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

[Paul Durrant]

On 17/10/2023 19:25, David Woodhouse wrote:
> From: David Woodhouse <dwmw@amazon.co.uk>
>
> 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@amazon.co.uk>
> ---
>   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)?

  Paul

> +        return;
> +    }
>   
> -    nc = qemu_get_queue(nic);
>       if (nc->peer)
>           qemu_del_net_client(nc->peer);
>   }