[Crash-utility] Re: Xen Hypervisor analysis

[Itsuro ODA]

Hi,

On Fri, Aug 08, 2008 at 11:15:17AM -0400, Dave Anderson wrote:
> 
> Gentlemen,
> 
> Our QA guys have started spending some time with Xen hypervisor
> crash analysis, and one obvious shortcoming is the implementation
> of the "search" command.
> 
> I don't see how it ever could have worked correctly, but in
> its current state, it either causes segmentation violations,
> or quietly runs but doesn't find anything.

I'm sorry. I have missed testing it actually.

> The primary problem is that the search command code is very
> linux-specific, and so the search command or command-options
> typically go off into the weeds trying to handle the addresses
> as linux virtual addresses.
> 
> Here's what I plan to do for the Xen hypervisor search command:
> 
>  1. Disallow the "-u" option, which is nonsensical.
>  2. Disallow the "-k" option, because of the various identity-mapped
>     and virtual address ranges used by the various architectures
>     is more than I care to deal with.
>  3. Do not translate the virtual addresses to physical before
>     reading the memory, i.e., just keep the addresses virtual.
>  4. Require either a "-s <address>" starting address or a Xen hypervisor
>     symbol as the starting address.
>  5. While cycling through memory, as soon as a page is encountered
>     that cannot be read, the search will be stopped.

It sounds reasonable.

> I'm hoping to get a new release out shortly, and you can see what
> I plan to do.  If you guys have a desire to extend the capability
> beyond 1-5 above, send me patches.
> 
> Thanks,
>   Dave Anderson

Thanks.
-- 
Itsuro ODA <oda at valinux.co.jp>