[RFC for-5.1 4/4] spapr: Don't allow unplug of NVLink2 devices

[David Gibson <david@gibson.dropbear.id.au>]

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.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 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++) {
-- 
2.25.1