Re: [PATCH 1/4] hw/xen: only remove peers of PCI NICs on unplug

[David Woodhouse <dwmw2@xxxxxxxxxxxxx>]

On Tue, 2023-10-24 at 15:32 +0100, Paul Durrant wrote:
> On 17/10/2023 19:25, David Woodhouse wrote:
> > From: David Woodhouse <dwmw@xxxxxxxxxxxx>
> > 
> > When the Xen guest asks to unplug *emulated* NICs, it's kind of unhelpful
> > also to unplug the peer of the *Xen* PV NIC.
> > 
> > Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
> > ---
> >    hw/i386/xen/xen_platform.c | 9 +++++++--
> >    1 file changed, 7 insertions(+), 2 deletions(-)
> > 
> > diff --git a/hw/i386/xen/xen_platform.c b/hw/i386/xen/xen_platform.c
> > index 17457ff3de..e2dd1b536a 100644
> > --- a/hw/i386/xen/xen_platform.c
> > +++ b/hw/i386/xen/xen_platform.c
> > @@ -140,9 +140,14 @@ static void unplug_nic(PCIBus *b, PCIDevice *d, void 
> > *o)
> >    /* Remove the peer of the NIC device. Normally, this would be a tap 
> > device. */
> >    static void del_nic_peer(NICState *nic, void *opaque)
> >    {
> > -    NetClientState *nc;
> > +    NetClientState *nc = qemu_get_queue(nic);
> > +    ObjectClass *klass = module_object_class_by_name(nc->model);
> > +
> > +    /* Only delete peers of PCI NICs that we're about to delete */
> > +    if (!klass || !object_class_dynamic_cast(klass, TYPE_PCI_DEVICE)) {
> 
> Would it not be better to test for object_class_dynamic_cast(klass, 
> TYPE_XEN_DEVICE)?

Only if we also change the actual unplug to destroy non-PCI devices too.

The only non-PCI device you could have here is an ISA NE2000, I think.

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