[PATCH 5/5] arm/arm64: KVM: Turn off vcpus and flush stage-2 pgtables on sytem exit events

[Peter Maydell]

On 27 November 2014 at 23:10, Peter Maydell <peter.maydell at linaro.org> wrote:
> It seems odd to have this unmap happen on attempted system reset/powerdown,
> not on cpu init/start.

Here's a concrete case that I think requires the unmap to be
done on cpu init:
 * start a VM and run it for a bit
 * from the QEMU monitor, use "loadvm" to load a VM snapshot

This will cause QEMU to do a system reset (including calling
VCPU_INIT to reset the CPUs), load the contents of guest
RAM from the snapshot, set guest CPU registers with a pile
of SET_ONE_REG calls, and then KVM_RUN to start the VM.

If we don't unmap stage2 on vcpu init,  then what in this
sequence causes the icaches to be flushed so we execute
the newly loaded ram contents rather than stale data
from the first VM run?

thanks
-- PMM