Re: [Qemu-devel] [PATCH 3/3] apic: always update the in-kernel status after loading

[Paolo Bonzini]

Il 30/10/2012 19:21, Jan Kiszka ha scritto:
> > > Aren't we still dependent on the order of processing?  If the APIC is
> > > restored after the device, won't we get the same problem?
> > 
> > Strictly speaking yes, but CPUs and APICs are always the first devices
> > to be saved.
> Hmm, thinking about this again: Why is the MSI event injected at all
> during restore, specifically while the device models are in transitional
> state. Can you explain this?

Because the (virtio-serial) port was connected on the source and
disconnected on the destination, or vice versa.

In my simplified reproducer, I'm really using different command-lines on
the source and destination, but it is not necessary.  For example, if
you have a socket backend, the destination will usually be disconnected
at the time the machine loads.

One alternative fix is a vm_clock timer that expires immediately.  It
would fix both MSI and INTx, on the other hand I thought it was an APIC
bug because the QEMU APIC works nicely.

> Does the same pattern then also apply on INTx injection?

Yes.

Paolo