virtio-rng-pci: fix migration compat for vectors

Fixup the migration compatibility for existing machine types
so that they do not enable msi-x.

Symptom:

(qemu) qemu: get_pci_config_device: Bad config data: i=0x34 read: 84 device: 98 cmask: ff wmask: 0 w1cmask:0
qemu: Failed to load PCIDevice:config
qemu: Failed to load virtio-rng:virtio
qemu: error while loading state for instance 0x0 of device '0000:00:03.0/virtio-rng'
qemu: load of migration failed: Invalid argument

Note: This fix will break migration from 7.2->7.2-fixed with this patch

bz: https://bugzilla.redhat.com/show_bug.cgi?id=2155749
Fixes: 9ea02e8f1 ("virtio-rng-pci: Allow setting nvectors, so we can use MSI-X")

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20230109105809.163975-1-dgilbert@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Acked-by: David Daney <david.daney@fungible.com>
Fixes: 9ea02e8f1 (&quot;virtio-rng-pci: Allow setting nvectors, so we can use MSI-X&quot;)<br>
Signed-off-by: Dr. David Alan Gilbert &lt;<a href="mailto:dgilbert@redhat.com" target="_blank">dgilbert@redhat.com</a>&gt;<br>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

1 files changed, 1 insertions, 0 deletions

diff --git a/hw/core/machine.c b/hw/core/machine.c
index 616f3a207c..f7761baab5 100644
--- a/hw/core/machine.c
+++ b/hw/core/machine.c
@@ -46,6 +46,7 @@ const size_t hw_compat_7_2_len = G_N_ELEMENTS(hw_compat_7_2);
 
 GlobalProperty hw_compat_7_1[] = {
     { "virtio-device", "queue_reset", "false" },
+    { "virtio-rng-pci", "vectors", "0" },
 };
 const size_t hw_compat_7_1_len = G_N_ELEMENTS(hw_compat_7_1);