On Thu, Oct 05, 2017 at 09:32:02AM +0100, Marc Zyngier wrote:
> On 29/09/17 12:30, Andrew Jones wrote:
> > This prepares for more MP states to be used.
> >
> > Signed-off-by: Andrew Jones <drjones@xxxxxxxxxx>
> > ---
> > arch/arm/include/asm/kvm_host.h | 6 ++++--
> > arch/arm64/include/asm/kvm_host.h | 6 ++++--
> > virt/kvm/arm/arm.c | 26 ++++++++++++++------------
> > virt/kvm/arm/psci.c | 17 +++++------------
> > 4 files changed, 27 insertions(+), 28 deletions(-)
> >
> > diff --git a/arch/arm/include/asm/kvm_host.h b/arch/arm/include/asm/kvm_host.h
> > index 4a879f6ff13b..85f3c20b9759 100644
> > --- a/arch/arm/include/asm/kvm_host.h
> > +++ b/arch/arm/include/asm/kvm_host.h
> > @@ -171,8 +171,8 @@ struct kvm_vcpu_arch {
> > * here.
> > */
> >
> > - /* vcpu power-off state */
> > - bool power_off;
> > + /* Current VCPU MP state */
> > + u32 mp_state;
>
> What is the rational for not using a struct kvm_mp_state directly here?
> It is the same thing (a u32), but I certainly find it more explicit than
> a bare u32.
No good rationale, only inspiration from reading x86 code. I agree using
the struct makes more sense, though, so I'll change it.
>
> >
> > /* Don't run the guest (internal implementation need) */
> > bool pause;
> > @@ -227,6 +227,8 @@ int kvm_test_age_hva(struct kvm *kvm, unsigned long hva);
> >
> > struct kvm_vcpu *kvm_arm_get_running_vcpu(void);
> > struct kvm_vcpu __percpu **kvm_get_running_vcpus(void);
> > +void kvm_arm_vcpu_power_off(struct kvm_vcpu *vcpu);
> > +void kvm_arm_vcpu_power_on(struct kvm_vcpu *vcpu);
> > void kvm_arm_halt_guest(struct kvm *kvm);
> > void kvm_arm_resume_guest(struct kvm *kvm);
> >
> > diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> > index e923b58606e2..25545a87de11 100644
> > --- a/arch/arm64/include/asm/kvm_host.h
> > +++ b/arch/arm64/include/asm/kvm_host.h
> > @@ -255,8 +255,8 @@ struct kvm_vcpu_arch {
> > u32 mdscr_el1;
> > } guest_debug_preserved;
> >
> > - /* vcpu power-off state */
> > - bool power_off;
> > + /* Current VCPU MP state */
> > + u32 mp_state;
> >
> > /* Don't run the guest (internal implementation need) */
> > bool pause;
> > @@ -328,6 +328,8 @@ int kvm_test_age_hva(struct kvm *kvm, unsigned long hva);
> >
> > struct kvm_vcpu *kvm_arm_get_running_vcpu(void);
> > struct kvm_vcpu * __percpu *kvm_get_running_vcpus(void);
> > +void kvm_arm_vcpu_power_off(struct kvm_vcpu *vcpu);
> > +void kvm_arm_vcpu_power_on(struct kvm_vcpu *vcpu);
> > void kvm_arm_halt_guest(struct kvm *kvm);
> > void kvm_arm_resume_guest(struct kvm *kvm);
> >
> > diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> > index e4bec508ee5b..954e77608d29 100644
> > --- a/virt/kvm/arm/arm.c
> > +++ b/virt/kvm/arm/arm.c
> > @@ -368,21 +368,23 @@ void kvm_arch_vcpu_put(struct kvm_vcpu *vcpu)
> > kvm_timer_vcpu_put(vcpu);
> > }
> >
> > -static void vcpu_power_off(struct kvm_vcpu *vcpu)
> > +void kvm_arm_vcpu_power_off(struct kvm_vcpu *vcpu)
> > {
> > - vcpu->arch.power_off = true;
> > + vcpu->arch.mp_state = KVM_MP_STATE_STOPPED;
> > kvm_make_request(KVM_REQ_SLEEP, vcpu);
> > kvm_vcpu_kick(vcpu);
> > }
> >
> > +void kvm_arm_vcpu_power_on(struct kvm_vcpu *vcpu)
> > +{
> > + vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
> > + kvm_vcpu_kick(vcpu);
> > +}
> > +
> > int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu,
> > struct kvm_mp_state *mp_state)
> > {
> > - if (vcpu->arch.power_off)
> > - mp_state->mp_state = KVM_MP_STATE_STOPPED;
> > - else
> > - mp_state->mp_state = KVM_MP_STATE_RUNNABLE;
> > -
> > + mp_state->mp_state = vcpu->arch.mp_state;
> > return 0;
> > }
> >
> > @@ -391,10 +393,10 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
> > {
> > switch (mp_state->mp_state) {
> > case KVM_MP_STATE_RUNNABLE:
> > - vcpu->arch.power_off = false;
> > + kvm_arm_vcpu_power_on(vcpu);
> > break;
> > case KVM_MP_STATE_STOPPED:
> > - vcpu_power_off(vcpu);
> > + kvm_arm_vcpu_power_off(vcpu);
> > break;
> > default:
> > return -EINVAL;
> > @@ -405,7 +407,7 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
> >
> > static bool vcpu_should_sleep(struct kvm_vcpu *vcpu)
> > {
> > - return vcpu->arch.power_off || vcpu->arch.pause;
> > + return vcpu->arch.mp_state == KVM_MP_STATE_STOPPED || vcpu->arch.pause;
> > }
> >
> > /**
> > @@ -919,9 +921,9 @@ static int kvm_arch_vcpu_ioctl_vcpu_init(struct kvm_vcpu *vcpu,
> > * Handle the "start in power-off" case.
