Re: [Qemu-devel] [RFC PATCH V2 09/10] Qemu/VFIO: Add SRIOV VF migration support

[Lan, Tianyu]

On 11/25/2015 5:03 AM, Michael S. Tsirkin wrote:
> > >+void vfio_migration_cap_handle(PCIDevice *pdev, uint32_t addr,
> > >+                                  uint32_t val, int len)
> > >+{
> > >+    VFIOPCIDevice *vdev = DO_UPCAST(VFIOPCIDevice, pdev, pdev);
> > >+
> > >+    if (addr == vdev->migration_cap + PCI_VF_MIGRATION_VF_STATUS
> > >+        && val == PCI_VF_READY_FOR_MIGRATION) {
> > >+        qemu_event_set(&migration_event);
> This would wake migration so it can proceed -
> except it needs QEMU lock to run, and that's
> taken by the migration thread.

Sorry, I seem to miss something.
Which lock may cause dead lock when calling vfio_migration_cap_handle()
and run migration?
The function is called when VF accesses faked PCI capability.

> It seems unlikely that this ever worked - how
> did you test this?