Re: [Qemu-devel] [PATCH] xhci: child detach fix

[Gonglei (Arei)]

> -----Original Message-----
> From: address@hidden
> [mailto:address@hidden On
> Behalf Of Gerd Hoffmann
> Sent: Monday, May 12, 2014 8:50 PM
> To: address@hidden
> Cc: Gerd Hoffmann
> Subject: [Qemu-devel] [PATCH] xhci: child detach fix
> 
> xhci_child_detach() zaps the wrong slot when unplugging a device
> connected via usb-hub:  Instead of the device's slot the slot of the
> usb-hub is used.  Fix it.
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=1075846
> 
> Signed-off-by: Gerd Hoffmann <address@hidden>
> ---
>  hw/usb/hcd-xhci.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
> index ef3177a..6753a42 100644
> --- a/hw/usb/hcd-xhci.c
> +++ b/hw/usb/hcd-xhci.c
> @@ -3435,7 +3435,7 @@ static void xhci_child_detach(USBPort *uport,
> USBDevice *child)
>      USBBus *bus = usb_bus_from_device(child);
>      XHCIState *xhci = container_of(bus, XHCIState, bus);
> 
> -    xhci_detach_slot(xhci, uport);
> +    xhci_detach_slot(xhci, child->port);
>  }
> 
>  static USBPortOps xhci_uport_ops = {
> --
> 1.8.3.1
> 
Reviewed-by: Gonglei <address@hidden>

BTW, in usb_release_port(), the detached port should be insert
the head of bus->free list table. Because of the save/restore will
cause qemu crash, after hot plug/hot unplug multi times. For example,
save the port '2' to memory file, but when we restore it, the port will
be assign to '1' over again, which not match with the memory file,
and then crash qemu.

The error log:

"Unknown savevm section or instance '0000:00:04.0/3/usb-host' 2"

The below patch can solve this problem.

Signed-off-by: Gonglei <address@hidden>
---
 hw/usb/bus.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/hw/usb/bus.c b/hw/usb/bus.c
index e48b19f..4e6ccad 100644
--- a/hw/usb/bus.c
+++ b/hw/usb/bus.c
@@ -442,7 +442,7 @@ void usb_release_port(USBDevice *dev)
     dev->port = NULL;
     port->dev = NULL;
 
-    QTAILQ_INSERT_TAIL(&bus->free, port, next);
+    QTAILQ_INSERT_HEAD(&bus->free, port, next);
     bus->nfree++;
 }
 
-- 
1.7.12.4


Best regards,
-Gonglei