Re: [Xen-devel] debian stretch dom0 + xen 4.9 fails to boot

[Paul Durrant <Paul.Durrant@xxxxxxxxxx>]

> -----Original Message-----
> From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
> Sent: 07 June 2017 13:00
> To: Paul Durrant <Paul.Durrant@xxxxxxxxxx>
> Cc: Julien Grall (julien.grall@xxxxxxx) <julien.grall@xxxxxxx>; Andrew
> Cooper <Andrew.Cooper3@xxxxxxxxxx>; xen-devel(xen-
> devel@xxxxxxxxxxxxxxxxxxxx) <xen-devel@xxxxxxxxxxxxxxxxxxxx>;
> 'BorisOstrovsky' <boris.ostrovsky@xxxxxxxxxx>; Juergen Gross
> <jgross@xxxxxxxx>
> Subject: RE: [Xen-devel] debian stretch dom0 + xen 4.9 fails to boot
> 
> >>> On 07.06.17 at 13:55, <Paul.Durrant@xxxxxxxxxx> wrote:
> >> From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
> >> Sent: 07 June 2017 12:50
> >> 2) Provide the E820 map of that box.
> >> I'm suspecting the BIOS might use an EBDA without recording it in
> >> the low BIOS data area. If it's reported in E820 that would then
> >> likely be the final kick for us to obey to the E820 map when
> >> determining where to put the trampoline.
> >>
> >
> > The stretch kernel booted bare-metal reports:
> >
> > [    0.000000] e820: BIOS-provided physical RAM map:
> > [    0.000000] BIOS-e820: [mem 0x0000000000000000-0x00000000000963ff]
> usable
> > [    0.000000] BIOS-e820: [mem 0x0000000000096400-0x000000000009ffff]
> reserved
> 
> There we go. Subtracting 4k may then even be too little (depending
> what EBDA and low memory values the system reports). Of course
> it would be a BIOS bug if they reported some memory they use for
> themselves through only E820, as that interface is not required to
> be present, and really, really old software wouldn't even know
> about it and would hence also be in trouble.
> 

Neither 4k nor 8k seemed to be enough. Even subtracting another 64k doesn't 
work. I guess I'm going to have to try to write some code to log values to the 
VGA buffer to see what is going on.

  Paul


> Jan


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