Re: [Qemu-devel] [PATCH] xen: net backend doesn't need linux headers.

[Blue Swirl <blauwirbel@gmail.com>]

On 6/6/09, Andreas Färber <andreas.faerber@web.de> wrote:
>
>  Am 06.06.2009 um 21:43 schrieb Andreas Färber:
>
>
>
> >
> > Am 06.06.2009 um 17:52 schrieb Blue Swirl:
> >
> >
> > > On 6/2/09, Gerd Hoffmann <kraxel@redhat.com> wrote:
> > >
> > > > Drop them to make qemu build on OpenSolaris.
> > > >
> > > > Cc: Andreas Färber <andreas.faerber@web.de>
> > > > Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
> > > >
> > >
> > > Thanks, applied.
> > >
> >
> > Thanks, the patch helps, but doesn't fully fix the build:
> >
> >  CC    xen_backend.o
> >  CC    xen_devconfig.o
> >  CC    xen_console.o
> >  CC    xenfb.o
> >  CC    xen_disk.o
> > In file included from
> /export/home/andreas/QEMU/qemu/hw/xen_disk.c:43:
> > /export/home/andreas/QEMU/qemu/hw/xen_blkif.h:20:
> warning: #pragma pack(push[, id], <n>) is not supported on this target
> > /export/home/andreas/QEMU/qemu/hw/xen_blkif.h:36:
> warning: #pragma pack(pop[, id], <n>) is not supported on this target
> >  CC    xen_nic.o
> > /export/home/andreas/QEMU/qemu/hw/xen_nic.c: In function
> `net_tx_packets':
> > /export/home/andreas/QEMU/qemu/hw/xen_nic.c:179: error:
> `PAGE_SIZE' undeclared (first use in this function)
> > /export/home/andreas/QEMU/qemu/hw/xen_nic.c:179: error:
> (Each undeclared identifier is reported only once
> > /export/home/andreas/QEMU/qemu/hw/xen_nic.c:179: error:
> for each function it appears in.)
> > make: *** [xen_nic.o] Error 1
> >
> > A quick search for PAGE_SIZE revealed some posts saying that PAGE_SIZE
> shouldn't be used in userland and be replaced with getpagesize(). Looking at
> the code though I see a number of XC_PAGE_SIZE that don't result in errors.
> Might PAGE_SIZE be a typo then?
> >
>
>  With this patch xen_nic.c compiles:
>
>  diff --git a/hw/xen_nic.c b/hw/xen_nic.c
>  index 048d865..3615c8c 100644
>  --- a/hw/xen_nic.c
>  +++ b/hw/xen_nic.c
>  @@ -176,7 +176,7 @@ static void net_tx_packets(struct XenNetDev *netdev)
>             if (txreq.flags & NETTXF_csum_blank) {
>                 /* have read-only mapping -> can't fill checksum in-place */
>                 if (!tmpbuf)
>  -                    tmpbuf = malloc(PAGE_SIZE);
>  +                    tmpbuf = malloc(XC_PAGE_SIZE);
>                 memcpy(tmpbuf, page + txreq.offset, txreq.size);
>                 net_checksum_calculate(tmpbuf, txreq.size);
>                 qemu_send_packet(netdev->vs, tmpbuf, txreq.size);

It also looks like there is no real need for using host or target page
size, so we could use for example MIN(4096,  txreq.size).

>  If then goes on to compile Xen stuff into sparc-softmmu and fails:
>
>   CC    sparc-softmmu/xen_machine_pv.o
>  /export/home/andreas/QEMU/qemu/hw/xen_machine_pv.c:116:
> warning: initialization from incompatible pointer type
>   CC    sparc-softmmu/xen_domainbuild.o
>  [...]
>   LINK  sparc-softmmu/qemu-system-sparc
>  Undefined            first referenced
>   symbol                  in file
>  xc_gnttab_map_grant_refs
> ../libqemu_common.a(xen_disk.o)
>  xc_gnttab_map_grant_ref
> ../libqemu_common.a(xen_disk.o)
>  xc_gnttab_munmap
> ../libqemu_common.a(xen_disk.o)
>  xc_gnttab_open
> ../libqemu_common.a(xen_backend.o)
>  ld: fatal: symbol referencing errors. No output written to
> qemu-system-sparc
>  collect2: ld returned 1 exit status
>  gmake[1]: *** [qemu-system-sparc] Error 1
>  make: *** [subdir-sparc-softmmu] Error 2
>
>  Same errors when linking i386-softmmu.
>
>  OpenSolaris 2009.06 has SUNWxvm@3.1,5.11-111, I interpret this as being Xen
> 3.1 - is that maybe too old?
>  Perhaps it's easier to just have QEMU's configure disable Xen support on
> Solaris for now then?

configure should probe for xc_gnttab symbols and disable Xen if these
are not found.