[RFC PATCH] KVM: arm/arm64: Don't let userspace update CNTVOFF once guest is running

[Peter Maydell]

On 9 July 2015 at 13:05, Christoffer Dall <christoffer.dall at linaro.org> wrote:
> As I understand it, the problem is that if we ever run a VCPU after
> reading the value, and write back the value afterwards, you potentially
> make time go backwards and get inconsistent views of time from different
> VCPUs because they may have read the time before/after updating the
> CNTVOFF.

Right, but I think if QEMU does that it's a bug (and more to
the point I don't entirely understand why we would do that
yet, even given that we don't have a distinction between
"registers to sync always" and "registers to sync only on
reset"...)

-- PMM