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Date: Wed, 05 Mar 2014 22:48:24 +0100
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Subject: Re: [Qemu-devel] [PATCH 0/2] PC: improve emulation correctness
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: =?ISO-8859-1?Q?Herv=E9_Pouss?= =?ISO-8859-1?Q?ineau?= <hpoussin@reactos.org>, qemu-devel@nongnu.org, Anthony Liguori <aliguori@amazon.com>, "Michael S. Tsirkin" <mst@redhat.com>

Le 05/03/2014 09:15, Paolo Bonzini a =E9crit :
> Il 05/03/2014 00:49, Michael S. Tsirkin ha scritto:
>> On Mon, Mar 03, 2014 at 11:05:17PM +0100, Herv=E9 Poussineau wrote:
>>> Ping.
>>>
>>> QEMU crash at reboot is due to not resetting PAM registers at i440fx
>>> reset, but a patch has already been rejected on ML:
>>> http://lists.gnu.org/archive/html/qemu-devel/2013-02/msg02928.html
>>>
>>> Herv=E9
>>
>> I thought an alternative fix is being worked on?
>> http://lists.gnu.org/archive/html/qemu-devel/2013-02/msg02967.html
>
> Herv=E9, how does the BIOS do the reset?
>
> Paolo

At cold boot, BIOS is shadowed to RAM, and then hot-patched, so a warm bo=
ot won't do the same thing.
At BIOS exit, BIOS jumps to the new warm boot path.
This warm path doesn't work and crashes QEMU with "qemu: fatal: Trying to=
 execute code outside RAM or ROM at 0x000a1249" ; I've no idea why exactl=
y.
Resetting PAM registers prevents the shadowed copy to be visible, and BIO=
S does again a cold boot, which works.

Herv=E9