move hyperv CHANNELMSG_UNLOAD from crashed kernel to kdump kernel

From	Olaf Hering <olaf@aepfle.de>
Newsgroups	linux.kernel
Subject	move hyperv CHANNELMSG_UNLOAD from crashed kernel to kdump kernel
Date	2016-12-07 10:00 +0100
Message-ID	<sLGf0-6eS-33@gated-at.bofh.it> (permalink)
Organization	linux.* mail to news gateway

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KY,

if a hyperv VM crashes alot of work must be done to prepare the
environment for the kdump kernel. This approach is different compared to
all the other VM types, or baremetal. Since the just crashed kernel is
per definition unreliable all that work should be done within the kdump
kernel because I think a reliable environment exists only there.

Was it ever considered to do the CHANNELMSG_UNLOAD /
CHANNELMSG_UNLOAD_RESPONSE work during boot, instead of doing it before
starting the kexec/kdump kernel?

What would it take to prepare the runtime environment during boot?
Does the newly booted kernel need any info from the previous kernel,
something that cant be determined during boot? If yes, how can such info
be passed from the old kernel to the new kernel?

Olaf

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move hyperv CHANNELMSG_UNLOAD from crashed kernel to kdump kernel Olaf Hering <olaf@aepfle.de> - 2016-12-07 10:00 +0100
  RE: move hyperv CHANNELMSG_UNLOAD from crashed kernel to kdump kernel KY Srinivasan <kys@microsoft.com> - 2016-12-07 16:10 +0100
    RE: move hyperv CHANNELMSG_UNLOAD from crashed kernel to kdump kernel Olaf Hering <olaf@aepfle.de> - 2016-12-07 17:00 +0100
      Re: move hyperv CHANNELMSG_UNLOAD from crashed kernel to kdump kernel Olaf Hering <olaf@aepfle.de> - 2016-12-07 17:20 +0100
        RE: move hyperv CHANNELMSG_UNLOAD from crashed kernel to kdump kernel KY Srinivasan <kys@microsoft.com> - 2016-12-07 17:30 +0100
          Re: move hyperv CHANNELMSG_UNLOAD from crashed kernel to kdump kernel Olaf Hering <olaf@aepfle.de> - 2016-12-07 17:50 +0100
            RE: move hyperv CHANNELMSG_UNLOAD from crashed kernel to kdump kernel KY Srinivasan <kys@microsoft.com> - 2016-12-07 21:50 +0100
      RE: move hyperv CHANNELMSG_UNLOAD from crashed kernel to kdump kernel KY Srinivasan <kys@microsoft.com> - 2016-12-07 17:20 +0100

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