Re: [PATCH] kexec/kdump implementation for Xen PV domU

Re: [PATCH] kexec/kdump implementation for Xen PV domU

[Greg KH]

On Mon, Jul 29, 2013 at 07:15:43PM +0200, Daniel Kiper wrote:
> Hi all,
> 
> Here I am sending as attachments patches enabling kexec/kdump
> support in Xen PV domU. Only x84_64 architecture is supported.
> There is no support for i386 but some code could be easily reused.
> Here is a description of patches:
>   - kexec-tools-2.0.3_20120522.patch: patch for kexec-tools
>     which cleanly applies to version 2.0.3,
>   - kexec-kernel-only_20120522.patch: main kexec/kdump kernel patch;
>     it was prepared for quite old custom version of Xen Linux Kernel 2.6.18;
>     it should apply to publicly available Xen Linux Kernel 2.6.18 after
>     doing some needed changes,
>   - kexec-kernel-only_20121119.patch: patch fixes initial boot
>     structures overwrites on machines with memory larger than 1 GiB;
>     this is partial solution,
>   - kexec-kernel-only_20121203.patch: this patch fixes timer
>     issue on Amazon EC2 machines.

<snip>

> All code is GPL 2 licensed (http://www.gnu.org/licenses/gpl-2.0.html).
> Feel free to base your development on this patchset but please do not
> remove any copyrights. Addtionally, I am happy to help anybody who is
> interested in work on this stuff.
> 
> Big thank you for Acunu Ltd. (http://www.acunu.com/) for
> sponsoring initial work on Xen PV domU.

Thanks so much for releasing this code, it's much appreciated.  I'll
take this and work to get it merged upstream as much as possible.

greg k-h

Re: [PATCH] kexec/kdump implementation for Xen PV domU

[Matt Wilson]

On Mon, Jul 29, 2013 at 07:15:43PM +0200, Daniel Kiper wrote:
> Hi all,
> 
> Here I am sending as attachments patches enabling kexec/kdump
> support in Xen PV domU. Only x84_64 architecture is supported.
> There is no support for i386 but some code could be easily reused.
> Here is a description of patches:

[...]

>   - kexec-kernel-only_20121203.patch: this patch fixes timer
>     issue on Amazon EC2 machines.

Hi Daniel,

Do you know the cause of this issue? Does it have something to do with
singleshot timer migration when offlining/onlining SMP CPUs?

--msw

Re: [PATCH] kexec/kdump implementation for Xen PV domU

[Daniel Kiper]

On Mon, Jul 29, 2013 at 02:44:19PM -0700, Matt Wilson wrote:
> On Mon, Jul 29, 2013 at 07:15:43PM +0200, Daniel Kiper wrote:
> > Hi all,
> >
> > Here I am sending as attachments patches enabling kexec/kdump
> > support in Xen PV domU. Only x84_64 architecture is supported.
> > There is no support for i386 but some code could be easily reused.
> > Here is a description of patches:
>
> [...]
>
> >   - kexec-kernel-only_20121203.patch: this patch fixes timer
> >     issue on Amazon EC2 machines.
>
> Hi Daniel,
>
> Do you know the cause of this issue? Does it have something to do with
> singleshot timer migration when offlining/onlining SMP CPUs?

Sadly, no. I was not able to replicate this on my machines (I did test
on Xen 4.1). However, as I saw this issue appears on Xen 3.4 and 4.0
(IIRC version numbers used on your machines). Additionally, it does not
depend on CPU models. And it appears quite often but not always.
Maybe it is linked with singleshot timer migration.

Daniel