From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ian Campbell <Ian.Campbell@citrix.com>
Subject: Re: [PATCH] tools/libxc: Disable CONFIG_MIGRATE in
 stubdom environments
Date: Tue, 27 Jan 2015 17:01:23 +0000
Message-ID: <1422378083.16180.12.camel@citrix.com>
References: <1422377886-10334-1-git-send-email-andrew.cooper3@citrix.com>
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To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Wei Liu <wei.liu2@citrix.com>, Ian Jackson <Ian.Jackson@eu.citrix.com>, Xen-devel <xen-devel@lists.xen.org>
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On Tue, 2015-01-27 at 16:58 +0000, Andrew Cooper wrote:
> The legacy save/restore infrastructure requires several function pointers from
> the toolstack (libxl or Xend in the past) in order to work, and for HVM guests
> also need to be able to play around in dom0's filesystem to move the device
> model save record.
> 
> Migration v2 changes some of this, but is similarly dependent on
> toolstack-provided function pointers.
> 
> Someone who wishes to re-architect the interaction of moving parts for running
> a domain might be in a position to re-enabled this, but for now, explicitly
> fail with ENOSYS (from xc_nomigrate.c) rather than failing with an error about
> a missing function pointer (or indeed falling over a NULL pointer on certain
> paths).

You are talking about a toolstack which is itself running in a stubdom
here, right?

As opposed to e.g. an HVM domain using a qemu-stubdom, but being
migrated by a normal toolstack in domain 0 (or at least, not in a
mini-os based stubdom).

Ian.

> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
> CC: Ian Campbell <Ian.Campbell@citrix.com>
> CC: Ian Jackson <Ian.Jackson@eu.citrix.com>
> CC: Wei Liu <wei.liu2@citrix.com>
> ---
>  tools/libxc/Makefile |    5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/tools/libxc/Makefile b/tools/libxc/Makefile
> index bd2ca6c..735afdb 100644
> --- a/tools/libxc/Makefile
> +++ b/tools/libxc/Makefile
> @@ -4,6 +4,11 @@ include $(XEN_ROOT)/tools/Rules.mk
>  MAJOR    = 4.5
>  MINOR    = 0
>  
> +ifeq ($(CONFIG_LIBXC_MINIOS),y)
> +# Save/restore of a domain is currently incompatible with a stubdom environment
> +override CONFIG_MIGRATE := n
> +endif
> +
>  CTRL_SRCS-y       :=
>  CTRL_SRCS-y       += xc_core.c
>  CTRL_SRCS-$(CONFIG_X86) += xc_core_x86.c