Re: [Xen-devel] Crash on boot with 2.6.37-rc8-git3

[M A Young <m.a.young@xxxxxxxxxxxx>]

On Tue, 25 Jan 2011, Stefano Stabellini wrote:

> I think you need the slightly improved version I posted before that can
> handle map[i].addr not page aligned (I silently added a s-o-b Young, I
> hope he's OK with this).
Yes and yes. My version doesn't work if map[i].addr is not page aligned. 
The aim is to make sure the end address is page aligned, and avoid ending 
with a partial page which won't have a PFN and might also require 
different treatment if there is reserved content in the rest of the page 
(which is true in my case).
        Michael Young

> commit b84683ad1e704c2a296d08ff0cbe29db936f94a7
> Author: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
> Date:   Tue Jan 25 12:03:42 2011 +0000
>
>    xen: make sure the e820 memory regions end at page boundary
>
>    Signed-off-by: M A Young <m.a.young@xxxxxxxxxxxx>
>    Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
>
> diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
> index b5a7f92..a3d28a1 100644
> --- a/arch/x86/xen/setup.c
> +++ b/arch/x86/xen/setup.c
> @@ -179,7 +179,10 @@ char * __init xen_memory_setup(void)
>         e820.nr_map = 0;
>         xen_extra_mem_start = mem_end;
>         for (i = 0; i < memmap.nr_entries; i++) {
> -               unsigned long long end = map[i].addr + map[i].size;
> +               unsigned long long end;
> +               if (map[i].type == E820_RAM)
> +                       map[i].size -= (map[i].size + map[i].addr) % PAGE_SIZE;
> +               end = map[i].addr + map[i].size;
>
>                 if (map[i].type == E820_RAM && end > mem_end) {
>                         /* RAM off the end - may be partially included */
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