Can you please try updating WDF on the guest to version 1.11 and see if it fixes the problem?

You should be able to download the update using this link:
https://support.microsoft.com/en-us/help/2685811

Thanks!
Ladi

I updated WDF to 1.11 and that appears to have fixed the problem. Thanks.

Thank you! I believe that we started exercising the broken WDF 1.9 code only recently and this qualifies as a regression. I'll see if I can find an easy to work around it.

The problem is in 
https://github.com/Microsoft/Windows-Driver-Frameworks/blob/master/src/framework/shared/irphandlers/pnp/interruptobject.cpp#L1071 (FxInterrupt::RevokeResources)

which doesn't preserve m_InterruptInfo.MessageNumber in WDF 1.9.

I am perfectly fine with requiring WDF 1.11 for this to work, but it would be good if at least WriteFile would return an error instead of blocking so that there is at a way to give feedback to the user that there is a problem.

Hi 

QE can reproduce this bug (win2008R2, build 132)

steps:

1 boot win2008r2 guest with virtio-serial-pci (-smp 2,maxcpus=6)
  cml: -device virtio-serial-pci,id=virtio-serial0,max_ports=511 -chardev socket,id=channel1,path=/tmp/helloworld1,server,nowait -device virtserialport,chardev=channel1,name=com.redhat.rhevm.vdsm1,bus=virtio-serial0.0,id=port1,nr=1

2 run "socat - /tmp/helloworld1" in host
3 run "vmc-cat.exe w com.redhat.rhevm.vdsm1" in guest

4 Type "test1" and press ENTER inside the guest.
5 Observe "test1" is displayed on the host and the messages "Executing WriteFile" and "Finished WriteFile" are displayed in the guest
6 Type "test2" and press ENTER inside the guest.
7 Observe "test1" is displayed on the host and the messages "Executing WriteFile" and "Finished WriteFile" are displayed in the guest

8 hotadd cpu for guest in qmp
{ "execute": "device_add","arguments":{"driver":"qemu64-x86_64-cpu","core-id": "0", "thread-id": "0", "socket-id": "2","id":"core1" }}
{ "execute": "device_add","arguments":{"driver":"qemu64-x86_64-cpu","core-id": "0", "thread-id": "0", "socket-id": "3","id":"core2" }}

9 Type "test1" and press ENTER inside the guest.

Actual result:
after step 9 , "test1" can be transferred to the host, but there is no "Finished WriteFile" in the guest,just "vmc-cat.exe" hang at "Executing Writefile", cannot enter any data in this vmc-cat.exe processing.


Thanks
Yu Wang

Fixed committed as https://github.com/virtio-win/kvm-guest-drivers-windows/commit/3628672ef8beee9aa22529f2dc149609bfab810f

Reproduce this issue on build 135
Verify this issue on build 136

steps as comment#7

with build 136 on win2008R2, it could transferred to the host successfully after hotplug cpu.

Above all, this issue has been fixed. Change status to verified.


Thanks
Yu Wang

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2017:2341