linux-kernel - Re: [Xen-devel] [PATCH v2] xen, kdump: handle pv domain in paddr_vmcoreinfo

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Date:   Fri, 14 Apr 2017 18:53:36 +0200
From:   Petr Tesarik <ptesarik@...e.com>
To:     Daniel Kiper <daniel.kiper@...cle.com>
Cc:     Juergen Gross <jgross@...e.com>,
        Daniel Kiper <dkiper@...-space.pl>,
        linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org
Subject: Re: [Xen-devel] [PATCH v2] xen, kdump: handle pv domain in
 paddr_vmcoreinfo_note()

On Tue, 11 Apr 2017 19:20:08 +0200
Daniel Kiper <daniel.kiper@...cle.com> wrote:

> On Tue, Apr 11, 2017 at 04:59:16PM +0200, Petr Tesarik wrote:
>[...]
> > Tested-by: Petr Tesarik <ptesarik@...e.com>
> >
> > I copied the complete /proc/vmcore to a directory on disk. Exactly
> > as expected, crash works both without the patch and with the patch, as
> > it does not use VMCOREINFO at all (instead, crash obtains the
> > information from kernel debuginfo directly).
> 
> Thanks for doing the tests. I suppose that you have tested HVM guests.

Not really. I crashed Dom0, which is in turn sent to the hypervisor, so
the result is a complete host dump, including Xen hypervisor data and
all domains.

> IIRC, PV guests are not supported by crash right now due to p2m VMA
> mapping. At least it was an issue some time ago. Is it still valid?

Yes, this is correct. I tested this behaviour a few weeks ago.

> Anyway, one guy in Oracle works on fix for that issue and I do review.
> We are going to post it in 2-3 weeks.

All right. FYI I do not plan to put much effort into it, as my focus has
shifted towards libkdumpfile (https://github.com/ptesarik/libkdumpfile),
and this library can open PV guest dump files without any issues.

Petr T