[PATCH] arm64: KVM: export current vcpu->pause state via pseudo regs
alex.bennee at linaro.org
Fri Aug 1 02:11:52 PDT 2014
Christoffer Dall writes:
> On Thu, Jul 31, 2014 at 04:14:51PM +0100, Alex Bennée wrote:
>> Christoffer Dall writes:
>> > On Wed, Jul 09, 2014 at 02:55:12PM +0100, Alex Bennée wrote:
>> >> 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.
>> >> +/* Power state (PSCI), not real registers */
>> >> +#define KVM_REG_ARM_PSCI (0x0014 << KVM_REG_ARM_COPROC_SHIFT)
>> >> +#define KVM_REG_ARM_PSCI_REG(n) \
>> >> + (KVM_REG_ARM64 | KVM_REG_SIZE_U64 | KVM_REG_ARM_PSCI | \
>> >> + (n & ~KVM_REG_ARM_COPROC_MASK))
>> > I don't understand this mask, why isn't this
>> > (n & 0xffff))
>> I was trying to use the existing masks, but of course if anyone changes
>> that it would be an ABI change so probably not worth it.
> the KVM_REG_ARM_COPROC_MASK is part of the uapi IIRC, so that's not the
> issue, but that mask doesn't cover all the upper bits, so it feels weird
> to use that to me.
Yeah I missed that. I could do a:
#define KVM_REG_ARM_COPROC_INDEX_MASK ((1<<KVM_REG_ARM_COPROC_SHIFT)-1)
and use that. I'm generally try to avoid hardcoded numbers but I could
be being a little OCD here ;-)
>> > Can you add the 32-bit counterpart as part of this patch?
>> Same patch? Sure.
> really up to you if you want to split it up into two patches, but I
> think it's small enough that you can just create one patch.
Given the similarity of this code between arm and arm64 I'm wondering if
it's worth doing a arch/arm/kvm/guest_common.c or something to reduce
the amount of copy paste stuff?
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