Re: [RFC PATCH] virtio: re-order vm_running and use_started checks

[Michael S. Tsirkin]

On Fri, Nov 04, 2022 at 04:31:08PM +0000, Alex Bennée wrote:
> 
> "Michael S. Tsirkin" <mst@redhat.com> writes:
> 
> > On Fri, Oct 14, 2022 at 02:21:08PM +0100, Alex Bennée wrote:
> >> During migration the virtio device state can be restored before we
> >> restart the VM. As no devices can be running while the VM is paused it
> >> makes sense to bail out early in that case.
> >> 
> >> This returns the order introduced in:
> >> 
> >>  9f6bcfd99f (hw/virtio: move vm_running check to virtio_device_started)
> >> 
> >> to what virtio-sock was doing longhand.
> >> 
> >> Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
> >> Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
> >
> >
> > What happens now:
> >
> > with this applied I get:
> >
> > https://gitlab.com/mitsirkin/qemu/-/pipelines/685829158/failures
> >
> > ――――――――――――――――――――――――――――――――――――― ✀  
> > ―――――――――――――――――――――――――――――――――――――
> > stderr:
> > qemu-system-arm: Failed to write msg. Wrote -1 instead of 20.
> > qemu-system-arm: vhost VQ 0 ring restore failed: -22: Invalid argument (22)
> > qemu-system-arm: Failed to set msg fds.
> > qemu-system-arm: vhost VQ 1 ring restore failed: -22: Invalid argument (22)
> > qemu-system-arm: -chardev
> > socket,id=chr-reconnect,path=/tmp/vhost-test-QLKXU1/reconnect.sock,server=on:
> > info: QEMU waiting for connection on:
> > disconnected:unix:/tmp/vhost-test-QLKXU1/reconnect.sock,server=on
> > qemu-system-arm: Failed to write msg. Wrote -1 instead of 20.
> > qemu-system-arm: vhost VQ 0 ring restore failed: -22: Invalid argument (22)
> > qemu-system-arm: Failed to set msg fds.
> > qemu-system-arm: vhost VQ 1 ring restore failed: -22: Invalid argument (22)
> > qemu-system-arm: -chardev
> > socket,id=chr-connect-fail,path=/tmp/vhost-test-L9Q6U1/connect-fail.sock,server=on:
> > info: QEMU waiting for connection on:
> > disconnected:unix:/tmp/vhost-test-L9Q6U1/connect-fail.sock,server=on
> > qemu-system-arm: -netdev
> > vhost-user,id=hs0,chardev=chr-connect-fail,vhostforce=on: Failed to
> > read msg header. Read 0 instead of 12. Original request 1.
> > qemu-system-arm: -netdev
> > vhost-user,id=hs0,chardev=chr-connect-fail,vhostforce=on:
> > vhost_backend_init failed: Protocol error
> > qemu-system-arm: -netdev
> > vhost-user,id=hs0,chardev=chr-connect-fail,vhostforce=on: failed to
> > init vhost_net for queue 0
> > qemu-system-arm: -netdev
> > vhost-user,id=hs0,chardev=chr-connect-fail,vhostforce=on: info: QEMU
> > waiting for connection on:
> > disconnected:unix:/tmp/vhost-test-L9Q6U1/connect-fail.sock,server=on
> > qemu-system-arm: Failed to write msg. Wrote -1 instead of 20.
> > qemu-system-arm: vhost VQ 0 ring restore failed: -22: Invalid argument (22)
> > qemu-system-arm: Failed to set msg fds.
> > qemu-system-arm: vhost VQ 1 ring restore failed: -22: Invalid argument (22)
> > qemu-system-arm: -chardev
> > socket,id=chr-flags-mismatch,path=/tmp/vhost-test-3MO5U1/flags-mismatch.sock,server=on:
> > info: QEMU waiting for connection on:
> > disconnected:unix:/tmp/vhost-test-3MO5U1/flags-mismatch.sock,server=on
> > qemu-system-arm: Failed to write msg. Wrote -1 instead of 52.
> > qemu-system-arm: vhost_set_mem_table failed: Invalid argument (22)
> > qemu-system-arm: unable to start vhost net: 22: falling back on userspace 
> > virtio
> > vhost lacks feature mask 0x40000000 for backend
> > qemu-system-arm: failed to init vhost_net for queue 0
> > qemu-system-arm: Failed to set msg fds.
> > qemu-system-arm: vhost VQ 0 ring restore failed: -22: Invalid argument (22)
> > qemu-system-arm: Failed to set msg fds.
> > qemu-system-arm: vhost VQ 1 ring restore failed: -22: Invalid argument (22)
> > qemu-system-arm: Failed to write msg. Wrote -1 instead of 20.
> > qemu-system-arm: vhost VQ 0 ring restore failed: -22: Invalid argument (22)
> > qemu-system-arm: Failed to set msg fds.
> > qemu-system-arm: vhost VQ 1 ring restore failed: -22: Invalid argument (22)
> > qemu-system-arm: Failed to set msg fds.
> > qemu-system-arm: vhost VQ 2 ring restore failed: -22: Invalid argument (22)
> > qemu-system-arm: Failed to set msg fds.
> > qemu-system-arm: vhost VQ 3 ring restore failed: -22: Invalid argument (22)
> > qemu-system-arm: Failed to write msg. Wrote -1 instead of 20.
> > qemu-system-arm: vhost VQ 0 ring restore failed: -22: Invalid argument (22)
> > qemu-system-arm: Failed to set msg fds.
> > qemu-system-arm: vhost VQ 1 ring restore failed: -22: Invalid argument (22)
> > qemu-system-arm: Failed to write msg. Wrote -1 instead of 20.
> > qemu-system-arm: vhost VQ 0 ring restore failed: -22: Invalid argument (22)
> > qemu-system-arm: Failed to set msg fds.
> > qemu-system-arm: vhost VQ 1 ring restore failed: -22: Invalid argument (22)
> > qemu-system-arm: Failed to set msg fds.
> > qemu-system-arm: vhost VQ 0 ring restore failed: -22: Invalid argument (22)
> > qemu-system-arm: Failed to set msg fds.
> > qemu-system-arm: vhost VQ 1 ring restore failed: -22: Invalid argument (22)
> > qemu-system-arm: Failed to set msg fds.
> > qemu-system-arm: vhost_set_vring_call failed: Invalid argument (22)
> > qemu-system-arm: Failed to set msg fds.
> > qemu-system-arm: vhost_set_vring_call failed: Invalid argument (22)
> > qemu-system-arm: Failed to write msg. Wrote -1 instead of 20.
> > qemu-system-arm: vhost VQ 0 ring restore failed: -5: Input/output error (5)
> > qemu-system-arm: ../hw/virtio/virtio-bus.c:211: void
> > virtio_bus_release_ioeventfd(VirtioBusState *): Assertion
> > `bus->ioeventfd_grabbed != 0' failed.
> > ../tests/qtest/libqtest.c:188: kill_qemu() detected QEMU death from signal 
> > 6 (Aborted) (core dumped)
> > **
> > ERROR:../tests/qtest/qos-test.c:191:subprocess_run_one_test: child
> > process
> > (/arm/virt/virtio-mmio/virtio-bus/vhost-user-gpio-device/vhost-user-gpio/vhost-user-gpio-tests/read-guest-mem/memfile/subprocess
> > [8735]) failed unexpectedly
> > (test program exited with status code -6)
> > ――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――
> >
> >
> >
> >
> > without this it passes:
> >
> > https://gitlab.com/mitsirkin/qemu/-/jobs/3275949777
> >
> >
> > this only triggers under github, clang-system job.
> > trying to decide what to do now. revert just this?
> 
> I must admit I didn't run that directly. My build box is currently out
> of commission but can we get more detail about the abort?

