Re: [PATCH v2 01/11] kexec: introduce kexec_ops struct

From: H. Peter Anvin
Date: Thu Nov 22 2012 - 20:39:26 EST


I still don't really get why it can't be isolated from dom0, which would make more sense to me, even for a Xen crash.

Andrew Cooper <andrew.cooper3@xxxxxxxxxx> wrote:

>On 22/11/2012 17:47, H. Peter Anvin wrote:
>> The other thing that should be considered here is how utterly
>> preposterous the notion of doing in-guest crash dumping is in a
>system
>> that contains a hypervisor. The reason for kdump is that on bare
>metal
>> there are no other options, but in a hypervisor system the right
>thing
>> should be for the hypervisor to do the dump (possibly spawning a
>clean
>> I/O domain if the I/O domain is necessary to access the media.)
>>
>> There is absolutely no reason to have a crashkernel sitting around in
>
>> each guest, consuming memory, and possibly get corrupt.
>>
>> -hpa
>>
>
>(Your reply to my email which I can see on the xen devel archive
>appears
>to have gotten lost somewhere inside the citrix email system, so
>apologies for replying out of order)
>
>The kdump kernel loaded by dom0 is for when Xen crashes, not for when
>dom0 crashes (although a dom0 crash does admittedly lead to a Xen
>crash)
>
>There is no possible way it could be a separate domain; Xen completely
>ceases to function as soon as jumps to the entry point of the kdump
>image.
>
>~Andrew

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