Re: Xen & VMI?

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From: Jeremy Fitzhardinge
Date: Tuesday, March 6, 2007 - 9:42 am

Ingo Molnar wrote:

Of course it has relevance.  Linux is an important guest system, and not
supporting it would be a major problem.  I already have a list of things
which need to be done to Xen to make it work better with current kernels
- none of them mandatory, but nice to have.


"VMI" is not a promise, it's just three letters.  It doesn't even mean
the same thing now as it did 12 months ago.  Turning "VMI" from three
letters into anything remotely like a promise is a huge amount of work
which requires:

   1. someone actually sit down and fully document what all those
      entrypoints are going to do
   2. everyone to implement them
   3. someone to test that all the implementations conform to the
      document (bearing in mind that if anyone is going to go to all
      this effort, they're going to use this with non-Linux guests)
   4. and repeat all that every subsequent update

That's assuming all the parties involved are approaching the process
with goodwill.  If someone wanted to effectively stall the kernel's
development (at least in terms of useful kernels that people can keep
shipping and deploying), then all they have to do is drag their heels on
this "VMI" interface process.  All this heavyweight process is very
enterprisy, but it doesn't help Linux at all.

And given that the idea of multiple implementations of a complex ABI
like this will actually conform to a spec and/or each other is pretty
much pie-in-the-sky, the kernel will still have to deal with all the
quirks of multiple implementations anyway.

