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Re: [Qemu-devel] [PATCH v3] hw/i386: Deprecate the machines pc-0.10 to p
From: |
Eduardo Habkost |
Subject: |
Re: [Qemu-devel] [PATCH v3] hw/i386: Deprecate the machines pc-0.10 to pc-1.2 |
Date: |
Thu, 13 Jul 2017 12:20:10 -0300 |
User-agent: |
Mutt/1.8.0 (2017-02-23) |
On Thu, Jul 13, 2017 at 04:00:00AM +0300, Michael S. Tsirkin wrote:
> On Wed, Jul 12, 2017 at 10:22:33AM +0200, Thomas Huth wrote:
> > We don't want to carry along old machine types forever. If we are able to
> > remove the pc machines up to 0.13 one day for example, this would allow
> > us to eventually kill the code for rombar=0 (i.e. where QEMU copies ROM
> > BARs directly to low memory). Everything up to pc-1.2 is also known to
> > have issues with migration. So let's start with a deprecation message
> > for the old machine types so that the (hopefully) few users of these old
> > systems start switching over to newer machine types instead.
> >
> > Signed-off-by: Thomas Huth <address@hidden>
> > ---
> > Note: Even if we mark all these old machines as deprecated, this ofcourse
> > doesn't mean that we also have to remove them all at once later when we
> > decide to finally really remove some. We could then also start by removing
> > 0.10 and 0.11 only, for example (since there should really be no users left
> > for these), or only up to 0.13 (to be able to kill rombar=0).
>
> So I generally think the main issue is that machine types are conflating
> two things. One is saying "I want to be able to migrate from/to QEMU X".
> Another is saying "I want to look to guests as if I am QEMU X
> but I restart gurst on the new QEMU".
>
> First is generally a superset of the second, but only a subset of
> users needs the first. And while there's a very good chance we
> are actually pretty close to supporting the second even for very
> old machine types, I doubt we are actually able to migrate to/from
> these old QEMU versions since it is so hard to test.
>
> So IMHO, a more significant step with a long term impact would be to
> support splitting these things up.
I agree they are different things, but do we really have
volunteers willing to maintain a machine-type just because of the
latter? Setting the same deprecation policy for the two features
sounds simpler to me.
--
Eduardo
- Re: [Qemu-devel] [PATCH v3] hw/i386: Deprecate the machines pc-0.10 to pc-1.2, (continued)
- Re: [Qemu-devel] [PATCH v3] hw/i386: Deprecate the machines pc-0.10 to pc-1.2, Daniel P. Berrange, 2017/07/12
- Re: [Qemu-devel] [PATCH v3] hw/i386: Deprecate the machines pc-0.10 to pc-1.2, Paolo Bonzini, 2017/07/12
- Re: [Qemu-devel] [PATCH v3] hw/i386: Deprecate the machines pc-0.10 to pc-1.2, Daniel P. Berrange, 2017/07/12
- Re: [Qemu-devel] [PATCH v3] hw/i386: Deprecate the machines pc-0.10 to pc-1.2, Eduardo Habkost, 2017/07/12
- Re: [Qemu-devel] [PATCH v3] hw/i386: Deprecate the machines pc-0.10 to pc-1.2, Michael S. Tsirkin, 2017/07/13
Re: [Qemu-devel] [PATCH v3] hw/i386: Deprecate the machines pc-0.10 to pc-1.2, Eduardo Habkost, 2017/07/12
Re: [Qemu-devel] [PATCH v3] hw/i386: Deprecate the machines pc-0.10 to pc-1.2, Laszlo Ersek, 2017/07/12
Re: [Qemu-devel] [PATCH v3] hw/i386: Deprecate the machines pc-0.10 to pc-1.2, Michael S. Tsirkin, 2017/07/12
- Re: [Qemu-devel] [PATCH v3] hw/i386: Deprecate the machines pc-0.10 to pc-1.2,
Eduardo Habkost <=