From 6aef266c6e17b798a1740cf70cd34f90664740b3 Mon Sep 17 00:00:00 2001 From: Srivatsa Vaddagiri Date: Mon, 26 Aug 2013 14:18:34 +0530 Subject: [PATCH] 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: Srivatsa Vaddagiri Signed-off-by: Suzuki Poulose [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: Raghavendra K T Acked-by: Gleb Natapov Acked-by: Ingo Molnar Signed-off-by: Gleb Natapov --- arch/x86/include/asm/kvm_host.h | 5 +++++ arch/x86/kvm/cpuid.c | 3 ++- arch/x86/kvm/x86.c | 44 ++++++++++++++++++++++++++++++++++++++++- 3 files changed, 50 insertions(+), 2 deletions(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index c0efd16..c76ff74 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -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 { diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index a20ecb5..b110fe6 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -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); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 668f19a..c537417 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -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); - mp_state->mp_state = vcpu->arch.mp_state; + 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)); -- 2.7.4