> > */
> > if (test_bit(KVM_ARM_VCPU_POWER_OFF, vcpu->arch.features))
> > - vcpu_power_off(vcpu);
> > + kvm_arm_vcpu_power_off(vcpu);
> > else
> > - vcpu->arch.power_off = false;
> > + kvm_arm_vcpu_power_on(vcpu);
> >
> > return 0;
> > }
> > diff --git a/virt/kvm/arm/psci.c b/virt/kvm/arm/psci.c
> > index f1e363bab5e8..a7bf152f1247 100644
> > --- a/virt/kvm/arm/psci.c
> > +++ b/virt/kvm/arm/psci.c
> > @@ -64,16 +64,13 @@ static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu)
> >
> > static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu)
> > {
> > - vcpu->arch.power_off = true;
> > - kvm_make_request(KVM_REQ_SLEEP, vcpu);
> > - kvm_vcpu_kick(vcpu);
> > + kvm_arm_vcpu_power_off(vcpu);
> > }
> >
> > static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
> > {
> > struct kvm *kvm = source_vcpu->kvm;
> > struct kvm_vcpu *vcpu = NULL;
> > - struct swait_queue_head *wq;
> > unsigned long cpu_id;
> > unsigned long context_id;
> > phys_addr_t target_pc;
> > @@ -90,7 +87,7 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
> > */
> > if (!vcpu)
> > return PSCI_RET_INVALID_PARAMS;
> > - if (!vcpu->arch.power_off) {
> > + if (vcpu->arch.mp_state != KVM_MP_STATE_STOPPED) {
>
> Would it make sense to have a new helper to wrap that condition (also
> used below)?
I'll see how it looks.
>
> > if (kvm_psci_version(source_vcpu) != KVM_ARM_PSCI_0_1)
> > return PSCI_RET_ALREADY_ON;
> > else
> > @@ -118,11 +115,7 @@ static unsigned long kvm_psci_vcpu_on(struct kvm_vcpu *source_vcpu)
> > * the general puspose registers are undefined upon CPU_ON.
> > */
> > vcpu_set_reg(vcpu, 0, context_id);
> > - vcpu->arch.power_off = false;
> > - smp_mb(); /* Make sure the above is visible */
> > -
> > - wq = kvm_arch_vcpu_wq(vcpu);
> > - swake_up(wq);
> > + kvm_arm_vcpu_power_on(vcpu);
>
> What guarantees that the mp_state update is now visible to other agents?
> Or was the smp_mb() here superfluous? This should anyhow deserve a
> mention in the commit message.
The smp_mb() was superfluous, as this has the same pattern as other
uses of prepare_to_swait/swake_up. I'll update the commit message
with more detail.
>
> >
> > return PSCI_RET_SUCCESS;
> > }
> > @@ -156,7 +149,7 @@ static unsigned long kvm_psci_vcpu_affinity_info(struct kvm_vcpu *vcpu)
> > mpidr = kvm_vcpu_get_mpidr_aff(tmp);
> > if ((mpidr & target_affinity_mask) == target_affinity) {
> > matching_cpus++;
> > - if (!tmp->arch.power_off)
> > + if (tmp->arch.mp_state != KVM_MP_STATE_STOPPED)
> > return PSCI_0_2_AFFINITY_LEVEL_ON;
> > }
> > }
> > @@ -182,7 +175,7 @@ static void kvm_prepare_system_event(struct kvm_vcpu *vcpu, u32 type)
> > * re-initialized.
> > */
> > kvm_for_each_vcpu(i, tmp, vcpu->kvm)
> > - tmp->arch.power_off = true;
> > + tmp->arch.mp_state = KVM_MP_STATE_STOPPED;
>
> Ah, shame we can't get rid of this with a power_off...
>
> > kvm_make_all_cpus_request(vcpu->kvm, KVM_REQ_SLEEP);
> >
> > memset(&vcpu->run->system_event, 0, sizeof(vcpu->run->system_event));
> >
>
> Thanks,
>
> M.
> --
> Jazz is not dead. It just smells funny...
Thanks for the review!
drew
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