Re: [Qemu-devel] [PATCH 0/4] qdev: switch reset to post-order, clean up PCI reset

[Paolo Bonzini <pbonzini@redhat.com>]

Il 06/10/2013 20:28, Michael S. Tsirkin ha scritto:
> > > > For each PCI device I tried creating a VM with an instance of it (a few
> > > > devices at a time), and did VM resets.  Earlier versions were tested by
> > > > the guy who reported the SCSI problems.
> > > 
> > > x86 kvm only?
> > 
> > Yes.
> 
> Hmm, I'm not sure that's enough for this kind of change.

I'll do more tests though, from looking at the source code, I'm not sure
what could happen depending on the host bridge.  To make it clearer, the
difference is that pre-patch you have

    device-level reset for device 1
    bus-level reset for device 1
    device-level reset for device 2
    bus-level reset for device 2
    device-level reset for device 3
    bus-level reset for device 3

and afterwards you have

    device-level reset for device 1
    device-level reset for device 2
    device-level reset for device 3
    bus-level reset for device 1
    bus-level reset for device 2
    bus-level reset for device 3

I could also preserve exactly the same semantics if you prefer.  The
patch is a bit more complicated, but it's doable.

Paolo