Just run it under gitlab. The only trick is to set QEMU_CI to 1
when running the pipeline.


> It looks like the vhost negotiation is totally broken and can't even
> find the VQs

Donnu really. I'm trying to figure out what kind of revert gets
a working tree.


> >
> >
> >> ---
> >>  include/hw/virtio/virtio.h | 8 ++++----
> >>  1 file changed, 4 insertions(+), 4 deletions(-)
> >> 
> >> diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
> >> index f41b4a7e64..ebb58feaac 100644
> >> --- a/include/hw/virtio/virtio.h
> >> +++ b/include/hw/virtio/virtio.h
> >> @@ -385,14 +385,14 @@ static inline bool virtio_is_big_endian(VirtIODevice 
> >> *vdev)
> >>  
> >>  static inline bool virtio_device_started(VirtIODevice *vdev, uint8_t 
> >> status)
> >>  {
> >> -    if (vdev->use_started) {
> >> -        return vdev->started;
> >> -    }
> >> -
> >>      if (!vdev->vm_running) {
> >>          return false;
> >>      }
> >>  
> >> +    if (vdev->use_started) {
> >> +        return vdev->started;
> >> +    }
> >> +
> >>      return status & VIRTIO_CONFIG_S_DRIVER_OK;
> >>  }
> >>  
> >> -- 
> >> 2.34.1
> 
> 
> -- 
> Alex Bennée