Re: [Xen-devel] [RFC PATCH] xen/x86: Increase xen_e820_map to E820_X_MAX possible entries

[Alex Thorlton <athorlton@xxxxxxx>]

On Wed, Nov 16, 2016 at 05:42:11PM +0100, Juergen Gross wrote:
> On 15/11/16 08:15, Jan Beulich wrote:
> >>>> On 15.11.16 at 07:33, <JGross@xxxxxxxx> wrote:
> >> On 15/11/16 01:11, Alex Thorlton wrote:
> >>> Hey everyone,
> >>>
> >>> We're having problems with large systems hitting a BUG in
> >>> xen_memory_setup, due to extra e820 entries created in the
> >>> XENMEM_machine_memory_map callback.  The change in the patch gets things
> >>> working, but Boris and I wanted to get opinions on whether or not this
> >>> is the appropriate/entire solution, which is why I've sent it as an RFC
> >>> for now.
> 
> >> While I think extending the e820 table is the right thing to do I'm
> >> questioning the assumptions here.
> >>
> >> Looking briefly through the Xen hypervisor sources I think it isn't
> >> yet ready for such large machines: the hypervisor's e820 map seems to
> >> be still limited to 128 e820 entries. Jan, did I overlook an EFI
> >> specific path extending this limitation?
> > 
> > No, you didn't. I do question the correlation with "large machines"
> > here though: The issue isn't with large machines afaict, but with
> > ones having very many entries (i.e. heavily fragmented).
> 
> Alex, I would appreciate if you could send me the E820 map printed
> at a bare metal Linux boot. I suspect it is already larger than
> 128 entries and the hypervisor is just cutting it off at the end.

No problem!  I'll get this to you today.

- Alex

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxx
https://lists.xen.org/xen-devel