Re: kdump with xen-unstable on efi machine

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Wed, Nov 26, 2014 at 03:01:51PM +0100, Juergen Gross wrote:
> On 11/26/2014 01:41 PM, Andrew Cooper wrote:
> >On 26/11/14 12:15, Juergen Gross wrote:
> >>Hi,
> >>
> >>I tried to enable kdump on my test-machine with actual xen-unstable
> >>booting via EFI.
> >>
> >>The kdump kernel is not being loaded.
> >>
> >>I'm seeing the memory being reserved:
> >>
> >>(XEN) EFI RAM map:
> >>(XEN)  0000000000000000 - 00000000000a0000 (usable)
> >>(XEN)  0000000000100000 - 000000004bc00000 (usable)
> >>(XEN)  000000004bc00000 - 000000005bc00000 (reserved)
> >>(XEN)  000000005bc00000 - 000000005bfec000 (usable)
> >>(XEN)  000000005bfec000 - 000000005c000000 (ACPI NVS)
> >>(XEN)  000000005c000000 - 000000006a429000 (usable)
> >>(XEN)  000000006a429000 - 000000006a42c000 (reserved)
> >>(XEN)  000000006a42c000 - 000000006a7a2000 (usable)
> >>(XEN)  000000006a7a2000 - 000000006a7a8000 (reserved)
> >>(XEN)  000000006a7a8000 - 000000006a987000 (usable)
> >>(XEN)  000000006a987000 - 000000006a98d000 (reserved)
> >>(XEN)  000000006a98d000 - 000000006aa63000 (usable)
> >>(XEN)  000000006aa63000 - 000000006aa73000 (reserved)
> >>(XEN)  000000006aa73000 - 000000006ac60000 (usable)
> >>(XEN)  000000006ac60000 - 000000006ac61000 (reserved)
> >>(XEN)  000000006ac61000 - 000000006ac9b000 (ACPI data)
> >>(XEN)  000000006ac9b000 - 000000006acac000 (reserved)
> >>(XEN)  000000006acac000 - 000000006acad000 (usable)
> >>(XEN)  000000006acad000 - 000000006acae000 (reserved)
> >>(XEN)  000000006acae000 - 000000007189c000 (usable)
> >>(XEN)  000000007189c000 - 0000000071946000 (reserved)
> >>(XEN)  0000000071946000 - 0000000072d76000 (ACPI NVS)
> >>(XEN)  0000000072d76000 - 0000000072db2000 (ACPI data)
> >>(XEN)  0000000072db2000 - 0000000072edc000 (usable)
> >>(XEN)  0000000080000000 - 0000000090000000 (reserved)
> >>(XEN)  0000000100000000 - 0000002080000000 (usable)
> >>(XEN) Kdump: 256MB (262144kB) at 0x206dff4000
> >>
> >>I'd expect this area being visible in the efi or e820 map presented to
> >>dom0, but I can't see anything:
> >
> >This is expected.  The dom0 kernel now has nothing at all do with
> >loading crash kernel.  Loading happens via hypercalls straight from the
> >kexec utility.
> >
> >You need kexec-tools 2.0.4 (I think) or later, compiled with Xen
> >support, but it should JustWork.
> 
> Should. I have kexec 2.0.5 with Xen support. Doesn't work:
> 
> Excerpt form strace:
> 
> "sysctl operation failed -- need to rebuild the user-space tool set?\n"
> 
> My personal translation: kexec is tightly coupled to the Xen version
> (this one was built against Xen 4.4.1 AFAIK).

Odd, the hypercall interface did not change in Xen 4.5 for kexec?

Perhaps it is making some other hypercalls that are tied in
to the version of Xen (like sysctl ones?).

I presume with recompiling it works?
> 
> Perhaps we should add kexec to the tools directory?

Gosh no.
> 
> 
> Juergen
> 
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