Re: [Xen-devel] [PATCH v3 00/11] xen: Initial kexec/kdump implementation

David Vrabel
2013-01-04T14:38:51Z

On 04/01/13 14:22, Daniel Kiper wrote:
> On Wed, Jan 02, 2013 at 11:26:43AM +0000, Andrew Cooper wrote:
>> On 27/12/12 18:02, Eric W. Biederman wrote:
>>> Andrew Cooper<andrew.cooper3@citrix.com> writes:
>>>
>>>> On 27/12/2012 07:53, Eric W. Biederman wrote:
>>>>> The syscall ABI still has the wrong semantics.
>>>>>
>>>>> Aka totally unmaintainable and umergeable.
>>>>>
>>>>> The concept of domU support is also strange. What does domU support even mean, when the dom0 support is loading a kernel to pick up Xen when Xen falls over.
>>>> There are two requirements pulling at this patch series, but I agree
>>>> that we need to clarify them.
>>> It probably make sense to split them apart a little even.
>>>
>>>
>>
>> Thinking about this split, there might be a way to simply it even more.
>>
>> /sbin/kexec can load the "Xen" crash kernel itself by issuing
>> hypercalls using /dev/xen/privcmd. This would remove the need for
>> the dom0 kernel to distinguish between loading a crash kernel for
>> itself and loading a kernel for Xen.
>>
>> Or is this just a silly idea complicating the matter?
>
> This is impossible with current Xen kexec/kdump interface.
> It should be changed to do that. However, I suppose that
> Xen community would not be interested in such changes.

I don't see why the hypercall ABI cannot be extended with new sub-ops
that do the right thing -- the existing ABI is a bit weird.

I plan to start prototyping something shortly (hopefully next week) for
the Xen kexec case.

David