it's not a fault of slirp or virito-net? Thanks