[QEMU][PATCHv2 1/8] xen: when unplugging emulated devices skip virtio devices

[Vikram Garhwal <vikram.garhwal@xxxxxxx>]

From: Juergen Gross <jgross@xxxxxxxx>

Virtio devices should never be unplugged at boot time, as they are
similar to pci passthrough devices.

Signed-off-by: Juergen Gross <jgross@xxxxxxxx>
Signed-off-by: Vikram Garhwal <vikram.garhwal@xxxxxxx>
---
 docs/system/i386/xen.rst   |  3 ---
 hw/i386/xen/xen_platform.c | 10 ++++++++--
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/docs/system/i386/xen.rst b/docs/system/i386/xen.rst
index f06765e88c..b86d57af6e 100644
--- a/docs/system/i386/xen.rst
+++ b/docs/system/i386/xen.rst
@@ -52,9 +52,6 @@ It is necessary to use the pc machine type, as the q35 
machine uses AHCI instead
 of legacy IDE, and AHCI disks are not unplugged through the Xen PV unplug
 mechanism.
 
-VirtIO devices can also be used; Linux guests may need to be dissuaded from
-umplugging them by adding 'xen_emul_unplug=never' on their command line.
-
 Properties
 ----------
 
diff --git a/hw/i386/xen/xen_platform.c b/hw/i386/xen/xen_platform.c
index 17457ff3de..0187b73eeb 100644
--- a/hw/i386/xen/xen_platform.c
+++ b/hw/i386/xen/xen_platform.c
@@ -28,6 +28,7 @@
 #include "hw/ide/pci.h"
 #include "hw/pci/pci.h"
 #include "migration/vmstate.h"
+#include "hw/virtio/virtio-bus.h"
 #include "net/net.h"
 #include "trace.h"
 #include "sysemu/xen.h"
@@ -129,10 +130,11 @@ static bool pci_device_is_passthrough(PCIDevice *d)
 
 static void unplug_nic(PCIBus *b, PCIDevice *d, void *o)
 {
-    /* We have to ignore passthrough devices */
+    /* We have to ignore passthrough devices  and virtio devices. */
     if (pci_get_word(d->config + PCI_CLASS_DEVICE) ==
             PCI_CLASS_NETWORK_ETHERNET
-            && !pci_device_is_passthrough(d)) {
+            && !pci_device_is_passthrough(d)
+            && !qdev_get_child_bus(&d->qdev, TYPE_VIRTIO_BUS)) {
         object_unparent(OBJECT(d));
     }
 }
@@ -208,6 +210,10 @@ static void unplug_disks(PCIBus *b, PCIDevice *d, void 
*opaque)
     /* We have to ignore passthrough devices */
     if (pci_device_is_passthrough(d))
         return;
+    /* Ignore virtio devices */
+    if (qdev_get_child_bus(&d->qdev, TYPE_VIRTIO_BUS)) {
+        return;
+    }
 
     switch (pci_get_word(d->config + PCI_CLASS_DEVICE)) {
     case PCI_CLASS_STORAGE_IDE:
-- 
2.17.1