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Commit 6aef266c authored by Srivatsa Vaddagiri's avatar Srivatsa Vaddagiri Committed by Gleb Natapov
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kvm hypervisor : Add a hypercall to KVM hypervisor to support pv-ticketlocks 



kvm_hc_kick_cpu allows the calling vcpu to kick another vcpu out of halt state.
the presence of these hypercalls is indicated to guest via
kvm_feature_pv_unhalt.

Fold pv_unhalt flag into GET_MP_STATE ioctl to aid migration
During migration, any vcpu that got kicked but did not become runnable
(still in halted state) should be runnable after migration.

Signed-off-by: default avatarSrivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: default avatarSuzuki Poulose <suzuki@in.ibm.com>
[Raghu: Apic related changes, folding pvunhalted into vcpu_runnable
 Added flags for future use (suggested by Gleb)]
[ Raghu: fold pv_unhalt flag as suggested by Eric Northup]
Signed-off-by: default avatarRaghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Acked-by: default avatarGleb Natapov <gleb@redhat.com>
Acked-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarGleb Natapov <gleb@redhat.com>
parent 4b0a8670

arch/x86/include/asm/kvm_host.h

+5 −0
Original line number Diff line number Diff line
@@ -516,6 +516,11 @@ struct kvm_vcpu_arch { 


	/* set at EPT violation at this point */

	unsigned long exit_qualification;



	/* pv related host specific info */

	struct {

		bool pv_unhalted;

	} pv;

};



struct kvm_lpage_info {

arch/x86/kvm/cpuid.c

+2 −1
Original line number Diff line number Diff line
@@ -413,7 +413,8 @@ static int do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function, 
			     (1 << KVM_FEATURE_CLOCKSOURCE2) |

			     (1 << KVM_FEATURE_ASYNC_PF) |

			     (1 << KVM_FEATURE_PV_EOI) |

			     (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT);

			     (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT) |

			     (1 << KVM_FEATURE_PV_UNHALT);



		if (sched_info_on())

			entry->eax |= (1 << KVM_FEATURE_STEAL_TIME);

arch/x86/kvm/x86.c

+43 −1
Original line number Diff line number Diff line
@@ -5588,6 +5588,36 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu) 
	return 1;

}



/*

 * kvm_pv_kick_cpu_op:  Kick a vcpu.

 *

 * @apicid - apicid of vcpu to be kicked.

 */

static void kvm_pv_kick_cpu_op(struct kvm *kvm, unsigned long flags, int apicid)

{

	struct kvm_vcpu *vcpu = NULL;

	int i;



	kvm_for_each_vcpu(i, vcpu, kvm) {

		if (!kvm_apic_present(vcpu))

			continue;



		if (kvm_apic_match_dest(vcpu, 0, 0, apicid, 0))

			break;

	}

	if (vcpu) {

		/*

		 * Setting unhalt flag here can result in spurious runnable

		 * state when unhalt reset does not happen in vcpu_block.

		 * But that is harmless since that should soon result in halt.

		 */

		vcpu->arch.pv.pv_unhalted = true;

		/* We need everybody see unhalt before vcpu unblocks */

		smp_wmb();

		kvm_vcpu_kick(vcpu);

	}

}



int kvm_emulate_hypercall(struct kvm_vcpu *vcpu)

{

	unsigned long nr, a0, a1, a2, a3, ret;
@@ -5621,6 +5651,10 @@ int kvm_emulate_hypercall(struct kvm_vcpu *vcpu) 
	case KVM_HC_VAPIC_POLL_IRQ:

		ret = 0;

		break;

	case KVM_HC_KICK_CPU:

		kvm_pv_kick_cpu_op(vcpu->kvm, a0, a1);

		ret = 0;

		break;

	default:

		ret = -KVM_ENOSYS;

		break;
@@ -6043,6 +6077,7 @@ static int __vcpu_run(struct kvm_vcpu *vcpu) 
				kvm_apic_accept_events(vcpu);

				switch(vcpu->arch.mp_state) {

				case KVM_MP_STATE_HALTED:

					vcpu->arch.pv.pv_unhalted = false;

					vcpu->arch.mp_state =

						KVM_MP_STATE_RUNNABLE;

				case KVM_MP_STATE_RUNNABLE:
@@ -6342,7 +6377,12 @@ int kvm_arch_vcpu_ioctl_get_mpstate(struct kvm_vcpu *vcpu, 
				    struct kvm_mp_state *mp_state)

{

	kvm_apic_accept_events(vcpu);

	if (vcpu->arch.mp_state == KVM_MP_STATE_HALTED &&

					vcpu->arch.pv.pv_unhalted)

		mp_state->mp_state = KVM_MP_STATE_RUNNABLE;

	else

		mp_state->mp_state = vcpu->arch.mp_state;



	return 0;

}
@@ -6863,6 +6903,7 @@ int kvm_arch_vcpu_init(struct kvm_vcpu *vcpu) 
	BUG_ON(vcpu->kvm == NULL);

	kvm = vcpu->kvm;



	vcpu->arch.pv.pv_unhalted = false;

	vcpu->arch.emulate_ctxt.ops = &emulate_ops;

	if (!irqchip_in_kernel(kvm) || kvm_vcpu_is_bsp(vcpu))

		vcpu->arch.mp_state = KVM_MP_STATE_RUNNABLE;
@@ -7200,6 +7241,7 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu) 
		!vcpu->arch.apf.halted)

		|| !list_empty_careful(&vcpu->async_pf.done)

		|| kvm_apic_has_events(vcpu)

		|| vcpu->arch.pv.pv_unhalted

		|| atomic_read(&vcpu->arch.nmi_queued) ||

		(kvm_arch_interrupt_allowed(vcpu) &&

		 kvm_cpu_has_interrupt(vcpu));