[Qemu-devel] [PULL 13/13] ehci: fix segfault when hot-unplugging ehci controller

[Gerd Hoffmann <kraxel@redhat.com>]

From: Gonglei <arei.gonglei@huawei.com>

When hot-unplugging the usb controllers (ehci/uhci),
we have to clean all resouce of these devices,
involved registered reset handler. Otherwise, it
may cause NULL pointer access and/or segmentation fault
if we reboot the guest os after hot-unplugging.

Let's hook up reset via DeviceClass->reset() and drop
the qemu_register_reset() call. Then Qemu will register
and unregister the reset handler automatically.

Cc: qemu-stable <qemu-stable@nongnu.org>
Reported-by: Lidonglin <lidonglin@huawei.com>
Signed-off-by: Gonglei <arei.gonglei@huawei.com>
---
 hw/usb/hcd-ehci-pci.c    | 10 ++++++++++
 hw/usb/hcd-ehci-sysbus.c | 10 ++++++++++
 hw/usb/hcd-ehci.c        |  3 +--
 hw/usb/hcd-ehci.h        |  1 +
 4 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/hw/usb/hcd-ehci-pci.c b/hw/usb/hcd-ehci-pci.c
index 4c80707..7afa5f9 100644
--- a/hw/usb/hcd-ehci-pci.c
+++ b/hw/usb/hcd-ehci-pci.c
@@ -101,6 +101,15 @@ static void usb_ehci_pci_exit(PCIDevice *dev)
     }
 }
 
+static void usb_ehci_pci_reset(DeviceState *dev)
+{
+    PCIDevice *pci_dev = PCI_DEVICE(dev);
+    EHCIPCIState *i = PCI_EHCI(pci_dev);
+    EHCIState *s = &i->ehci;
+
+    ehci_reset(s);
+}
+
 static void usb_ehci_pci_write_config(PCIDevice *dev, uint32_t addr,
                                       uint32_t val, int l)
 {
@@ -143,6 +152,7 @@ static void ehci_class_init(ObjectClass *klass, void *data)
     k->config_write = usb_ehci_pci_write_config;
     dc->vmsd = &vmstate_ehci_pci;
     dc->props = ehci_pci_properties;
+    dc->reset = usb_ehci_pci_reset;
 }
 
 static const TypeInfo ehci_pci_type_info = {
diff --git a/hw/usb/hcd-ehci-sysbus.c b/hw/usb/hcd-ehci-sysbus.c
index 19ed2c2..cd1cc14 100644
--- a/hw/usb/hcd-ehci-sysbus.c
+++ b/hw/usb/hcd-ehci-sysbus.c
@@ -42,6 +42,15 @@ static void usb_ehci_sysbus_realize(DeviceState *dev, Error **errp)
     sysbus_init_irq(d, &s->irq);
 }
 
+static void usb_ehci_sysbus_reset(DeviceState *dev)
+{
+    SysBusDevice *d = SYS_BUS_DEVICE(dev);
+    EHCISysBusState *i = SYS_BUS_EHCI(d);
+    EHCIState *s = &i->ehci;
+
+    ehci_reset(s);
+}
+
 static void ehci_sysbus_init(Object *obj)
 {
     SysBusDevice *d = SYS_BUS_DEVICE(obj);
@@ -70,6 +79,7 @@ static void ehci_sysbus_class_init(ObjectClass *klass, void *data)
     dc->realize = usb_ehci_sysbus_realize;
     dc->vmsd = &vmstate_ehci_sysbus;
     dc->props = ehci_sysbus_properties;
+    dc->reset = usb_ehci_sysbus_reset;
     set_bit(DEVICE_CATEGORY_USB, dc->categories);
 }
 
diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
index 5c2a452..d4d7547 100644
--- a/hw/usb/hcd-ehci.c
+++ b/hw/usb/hcd-ehci.c
@@ -839,7 +839,7 @@ static USBDevice *ehci_find_device(EHCIState *ehci, uint8_t addr)
 }
 
 /* 4.1 host controller initialization */
-static void ehci_reset(void *opaque)
+void ehci_reset(void *opaque)
 {
     EHCIState *s = opaque;
     int i;
@@ -2465,7 +2465,6 @@ void usb_ehci_realize(EHCIState *s, DeviceState *dev, Error **errp)
     s->async_bh = qemu_bh_new(ehci_frame_timer, s);
     s->device = dev;
 
-    qemu_register_reset(ehci_reset, s);
     s->vmstate = qemu_add_vm_change_state_handler(usb_ehci_vm_state_change, s);
 }
 
diff --git a/hw/usb/hcd-ehci.h b/hw/usb/hcd-ehci.h
index 2bc259c..87b240f 100644
--- a/hw/usb/hcd-ehci.h
+++ b/hw/usb/hcd-ehci.h
@@ -325,6 +325,7 @@ extern const VMStateDescription vmstate_ehci;
 void usb_ehci_init(EHCIState *s, DeviceState *dev);
 void usb_ehci_realize(EHCIState *s, DeviceState *dev, Error **errp);
 void usb_ehci_unrealize(EHCIState *s, DeviceState *dev, Error **errp);
+void ehci_reset(void *opaque);
 
 #define TYPE_PCI_EHCI "pci-ehci-usb"
 #define PCI_EHCI(obj) OBJECT_CHECK(EHCIPCIState, (obj), TYPE_PCI_EHCI)
-- 
1.8.3.1