Re: [XenPPC] boot failure with large dom0

[Hollis Blanchard <hollisb@xxxxxxxxxx>]

If the problem were that dom0 was only partially transferred, we would
see dom0 start to boot and fail. The boot_of_alloc_init message happens
way before that point.

The early boot code only tracks the first 32M of memory, and I believe
that is the problem here: we're overflowing the bitmap we're using to
track memory. Page 2000 is address 2000000 (32MB). Try this patch:

diff -r 20e5f508accc xen/arch/powerpc/boot_of.c
--- a/xen/arch/powerpc/boot_of.c        Tue Feb 06 13:42:19 2007 -0600
+++ b/xen/arch/powerpc/boot_of.c        Wed Feb 07 16:38:24 2007 -0600
@@ -394,6 +394,9 @@ static void boot_of_alloc_init(int m, ui
     u64 start;
     u64 size;
 
+    if (((ulong)_end >> PAGE_SHIFT) >= MEM_AVAILABLE_PAGES)
+        of_panic("image is too big");
+
     rc = of_getprop(m, "available", a, sizeof (a));
     if (rc > 0) {
         int l =  rc / sizeof(a[0]);

-- 
Hollis Blanchard
IBM Linux Technology Center

On Wed, 2007-02-07 at 16:20 -0600, Jerone Young wrote:
> So it looks like the problem has to do with tftp which apears to have a
> 64MB send limit. The file is over this and so everything does not make
> it. Adding a check for dom0 image size does not good since the image
> itself is not fully transfered. Which make since why you get the error:
> boot_of_alloc_init: pg :0x2000 of our image is different
> at bootup.
> 
> On Wed, 2007-02-07 at 11:59 -0600, Hollis Blanchard wrote:
> > I use a vmlinux as dom0, but it's a stripped vmlinux. A vmlinux with
> > full debug symbols is 55MB here, which probably explains this problem.
> > 
> > Could you see how easy it would be to catch this problem at runtime and
> > have a nice panic? Checking dom0_len in __start_xen() would probably do
> > the trick, maybe something like:
> >         if (dom0_start + dom0_len > (32<<20))
> >                 panic("dom0 is too big");
> > 
> 
> 
> _______________________________________________
> Xen-ppc-devel mailing list
> Xen-ppc-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-ppc-devel


_______________________________________________
Xen-ppc-devel mailing list
Xen-ppc-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-ppc-devel