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[Qemu-devel] Re: [PATCH V3] floppy: save and restore DIR register
From: |
Jason Wang |
Subject: |
[Qemu-devel] Re: [PATCH V3] floppy: save and restore DIR register |
Date: |
Fri, 1 Apr 2011 18:03:37 +0800 |
Paolo Bonzini writes:
> On 04/01/2011 08:22 AM, Jason Wang wrote:
> > +
> > + if (drive->bs == NULL) {
> > + return 1;
>
> Is it okay to return 1 here? Have you tested the case when both the
> source and the target drives have no floppy?
>
Thanks for the reminding, and it could be fixed by put all pre/post callbacks
into the subsections.
> (The "media_changed == 2" in my sample code was basically a way to save
> the "media present" state of the drive on the source).
>
Right, but it would make subsection saving be the common case (consider most of
the vm may just have one floppy but we have two drives). A better solution
maybe:
1 Set default_migration_media_changed be 0 for 0.15 and 1 for elder
2 Unconditiaonlly send subsection when it was 0, and do not send subsection when
it was 1
3 Set media_changed to default_migration_media_changed in pre_load()
4 Let all pre/post to be in subsection
After those, we can make sure the migration between 0.15 could get correct
media_changed, also make sure the seamless migration between 0.15 and older
machine types.
Any suggestions?
> > + } else {
> > + drive->bs->media_changed = drive->media_changed;
> > + return 0;
> > + }
>
> The code is also missing the case of a pc-0.14 machine. The problem
> here is that the pc-0.15 machine hasn't been created yet, you get the
> honor. :(
>
Would create such one :)
> Paolo