From 91ff7bf3e20ced8742319d77bd5f2b9929bc3c24 Mon Sep 17 00:00:00 2001

From: Paolo Bonzini <pbonzini@redhat.com>

Date: Fri, 20 Sep 2013 16:58:00 +0200

Subject: [PATCH] virtio-pci: add device_unplugged callback

This fixes a crash in hot-unplug of virtio-pci devices behind a PCIe

switch.  The crash happens because the ioeventfd is still set whent the

child is destroyed (destruction happens in postorder).  Then the proxy

tries to unset to ioeventfd, but the virtqueue structure that holds the

EventNotifier has been trashed in the meanwhile.  kvm_set_ioeventfd_pio

does not expect failure and aborts.

The fix is simply to move parts of uninitialization to a new

device_unplugged callback, which is called before the child is destroyed.

Cc: qemu-stable@nongnu.org

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

---

 hw/virtio/virtio-pci.c | 12 ++++++++++--

 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/hw/virtio/virtio-pci.c b/hw/virtio/virtio-pci.c

index be18e92..1a363ca 100644

--- a/hw/virtio/virtio-pci.c

+++ b/hw/virtio/virtio-pci.c

@@ -1001,6 +1001,15 @@ static void virtio_pci_device_plugged(DeviceState *d)

                                                       proxy->host_features);

 }

+static void virtio_pci_device_unplugged(DeviceState *d)

+{

+    PCIDevice *pci_dev = PCI_DEVICE(d);

+    VirtIOPCIProxy *proxy = VIRTIO_PCI(d);

+

+    virtio_pci_stop_ioeventfd(proxy);

+    msix_uninit_exclusive_bar(pci_dev);

+}

+

 static int virtio_pci_init(PCIDevice *pci_dev)

 {

     VirtIOPCIProxy *dev = VIRTIO_PCI(pci_dev);

@@ -1015,9 +1024,7 @@ static int virtio_pci_init(PCIDevice *pci_dev)

 static void virtio_pci_exit(PCIDevice *pci_dev)

 {

     VirtIOPCIProxy *proxy = VIRTIO_PCI(pci_dev);

-    virtio_pci_stop_ioeventfd(proxy);

     memory_region_destroy(&proxy->bar);

-    msix_uninit_exclusive_bar(pci_dev);

 }

 static void virtio_pci_reset(DeviceState *qdev)

@@ -1552,6 +1559,7 @@ static void virtio_pci_bus_class_init(ObjectClass *klass, void *data)

     k->set_guest_notifiers = virtio_pci_set_guest_notifiers;

     k->vmstate_change = virtio_pci_vmstate_change;

     k->device_plugged = virtio_pci_device_plugged;

+    k->device_unplugged = virtio_pci_device_unplugged;

 }

 static const TypeInfo virtio_pci_bus_info = {