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Re: [Qemu-stable] [Qemu-devel] [PATCH for-1.4 0/2] fix migration failure
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-stable] [Qemu-devel] [PATCH for-1.4 0/2] fix migration failure from 1.3 due to SeaBIOS size change |
Date: |
Tue, 30 Apr 2013 19:30:57 +0300 |
On Tue, Apr 30, 2013 at 11:22:41AM -0500, Anthony Liguori wrote:
> "Michael S. Tsirkin" <address@hidden> writes:
>
> > On Tue, Feb 05, 2013 at 09:08:20PM -0600, Anthony Liguori wrote:
> >> Michael Roth <address@hidden> writes:
> >>
> >> > Migration from 1.3 currently fails due to a mismatch between the
> >> > expected size
> >> > of 256KB and the received size of 128KB for seabios. This series
> >> > attempts to
> >> > fix the issue by allowing a resize function to be registered to handle
> >> > resizing
> >> > memory blocks to accomodate the source's, and using that to re-initialize
> >> > "pc.bios" and "isa-bios" MemoryRegions based on the size of the incoming
> >> > block.
> >> >
> >> > There are also 2 potential alternatives to this patch set:
> >> >
> >> > 1) When I compile seabios 1.7.2 locally I end up with a 128KB binary.
> >>
> >> So do I on Fedora 18. Unless someone has a reason why this is a bad
> >> thing, I'll commit a 128kb binary and we can avoid this problem for 1.4.
> >>
> >> Obviously, we need to figure it out but that at least buys us some time...
> >>
> >> Regards,
> >>
> >> Anthony Liguori
> >
> > So we never bothered with this patch, and so it's still out.
> > How about we apply this for 1.5?
>
> This problem occurred because Gerd built SeaBIOS on RHEL6.x which
> resulted in a 256k binary.
>
> On F18, we're still fitting in 128k. There is no reason to worry about
> BIOS size right now.
>
> At some point, we will need to split into two separate BIOSes--a 128Kb
> and a 256Kb. This can be handled by having two SeaBIOS configuration
> files where one has a reduced feature set.
>
> We then would create an i440fx property that selects either the 128Kb or
> 256Kb BIOS. This property can then be setup as part of machine globals.
>
> So -M 1.4 or -M 1.5 will always use a 128Kb BIOS. If we need to, 1.6
> may end up with a 256Kb BIOS.
>
> > This way we, at least, won't have the problem with -M1.5 in the future.
> > Barring that - early in 1.6 cycle?
>
> The problem with Mike's patch is that it only solves older -> newer.
> The solution I outlined above also works for newer -> older.
>
> Regards,
>
> Anthony Liguori
Why doesn't the same approach work for new->old?
I am guessing you are talking about migration to 1.4 and older?
> >
> > --
> > MST