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Date: Fri, 19 Dec 2014 16:51:05 +0000
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Subject: Re: [Qemu-devel] [Qemu-ppc] Unable to loadvm on qemu-system-ppc -M
 g3beige (keyboard freeze)
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To: Peter Maydell <peter.maydell@linaro.org>
Cc: "qemu-ppc@nongnu.org" <qemu-ppc@nongnu.org>, Alexander Graf <agraf@suse.de>, qemu-devel <qemu-devel@nongnu.org>

On 19/12/14 16:35, Peter Maydell wrote:

> On 19 December 2014 at 16:15, Mark Cave-Ayland
> <mark.cave-ayland@ilande.co.uk> wrote:
>> It looks like after restoring the CPU state with loadvm env->htab_base
>> is still at 0x0 rather than its pre-migration value of 0x7e000000.
> 
> Odd -- there is code that is at least trying to do that:
> machine.c calls ppc_store_sdr1() which should set htab_base/mask
> according to the migrated value of the register...

Stepping through ppc_store_sdr1() I see the problem is the if() statement:

if (env->spr[SPR_SDR1] != value) {
   ....
}

It looks like env->spr[SPR_SDR1] has already been set to 0x7e000000
before the call to ppc_store_sdr1() and so as the values are already
equal then the code to setup env->htab_mask and env->htab_base is bypassed.

The quick fix is to comment out the above if() statement which allows me
to restore my OpenBIOS image successfully with -loadvm but sadly not my
OS image (I guess there are probably a few more state bugs still lying
around). Does this seem the right thing to do or is there a better way?


ATB,

Mark.