[Qemu-devel] [PATCH] xen-usb.c/usbif.h: fix ARM64 build issue

[Stefano Stabellini]

Hi all,

While I was investigating the recent libxl ARM64 build issue, I found
another ARM64 build problem. This one is in QEMU:


  CC    hw/usb/xen-usb.o
hw/usb/xen-usb.c: In function ‘usbback_gnttab_map’:
hw/usb/xen-usb.c:163:56: error: ‘PAGE_SIZE’ undeclared (first use in this 
function)
             (unsigned)usbback_req->req.seg[i].length > PAGE_SIZE) {
                                                        ^
hw/usb/xen-usb.c:163:56: note: each undeclared identifier is reported only once 
for each function it appears in
In file included from hw/usb/xen-usb.c:36:0:
hw/usb/xen-usb.c: In function ‘usbback_alloc’:
/users/stefanos/xen/tools/../tools/include/xen/io/usbif.h:229:56: error: 
‘PAGE_SIZE’ undeclared (first use in this function)
 #define USB_URB_RING_SIZE __CONST_RING_SIZE(usbif_urb, PAGE_SIZE)
                                                        ^
/users/stefanos/xen/tools/../tools/include/xen/io/ring.h:45:23: note: in 
definition of macro ‘__RD32’
 #define __RD32(_x) (((_x) & 0xffff0000) ? __RD16((_x)>>16)<<16 : __RD16(_x))
                       ^
/users/stefanos/xen/tools/../tools/include/xen/io/usbif.h:229:27: note: in 
expansion of macro ‘__CONST_RING_SIZE’
 #define USB_URB_RING_SIZE __CONST_RING_SIZE(usbif_urb, PAGE_SIZE)
                           ^
hw/usb/xen-usb.c:1029:51: note: in expansion of macro ‘USB_URB_RING_SIZE’
     max_grants = USBIF_MAX_SEGMENTS_PER_REQUEST * USB_URB_RING_SIZE + 2;
                                                   ^
make: *** [hw/usb/xen-usb.o] Error 1


It is caused by PAGE_SIZE being utilized in
xen/include/public/io/usbif.h, but undefined on ARM64 (in userspace).
QEMU includes xen/include/public/io/usbif.h directly, therefore
hw/usb/xen-usb.c doesn't build.

I don't think we should be using "PAGE_SIZE" in public/io/usbif.h, but
that file is present in too many Xen releases to ignore now. So I am
going to work around the issue in QEMU.

---

xen-usb.c does not build on ARM64 because it includes xen/io/usbif.h
which uses PAGE_SIZE without defining it. The header file has been
shipped with too many Xen releases to be able to solve the problem at
the source.

This patch define PAGE_SIZE as XC_PAGE_SIZE when undefined.

Signed-off-by: Stefano Stabellini <address@hidden>

diff --git a/hw/usb/xen-usb.c b/hw/usb/xen-usb.c
index 174d715..ca9df87 100644
--- a/hw/usb/xen-usb.c
+++ b/hw/usb/xen-usb.c
@@ -34,6 +34,11 @@
 #include "qapi/qmp/qstring.h"
 
 #include <xen/io/ring.h>
+
+/* xen/io/usbif.h references PAGE_SIZE without defining it */
+#ifndef PAGE_SIZE
+#define PAGE_SIZE XC_PAGE_SIZE
+#endif
 #include <xen/io/usbif.h>
 
 /*