Re: [Qemu-devel] [PATCH RFC 0/2] Versioning ARM virt machine types

[Peter Maydell <peter.maydell@linaro.org>]

On 22 February 2016 at 21:06, Wei Huang <wei@redhat.com> wrote:
> We start to see more features been added to ARM virtual machine models.
> For the purpose of backward compatibility (e.g. migration), it is time
> to consider versioning machine types for ARM VMs. As a beginning step, this
> patchset defines an abstract machine type for ARM VMs. The current
> "virt" machine is re-written based on this new machine type accordingly.
> These patches have been verified by booting existing VMs.
>
> Note that I am seeking inputs from the community by putting RFC in the
> subject line. Please let me know your opinions. I will send out V1
> afterwards.

My view here is the same as it has been in the past regarding
adding versioned machine types for 'virt': are you (in this case
Redhat) willing to stand behind it, in the sense of taking on
the maintenance burden of adding new machine versions, reviewing
new code contributions for issues that require changes to make sure
that the old versions stay looking like the old machine, testing
that old versions look right, testing cross version migration,
and so on?

We need versioned machine types at *some* point; my intent here
is to provide sufficient pushback to ensure that we don't give
ourselves the maintenance headache until we truly need it...

thanks
-- PMM