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Date: Mon, 21 Dec 2009 11:26:12 -0600
From: Anthony Liguori <anthony@codemonkey.ws>
MIME-Version: 1.0
Subject: Re: [Qemu-devel] Re: [SeaBIOS] [PATCH 0/8] option rom loading
	overhaul.
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To: Gleb Natapov <gleb@redhat.com>
Cc: Kevin O'Connor <kevin@koconnor.net>, Gerd Hoffmann <kraxel@redhat.com>, qemu-devel@nongnu.org

On 12/21/2009 10:43 AM, Gleb Natapov wrote:
>> There are some really ugly corner cases here.  For instance, guest
>> is running and the user does a yum update which upgrades the qemu
>> package.  This includes laying down a new bios.
>>
>> User eventually restarts guest, now we re-read BIOS and we're on a
>> newer BIOS than the device model.  Badness ensues.
>>
>>      
> My package manager warns me that certain application need to be
> restarted to work correctly after upgrade. This is hardly qemu specific
> problem.
>    

But again, I don't see when this is ever a feature that a user actually 
wants.  Unless you change restart to fork/exec+exit, you'll never have 
reset equivalent to power off + startup.  Can you advocate rereading 
roms and not advocate re-execing qemu?

>> And more importantly, what is the end-user benefit of doing this?
>>
>>      
> Working migration?
>    

How does it fix migration?  Migration needs to transfer the current roms 
in order to work.  A new version of qemu must support interacting with 
the old version of the firmware for migration to work.  What happens 
after reset has nothing to do with migration but because of the last 
requirement, the guest will obviously continue to work after reboot too.

Regards,

Anthony Liguori