On Thu, 26 Mar 2020 16:40:09 +1100
David Gibson <da...@gibson.dropbear.id.au> 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.
>
This could maybe considered as a valid fix for 5.0 since this prevents
guest crashes IIUC. But since this requires the two preliminary cleanup
patches, I understand you may prefer to postpone that to 5.1.
> Signed-off-by: David Gibson <da...@gibson.dropbear.id.au>
> ---
Reviewed-by: Greg Kurz <gr...@kaod.org>
> hw/ppc/spapr_pci.c | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c
> index 55ca9dee1e..5c8262413a 100644
> --- a/hw/ppc/spapr_pci.c
> +++ b/hw/ppc/spapr_pci.c
> @@ -1666,6 +1666,11 @@ static void spapr_pci_unplug_request(HotplugHandler
> *plug_handler,
> return;
> }
>
> + if (spapr_phb_is_nvlink_dev(pdev, phb)) {
> + error_setg(errp, "PCI: Cannot unplug NVLink2 devices");
> + return;
> + }
> +
> /* ensure any other present functions are pending unplug */
> if (PCI_FUNC(pdev->devfn) == 0) {
> for (i = 1; i < 8; i++) {
