[Crash-utility] [PATCH] xen: Add support for dom0 with Linux kernel 3.19 and newer

[Daniel Kiper]

Hi Dave,

Sorry for delay but I have missed your email.

On Thu, Jan 21, 2016 at 04:34:15PM -0500, Dave Anderson wrote:
>
> ----- Original Message -----
> >
> > Linux kernel commit 054954eb051f35e74b75a566a96fe756015352c8
> > (xen: switch to linear virtual mapped sparse p2m list), which
> > appeared in 3.19, introduced linear virtual mapped sparse p2m
> > list. If readmem() reads p2m then it access this list using
> > physical addresses. Sadly, VMA to physical address translation
> > in crash requires access to p2m list. This means that we have
> > a chicken and egg problem. In general this issue must be solved
> > by introducing some changes in libxl, Linux kernel and crash
> > (I have added this task to my long TODO list). However, in dom0
> > case we can use crash_xen_info_t.dom0_pfn_to_mfn_frame_list_list
> > which is available out of the box. So, let's use it and make
> > at least some users happy.
> >
> > Signed-off-by: Daniel Kiper <daniel.kiper at oracle.com>
>
> Hi Daniel,
>
> Can you help me out with a consise changelog entry?  As I understand
> it, the crash utility has not supported Xen dom0 and domU dumpfiles
> since the referenced 3.19 commit, and this patch resurrects support
> for dom0 dumpfiles only.  Are there issues with live system analysis

Exactly!

> as well?

I am not sure what do you mean by that. If you are asking about
crash commands then it looks that after my fix everything works
as expected.

> And without the patch, what is the final, fatal error message?

Here it is:

crash 7.1.4
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crash: cannot resolve "p2m_top"

Daniel