[Qemu-trivial] [PATCH v3] hw/usb/hcd-xhci: Fix GCC 9 build warning

[Alistair Francis]

Fix this build warning with GCC 9 on Fedora 30:
hw/usb/hcd-xhci.c:3339:66: error: ‘%d’ directive output may be truncated 
writing between 1 and 10 bytes into a region of size 5 
[-Werror=format-truncation=]
 3339 |             snprintf(port->name, sizeof(port->name), "usb2 port #%d", 
i+1);
      |                                                                  ^~
hw/usb/hcd-xhci.c:3339:54: note: directive argument in the range [1, 2147483647]
 3339 |             snprintf(port->name, sizeof(port->name), "usb2 port #%d", 
i+1);
      |                                                      ^~~~~~~~~~~~~~~
In file included from /usr/include/stdio.h:867,
                 from /home/alistair/qemu/include/qemu/osdep.h:99,
                 from hw/usb/hcd-xhci.c:21:
/usr/include/bits/stdio2.h:67:10: note: ‘__builtin___snprintf_chk’ output 
between 13 and 22 bytes into a destination of size 16
   67 |   return __builtin___snprintf_chk (__s, __n, __USE_FORTIFY_LEVEL - 1,
      |          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
   68 |        __bos (__s), __fmt, __va_arg_pack ());
      |        ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Signed-off-by: Alistair Francis <address@hidden>
Reviewed-by: Laurent Vivier <address@hidden>
Reviewed-by: Daniel P. Berrangé <address@hidden>
Reviewed-by: Philippe Mathieu-Daudé <address@hidden>
---
This is the onl patch left if my original series "Fix some GCC 9 build
warnings" that hasn't either been accepeted into a maintainers tree or
fixed by someone else.

 hw/usb/hcd-xhci.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/hw/usb/hcd-xhci.c b/hw/usb/hcd-xhci.c
index ec28bee319..a15b103b65 100644
--- a/hw/usb/hcd-xhci.c
+++ b/hw/usb/hcd-xhci.c
@@ -3321,6 +3321,8 @@ static void usb_xhci_init(XHCIState *xhci)
 
     usb_bus_new(&xhci->bus, sizeof(xhci->bus), &xhci_bus_ops, dev);
 
+    g_assert(usbports <= MAX(MAXPORTS_2, MAXPORTS_3));
+
     for (i = 0; i < usbports; i++) {
         speedmask = 0;
         if (i < xhci->numports_2) {
-- 
2.21.0