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Re: [Qemu-devel] On block interface types in general, IF_AHCI in particu
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular |
Date: |
Wed, 31 Oct 2012 15:09:09 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:16.0) Gecko/20121016 Thunderbird/16.0.1 |
Il 31/10/2012 14:58, Markus Armbruster ha scritto:
> So by default, you can have only two fast devices, and you get them only
> if you know that you need to use unit=4 and unit=5.
Or "-m q35".
> Naive usage, including -hda, gets IDE compatibility mode, which is slower.
>
> I think this is robbing Peter to pay Paul.
Everything is.
> Peters getting robbed:
>
> * New guests that would deal just fine with q35 including AHCI lose:
> they get "upgraded" to AHCI in IDE compatibility mode, which is slower
> than the real thing.
But also slower than virtio. :)
> * Existing guests that could deal with the hardware upgrade from i440FX
> to q35 just fine lose the same way.
>
> Pauls getting paid:
>
> * Existing guests that can deal with the upgrade *except* for AHCI
> *continue to work.
>
> And there are Pats who still won't get paid:
>
> * Existing guests that can't deal with the chipset changing under them
> still break.
Do we know of any?
> If we make q35 the default and q35 with compat IDE an option, then the
> Peters just work, and the Pauls and the Pats break on upgrade until you
> specify a machine type that works.
Is there anything that prevents us from doing it later?
Paolo
- [Qemu-devel] On block interface types in general, IF_AHCI in particular, Markus Armbruster, 2012/10/30
- Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular, Jason Baron, 2012/10/30
- Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular, Paolo Bonzini, 2012/10/30
- Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular, Kevin Wolf, 2012/10/30
- Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular, Anthony Liguori, 2012/10/30
- Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular, Anthony Liguori, 2012/10/30
- Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular, Markus Armbruster, 2012/10/31
- Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular, Peter Maydell, 2012/10/31
- Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular,
Paolo Bonzini <=
- Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular, Markus Armbruster, 2012/10/31
- Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular, Paolo Bonzini, 2012/10/31
- Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular, Alexander Graf, 2012/10/31
- Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular, Paolo Bonzini, 2012/10/31
- Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular, Anthony Liguori, 2012/10/31
- Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular, Alexander Graf, 2012/10/31
- Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular, Anthony Liguori, 2012/10/31
- Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular, Alexander Graf, 2012/10/31
- Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular, Anthony Liguori, 2012/10/31
- Re: [Qemu-devel] On block interface types in general, IF_AHCI in particular, Paolo Bonzini, 2012/10/31