On Fri, Mar 21, 2014 at 06:23:33PM +0530, Anup Patel wrote: > This patch adds emulation of PSCI v0.2 CPU_SUSPEND function call for > KVM ARM/ARM64. This is a CPU-level function call which can suspend > current CPU or current CPU cluster. We don't have VCPU clusters in > KVM so for KVM we simply suspend the current VCPU. > > The CPU_SUSPEND emulation is not tested much because currently there > is no CPUIDLE driver in Linux kernel that uses PSCI CPU_SUSPEND. The > PSCI CPU_SUSPEND implementation in ARM64 kernel was tested using a > Simple CPUIDLE driver which is not published due to unstable DT-bindings > for PSCI. > (For more info, http://lwn.net/Articles/574950/) > > Even if we had stable DT-bindings for PSCI and CPUIDLE driver that > uses PSCI CPU_SUSPEND then still we need to define SUSPEND states > for KVM ARM/ARM64. > > Due to this, the CPU_SUSPEND emulation added by this patch only pause > current VCPU and to wakeup a suspended VCPU we need to explicity call > PSCI CPU_ON from Guest. > > Signed-off-by: Anup Patel <anup.patel@xxxxxxxxxx> > Signed-off-by: Pranavkumar Sawargaonkar <pranavkumar@xxxxxxxxxx> > --- > arch/arm/kvm/psci.c | 24 ++++++++++++++++++++---- > 1 file changed, 20 insertions(+), 4 deletions(-) > > diff --git a/arch/arm/kvm/psci.c b/arch/arm/kvm/psci.c > index 1e85452..e32ad10 100644 > --- a/arch/arm/kvm/psci.c > +++ b/arch/arm/kvm/psci.c > @@ -52,6 +52,22 @@ static unsigned long psci_affinity_mask(unsigned long affinity_level) > return affinity_mask; > } > > +static unsigned long kvm_psci_vcpu_suspend(struct kvm_vcpu *vcpu) > +{ > + /* > + * NOTE: Currently, we don't have any wakeup events for KVM > + * hence VCPU suspend turns-out to be same as VCPU off request. > + * This means to suspend a VCPU we simply set the pause flag > + * and update VCPU registers as-per wakeup parameters provided > + * via r2 & r3 (or x2 & x3). > + */ > + vcpu->arch.pause = true; > + *vcpu_pc(vcpu) = *vcpu_reg(vcpu, 2); > + *vcpu_reg(vcpu, 0) = *vcpu_reg(vcpu, 3); But the spec states in Section 5.1.2 that if Bit[16] StateType == 0, then the entry point and context_id parameters are ignored, because all state is retained for a standby state. I think Mark Rutland commented that KVM should define at last interrupts to the CPU as a wakeup event. > + > + return KVM_PSCI_RET_SUCCESS; > +} > + > static void kvm_psci_vcpu_off(struct kvm_vcpu *vcpu) > { > vcpu->arch.pause = true; > @@ -195,6 +211,10 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) > */ > val = 2; > break; > + case KVM_PSCI_0_2_FN_CPU_SUSPEND: > + case KVM_PSCI_0_2_FN64_CPU_SUSPEND: > + val = kvm_psci_vcpu_suspend(vcpu); > + break; > case KVM_PSCI_0_2_FN_CPU_OFF: > kvm_psci_vcpu_off(vcpu); > val = KVM_PSCI_RET_SUCCESS; > @@ -232,10 +252,6 @@ static int kvm_psci_0_2_call(struct kvm_vcpu *vcpu) > val = KVM_PSCI_RET_SUCCESS; > ret = 0; > break; > - case KVM_PSCI_0_2_FN_CPU_SUSPEND: > - case KVM_PSCI_0_2_FN64_CPU_SUSPEND: > - val = KVM_PSCI_RET_NI; > - break; > default: > return -EINVAL; > } > -- > 1.7.9.5 > Thanks, -Christoffer _______________________________________________ kvmarm mailing list kvmarm@xxxxxxxxxxxxxxxxxxxxx https://lists.cs.columbia.edu/mailman/listinfo/kvmarm
