Re: [PATCH] KVM: x86: Convert INIT and SIPI signals into synchronously handled events

Jan Kiszka
2013-03-12T13:13:54Z

On 2013-03-12 14:09, Paolo Bonzini wrote:
> Il 12/03/2013 13:46, Jan Kiszka ha scritto:
>>>>>>>> @@ -6178,7 +6177,13 @@ int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,
>>>>>>>> int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
>>>>>>>> struct kvm_mp_state *mp_state)
>>>>>>>> {
>>>>>>>> - vcpu->arch.mp_state = mp_state->mp_state;
>>>>>>>> + if (mp_state->mp_state == KVM_MP_STATE_SIPI_RECEIVED) {
>>>>>>>> + if (!kvm_vcpu_has_lapic(vcpu))
>>>>>>>> + return -EINVAL;
>>>>>>>> + vcpu->arch.mp_state = KVM_MP_STATE_INIT_RECEIVED;
>>>>>>>> + set_bit(KVM_APIC_SIPI, &vcpu->arch.apic->pending_events);
>>>>>>>> + } else
>>>>>>>> + vcpu->arch.mp_state = mp_state->mp_state;
>>>>>>
>>>>>> Should INIT_RECEIVED also be invalid without an in-kernel LAPIC?
>>>>
>>>> And since migration was brought up yesterday, do we need an interface to
>>>> retrieve and set this?
>>>>
>>>> And should KVM_GET/SET_VCPU_EVENTS use the new sipi_vector in the APIC
>>>> rather than the old one?
>> I hope not. The idea is that the APIC events are processed before the
>> migration completes. Translating events on get_mpstate should ensure this.
>
> What about persistent state such as "an INIT has been received and
> caused a vmexit, but is being latched until vmxoff"? Perhaps we could
> use the top 8 bits of vcpu->arch.sipi_vector for this, they are always
> shifted out when sipi_vector is used, and should be zero in all cases.
> It would then be possible to reuse KVM_GET/SET_VCPU_EVENTS.

See my other mail.

>
> Migration support for nested VMX is still far far away, so perhaps we do
> not care, but we still need a way to inject INIT from userspace.

Ack for INIT injection. In theory, you could use the VCPU event IOCTL,
it is extensible. If that is elegant is another question.

Jan

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