Re: [PATCH] spapr: Don't allow unplug of NVLink2 devices

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 3/31/20 5:27 AM, David Gibson wrote:
> Currently, we can't properly handle unplug of NVLink2 devices, because we
> don't have code to tear down their special memory resources.  There's not
> a lot of impetus to implement that: since hardware NVLink2 devices can't
> be hot unplugged, the guest side drivers don't usually support unplug
> anyway.
> 
> Therefore, simply prevent unplug of NVLink2 devices.

Safe for 5.0, right?

Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>

> 
> Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
> ---
>   hw/ppc/spapr_pci.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
> index 55ca9dee1e..61b84a392d 100644
> --- a/hw/ppc/spapr_pci.c
> +++ b/hw/ppc/spapr_pci.c
> @@ -1665,6 +1665,10 @@ static void spapr_pci_unplug_request(HotplugHandler *plug_handler,
>               error_setg(errp, "PCI: Hot unplug of PCI bridges not supported");
>               return;
>           }
> +        if (object_property_get_uint(OBJECT(pdev), "nvlink2-tgt", NULL)) {
> +            error_setg(errp, "PCI: Cannot unplug NVLink2 devices");
> +            return;
> +        }
>   
>           /* ensure any other present functions are pending unplug */
>           if (PCI_FUNC(pdev->devfn) == 0) {
>