Re: [PATCH v1 0/5] target/arm/kvm: Provide an option to adjust virtual time

[Peter Maydell]

On Tue, 10 Dec 2019 at 11:05, Andrew Jones <address@hidden> wrote:
> x86 developers could easily add this feature if/when they need a way to
> disable their current default behavior. But, since the kvm-adjvtime
> default would likely be 'on' for them, then they'd probably prefer the
> feature be named kvm-no-adjvtime, and default 'off'. Should we try to
> anticipate what x86 might want when naming this feature? IMO, we should
> not, especially because I'm doubtful that x86 will ever want to implement
> it. Also, what about the other KVM capable architectures? Which defaults
> do they have now? And do we expect them to want to expose a switch to the
> user to change it?

My perspective here is mostly that I don't really understand
the ins and outs of KVM and in particular handling of
time in VMs, beyond knowing that it's complicated. So I
prefer approaches that push back to "do everything the same
for all architectures rather than having something that's
arm-specific", because then things get more review from
the larger mass of non-arm KVM/QEMU developers. Arm-specific
switches/interfaces/designs just make arm more of a
special-snowflake. I don't really have a basis to be able
to review the patchset beyond those general biases.

thanks
-- PMM