add regression fix for migration with virtio-rng device

between QEMU less than 7.2 and QEMU 7.2 without the fix (both
directions are affected).

As mentioned in the patch message, this fix itself will break
migration between QEMU 7.2 and QEMU 7.2 with the fix (in both
directions, if a virtio-rng device is attached), but this is fine,
because no pve-qemu-kvm package with QEMU 7.2 has been publicly
released yet.

Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>

debian/patches/extra/0006-virtio-rng-pci-fix-migration-compat-for-vectors.patch

@@ -0,0 +1,42 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
+Date: Mon, 9 Jan 2023 10:58:09 +0000
+Subject: [PATCH] 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")
+
+Reviewed-by: Thomas Huth <thuth@redhat.com>
+Acked-by: David Daney <david.daney@fungible.com>
+Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
+(picked-up from https://lists.nongnu.org/archive/html/qemu-devel/2023-01/msg01319.html)
+Signed-off-by: Fiona Ebner <f.ebner@proxmox.com>
+---
+ hw/core/machine.c | 1 +
+ 1 file changed, 1 insertion(+)
+
+diff --git a/hw/core/machine.c b/hw/core/machine.c
+index 8d34caa31d..77a0a131d1 100644
+--- a/hw/core/machine.c
++++ b/hw/core/machine.c
+@@ -42,6 +42,7 @@
+ 
+ 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);
+ 

debian/patches/series

@@ -3,6 +3,7 @@ extra/0002-init-daemonize-defuse-PID-file-resolve-error.patch
 extra/0003-virtio-mem-Fix-the-bitmap-index-of-the-section-offse.patch
 extra/0004-virtio-mem-Fix-the-iterator-variable-in-a-vmem-rdl_l.patch
 extra/0005-vhost-fix-vq-dirty-bitmap-syncing-when-vIOMMU-is-ena.patch
+extra/0006-virtio-rng-pci-fix-migration-compat-for-vectors.patch
 bitmap-mirror/0001-drive-mirror-add-support-for-sync-bitmap-mode-never.patch
 bitmap-mirror/0002-drive-mirror-add-support-for-conditional-and-always-.patch
 bitmap-mirror/0003-mirror-add-check-for-bitmap-mode-without-bitmap.patch