    J
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Messages in current thread:
[patch] paravirt: VDSO page is essential, Ingo Molnar, (Mon Mar 5, 5:06 am)
Re: [patch] paravirt: VDSO page is essential, Avi Kivity, (Mon Mar 5, 5:36 am)
Re: [patch] paravirt: VDSO page is essential, Ingo Molnar, (Mon Mar 5, 5:40 am)
Re: [patch] paravirt: VDSO page is essential, Avi Kivity, (Mon Mar 5, 6:00 am)
Re: [patch] paravirt: VDSO page is essential, Rusty Russell, (Mon Mar 5, 6:28 am)
Re: [patch] paravirt: VDSO page is essential, Rusty Russell, (Mon Mar 5, 6:32 am)
Re: [patch] paravirt: VDSO page is essential, Ingo Molnar, (Mon Mar 5, 6:38 am)
[patch] paravirt: re-enable COMPAT_VDSO, Ingo Molnar, (Mon Mar 5, 6:46 am)
Re: [patch] paravirt: VDSO page is essential, Ingo Molnar, (Mon Mar 5, 6:48 am)
Re: [patch] paravirt: VDSO page is essential, Ingo Molnar, (Mon Mar 5, 6:48 am)
Re: [patch] paravirt: VDSO page is essential, Ingo Molnar, (Mon Mar 5, 6:59 am)
Re: [patch] paravirt: VDSO page is essential, Avi Kivity, (Mon Mar 5, 7:10 am)
Re: [patch] paravirt: VDSO page is essential, Ingo Molnar, (Mon Mar 5, 7:10 am)
Re: [patch] paravirt: VDSO page is essential, Andi Kleen, (Mon Mar 5, 7:27 am)
Re: [patch] paravirt: VDSO page is essential, Andi Kleen, (Mon Mar 5, 7:28 am)
Re: [patch] paravirt: VDSO page is essential, Andi Kleen, (Mon Mar 5, 7:34 am)
Re: [patch] paravirt: VDSO page is essential, Andi Kleen, (Mon Mar 5, 7:58 am)
Re: [patch] paravirt: VDSO page is essential, Zachary Amsden, (Mon Mar 5, 1:11 pm)
Re: [patch] paravirt: VDSO page is essential, Andi Kleen, (Mon Mar 5, 1:16 pm)
Re: [patch] paravirt: VDSO page is essential, Ingo Molnar, (Mon Mar 5, 1:19 pm)
Re: [patch] paravirt: VDSO page is essential, Zachary Amsden, (Mon Mar 5, 1:33 pm)
Re: [patch] paravirt: VDSO page is essential, Zachary Amsden, (Mon Mar 5, 1:42 pm)
Re: [patch] paravirt: VDSO page is essential, Roland McGrath, (Mon Mar 5, 2:58 pm)
Re: [patch] paravirt: VDSO page is essential, Jeremy Fitzhardinge, (Mon Mar 5, 3:01 pm)
Re: [patch] paravirt: VDSO page is essential, Roland McGrath, (Mon Mar 5, 3:58 pm)
Re: [patch] paravirt: VDSO page is essential, Jeremy Fitzhardinge, (Mon Mar 5, 4:03 pm)
Re: [patch] paravirt: VDSO page is essential, Rusty Russell, (Mon Mar 5, 5:57 pm)
Re: [patch] paravirt: VDSO page is essential, Zachary Amsden, (Mon Mar 5, 6:03 pm)
Re: [patch] paravirt: VDSO page is essential, Rusty Russell, (Mon Mar 5, 6:11 pm)
Re: [patch] paravirt: VDSO page is essential, Jeremy Fitzhardinge, (Mon Mar 5, 6:14 pm)
Re: [patch] paravirt: VDSO page is essential, Zachary Amsden, (Mon Mar 5, 6:51 pm)
Re: [patch] paravirt: VDSO page is essential, Jeremy Fitzhardinge, (Mon Mar 5, 6:53 pm)
Re: [patch] paravirt: VDSO page is essential, Ingo Molnar, (Tue Mar 6, 12:35 am)
Re: [patch] paravirt: VDSO page is essential, Zachary Amsden, (Tue Mar 6, 12:42 am)
Re: [patch] paravirt: VDSO page is essential, Ingo Molnar, (Tue Mar 6, 12:50 am)
Xen & VMI?, Ingo Molnar, (Tue Mar 6, 1:19 am)
Re: [patch] paravirt: VDSO page is essential, Ingo Molnar, (Tue Mar 6, 1:34 am)
Re: Xen & VMI?, Gerd Hoffmann, (Tue Mar 6, 1:37 am)
Re: Xen & VMI?, Zachary Amsden, (Tue Mar 6, 1:48 am)
Re: Xen & VMI?, Ingo Molnar, (Tue Mar 6, 1:52 am)
Re: Xen & VMI?, Zachary Amsden, (Tue Mar 6, 2:03 am)
Re: Xen & VMI?, Jeremy Fitzhardinge, (Tue Mar 6, 2:07 am)
Re: Xen & VMI?, Ingo Molnar, (Tue Mar 6, 2:10 am)
Re: [patch] paravirt: VDSO page is essential, Roland McGrath, (Tue Mar 6, 2:13 am)
Re: [patch] paravirt: VDSO page is essential, Jeremy Fitzhardinge, (Tue Mar 6, 2:14 am)
Re: Xen & VMI?, Gerd Hoffmann, (Tue Mar 6, 2:15 am)
Re: Xen & VMI?, Ingo Molnar, (Tue Mar 6, 2:26 am)
Re: Xen & VMI?, Ingo Molnar, (Tue Mar 6, 2:34 am)
Re: Xen & VMI?, Avi Kivity, (Tue Mar 6, 2:55 am)
Re: Xen & VMI?, Gerd Hoffmann, (Tue Mar 6, 3:15 am)
Re: Xen & VMI?, Gerd Hoffmann, (Tue Mar 6, 3:23 am)
Re: Xen & VMI?, Ingo Molnar, (Tue Mar 6, 3:26 am)
Re: Xen & VMI?, Ingo Molnar, (Tue Mar 6, 3:31 am)
Re: Xen & VMI?, Gerd Hoffmann, (Tue Mar 6, 4:04 am)
Re: Xen & VMI?, Ingo Molnar, (Tue Mar 6, 4:59 am)
Re: Xen & VMI?, Gerd Hoffmann, (Tue Mar 6, 5:34 am)
Re: Xen & VMI?, Anthony Liguori, (Tue Mar 6, 8:03 am)
Re: Xen & VMI?, Jeremy Fitzhardinge, (Tue Mar 6, 9:27 am)
Re: Xen & VMI?, Jeremy Fitzhardinge, (Tue Mar 6, 9:42 am)
Re: Xen & VMI?, Ingo Molnar, (Tue Mar 6, 10:11 am)
RE: Xen & VMI?, Nakajima, Jun, (Tue Mar 6, 10:17 am)
Re: Xen & VMI?, Ingo Molnar, (Tue Mar 6, 10:18 am)
Re: Xen & VMI?, Anthony Liguori, (Tue Mar 6, 10:32 am)
Re: Xen & VMI?, Jeremy Fitzhardinge, (Tue Mar 6, 11:04 am)
Re: [patch] paravirt: VDSO page is essential, Jeremy Fitzhardinge, (Tue Mar 6, 11:48 am)
Re: Xen & VMI?, Chris Wright, (Tue Mar 6, 12:46 pm)
Re: Xen & VMI?, Ingo Molnar, (Tue Mar 6, 1:30 pm)
Re: Xen & VMI?, Ingo Molnar, (Tue Mar 6, 1:37 pm)
Re: Xen & VMI?, Chris Wright, (Tue Mar 6, 1:53 pm)
Re: Xen & VMI?, Jeremy Fitzhardinge, (Tue Mar 6, 2:02 pm)
Re: Xen & VMI?, Ingo Molnar, (Tue Mar 6, 2:03 pm)
Re: Xen & VMI?, Ingo Molnar, (Tue Mar 6, 2:11 pm)
Re: Xen & VMI?, Jeremy Fitzhardinge, (Tue Mar 6, 2:13 pm)
Re: Xen & VMI?, Ingo Molnar, (Tue Mar 6, 2:20 pm)
Re: Xen & VMI?, Chris Wright, (Tue Mar 6, 2:28 pm)
RE: Xen & VMI?, Nakajima, Jun, (Tue Mar 6, 2:35 pm)
Re: Xen & VMI?, Jeremy Fitzhardinge, (Tue Mar 6, 2:46 pm)
Re: Xen & VMI?, Rusty Russell, (Tue Mar 6, 5:44 pm)
Re: Xen & VMI?, Anthony Liguori, (Tue Mar 6, 5:54 pm)
Re: Xen & VMI?, Zachary Amsden, (Tue Mar 6, 7:16 pm)
Re: Xen & VMI?, Zachary Amsden, (Tue Mar 6, 7:35 pm)
Re: Xen & VMI?, Zachary Amsden, (Tue Mar 6, 8:06 pm)
Re: Xen & VMI?, Ingo Molnar, (Wed Mar 7, 1:15 am)
Re: Xen & VMI?, Zachary Amsden, (Wed Mar 7, 2:17 am)
Re: Xen & VMI?, Thomas Gleixner, (Wed Mar 7, 4:15 am)
Re: Xen & VMI?, Dan Hecht, (Wed Mar 7, 12:14 pm)