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From: Juan Quintela <quintela@redhat.com>
In-Reply-To: <1298982742-31154-2-git-send-email-peter.maydell@linaro.org>
	(Peter Maydell's message of "Tue, 1 Mar 2011 12:32:21 +0000")
References: <1298982742-31154-1-git-send-email-peter.maydell@linaro.org>
	<1298982742-31154-2-git-send-email-peter.maydell@linaro.org>
Date: Tue, 01 Mar 2011 14:39:19 +0100
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Subject: [Qemu-devel] Re: [PATCH 1/2] hw/arm_sysctl.c: Add the Versatile
	Express system registers
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: patches@linaro.org, Dawid@gnu.org, qemu-devel@nongnu.org, Amit Mahajan <amit.mahajan@b-labs.com>, =?utf-8?Q?Ci=C4=99=C5=BCarkiewicz?= <dawidc@b-labs.com>, Bahadir Balban <bbalban@b-labs.com>

Peter Maydell <peter.maydell@linaro.org> wrote:

Hi

> @@ -41,6 +44,9 @@ static const VMStateDescription vmstate_arm_sysctl = {
>          VMSTATE_UINT32(flags, arm_sysctl_state),
>          VMSTATE_UINT32(nvflags, arm_sysctl_state),
>          VMSTATE_UINT32(resetlevel, arm_sysctl_state),
> +        VMSTATE_UINT32(sys_cfgdata, arm_sysctl_state),
> +        VMSTATE_UINT32(sys_cfgctrl, arm_sysctl_state),
> +        VMSTATE_UINT32(sys_cfgstat, arm_sysctl_state),
>          VMSTATE_END_OF_LIST()
>      }
>  };

Three options (about migration):
- left things as they are and become incompatible without changing versions
- if you don't care about backward compatibility, just add +1 to all the
  version fields and you are done.
- add this fields only for the new version.

IMHO 1st one is the worse option.  I will go with the middle one (as far
as I know, nobody on arm uses interversion migration (as far as I know,
nobody uses migration at all).

If you (or anybody else does), a pointer to one setup that is known to
work is welcome.

Later, Juan.