8:09 a.m.
In the domain XML we generate, we do not assign PCI B/D/F addresses to
devices; that job is left to libvirtd. When using the Q35 machine type,
libvirtd places the virtio devices into PCI Express Root Ports. As a
consequence, QEMU disables virtio-0.9.5 support on these devices, and so
guest OSes without virtio-1.0 drivers cannot drive them.
Prevent QEMU from turning off the virtio-0.9.5 ("legacy") protocol by
specifying the "virtio-transitional" (not "virtio") model for our
virtio
devices:
- For non-disk devices, simply change the value of the existent "model"
attribute.
- For disk devices, add the "model" attribute as a new one.
(In fact, libvirtd doesn't (only) add the "disable_legacy=off" QEMU device
property for the "virtio-transitional" devices -- libvirtd even moves
these devices from PCI Express Root Ports to a dedicated
"pcie-to-pci-bridge". This has the same effect on QEMU.)
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1942325
Signed-off-by: Laszlo Ersek <lersek(a)redhat.com>
---
Notes:
At this point, this patch is unobservable on the domain XML (by intent).
output/create_libvirt_xml.ml | 28 +++++++++++++-------
1 file changed, 18 insertions(+), 10 deletions(-)
diff --git a/output/create_libvirt_xml.ml b/output/create_libvirt_xml.ml
index 9413cc0bf884..87bfab178a94 100644
--- a/output/create_libvirt_xml.ml
+++ b/output/create_libvirt_xml.ml
@@ -312,18 +312,26 @@ let create_libvirt_xml ?pool source inspect
(* The devices. *)
let devices = ref [] in
+ (* This will affect all of the virtio devices (if any). *)
+ let virtio_transitional =
+ guestcaps.gcaps_machine = Q35 && not guestcaps.gcaps_virtio_1_0 in
+ let virtio_model =
+ if virtio_transitional then "virtio-transitional" else "virtio"
in
+
(* Fixed and removable disks. *)
let () =
- let make_disk bus_name drive_prefix i = function
+ let make_disk bus_name ?(viotrans = false) drive_prefix i = function
| BusSlotEmpty -> Comment (sprintf "%s slot %d is empty" bus_name i)
| BusSlotDisk d ->
let outdisk = outdisk_name d.s_disk_id in
- e "disk" [
- "type", if pool = None then "file" else
"volume";
- "device", "disk"
- ] [
+ e "disk" (
+ [
+ "type", if pool = None then "file" else
"volume";
+ "device", "disk"
+ ] @ if (viotrans) then [ "model", "virtio-transitional" ]
else []
+ ) [
e "driver" [
"name", "qemu";
"type", output_format;
@@ -364,7 +372,7 @@ let create_libvirt_xml ?pool source inspect
in
List.push_back_list devices
- (List.mapi (make_disk "virtio" "vd")
+ (List.mapi (make_disk "virtio" ~viotrans:virtio_transitional
"vd")
(Array.to_list target_buses.target_virtio_blk_bus));
let ide_disks =
match guestcaps.gcaps_machine with
@@ -392,7 +400,7 @@ let create_libvirt_xml ?pool source inspect
let nics =
let net_model =
match guestcaps.gcaps_net_bus with
- | Virtio_net -> "virtio" | E1000 -> "e1000" | RTL8139
-> "rtl8139" in
+ | Virtio_net -> virtio_model | E1000 -> "e1000" | RTL8139 ->
"rtl8139" in
List.map (
fun { s_mac = mac; s_vnet_type = vnet_type; s_vnet = vnet } ->
let vnet_type_str =
@@ -483,7 +491,7 @@ let create_libvirt_xml ?pool source inspect
(* Miscellaneous KVM devices. *)
if guestcaps.gcaps_virtio_rng then
List.push_back devices (
- e "rng" ["model", "virtio"] [
+ e "rng" ["model", virtio_model] [
(* XXX Using /dev/urandom requires libvirt >= 1.3.4. Libvirt
* was broken before that.
*)
@@ -496,7 +504,7 @@ let create_libvirt_xml ?pool source inspect
List.push_back devices (
e "memballoon"
["model",
- if guestcaps.gcaps_virtio_balloon then "virtio" else "none"]
+ if guestcaps.gcaps_virtio_balloon then virtio_model else "none"]
[]
);
if guestcaps.gcaps_isa_pvpanic then
@@ -508,7 +516,7 @@ let create_libvirt_xml ?pool source inspect
List.push_back devices (
e "viosock"
["model",
- if guestcaps.gcaps_virtio_socket then "virtio" else "none"]
+ if guestcaps.gcaps_virtio_socket then virtio_model else "none"]
[]
);
--
2.19.1.3.g30247aa5d201