Re: [PATCH] arm64: KVM: export current vcpu->pause state via pseudo regs

From: Paolo Bonzini
Date: Thu Jul 31 2014 - 12:57:52 EST

Il 09/07/2014 15:55, Alex BennÃe ha scritto:
> To cleanly restore an SMP VM we need to ensure that the current pause
> state of each vcpu is correctly recorded. Things could get confused if
> the CPU starts running after migration restore completes when it was
> paused before it state was captured.
> I've done this by exposing a register (currently only 1 bit used) via
> the GET/SET_ONE_REG logic to pass the state between KVM and the VM
> controller (e.g. QEMU).
> Signed-off-by: Alex BennÃe <alex.bennee@xxxxxxxxxx>
> ---
> arch/arm64/include/uapi/asm/kvm.h | 8 +++++
> arch/arm64/kvm/guest.c | 61 ++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 68 insertions(+), 1 deletion(-)

Since it's a pseudo register anyway, would it make sense to use the
existing KVM_GET/SET_MP_STATE ioctl interface?

How is this represented within QEMU in TCG mode? Also, how is KVM/ARM
representing (and passing to QEMU) the halted state of the VCPU?

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