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

[Wei Liu <wei.liu2@citrix.com>]

On Tue, Oct 18, 2016 at 12:09:55PM -0700, Stefano Stabellini wrote:
> 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.
> 

Actually it was introduced in 4.7.

> ---
> 
> 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 <sstabellini@kernel.org>
> 
> 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>


Can we just change the macro to

  #define USB_CONN_RING_SIZE(pg_size) __CONST_RING_SIZE(usbif_conn, (pg_size)

?

I also found a similar issue in vscsiif.h.

Wei.


>  
>  /*