kvm hypervisor : Add a hypercall to KVM hypervisor to support pv-ticketlocks From: Srivatsa Vaddagiri <vatsa@xxxxxxxxxxxxxxxxxx> 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. Signed-off-by: Srivatsa Vaddagiri <vatsa@xxxxxxxxxxxxxxxxxx> Signed-off-by: Suzuki Poulose <suzuki@xxxxxxxxxx> [Raghu: Apic related changes, folding pvunhalted into vcpu_runnable Added flags for future use (suggested by Gleb)] Signed-off-by: Raghavendra K T <raghavendra.kt@xxxxxxxxxxxxxxxxxx> --- arch/x86/include/asm/kvm_host.h | 5 +++++ arch/x86/include/uapi/asm/kvm_para.h | 1 + arch/x86/kvm/cpuid.c | 3 ++- arch/x86/kvm/x86.c | 37 ++++++++++++++++++++++++++++++++++ include/uapi/linux/kvm_para.h | 1 + 5 files changed, 46 insertions(+), 1 deletion(-) diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h index f87f7fc..1d1f711 100644 --- a/arch/x86/include/asm/kvm_host.h +++ b/arch/x86/include/asm/kvm_host.h @@ -511,6 +511,11 @@ struct kvm_vcpu_arch { * instruction. */ bool write_fault_to_shadow_pgtable; + + /* pv related host specific info */ + struct { + bool pv_unhalted; + } pv; }; struct kvm_lpage_info { diff --git a/arch/x86/include/uapi/asm/kvm_para.h b/arch/x86/include/uapi/asm/kvm_para.h index 06fdbd9..94dc8ca 100644 --- a/arch/x86/include/uapi/asm/kvm_para.h +++ b/arch/x86/include/uapi/asm/kvm_para.h @@ -23,6 +23,7 @@ #define KVM_FEATURE_ASYNC_PF 4 #define KVM_FEATURE_STEAL_TIME 5 #define KVM_FEATURE_PV_EOI 6 +#define KVM_FEATURE_PV_UNHALT 7 /* The last 8 bits are used to indicate how to interpret the flags field * in pvclock structure. If no bits are set, all flags are ignored. 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 d21bce5..dae4575 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -5495,6 +5495,36 @@ 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; @@ -5528,6 +5558,10 @@ 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; @@ -5950,6 +5984,7 @@ 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: @@ -6770,6 +6805,7 @@ 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; @@ -7103,6 +7139,7 @@ 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)); diff --git a/include/uapi/linux/kvm_para.h b/include/uapi/linux/kvm_para.h index cea2c5c..2841f86 100644 --- a/include/uapi/linux/kvm_para.h +++ b/include/uapi/linux/kvm_para.h @@ -19,6 +19,7 @@ #define KVM_HC_MMU_OP 2 #define KVM_HC_FEATURES 3 #define KVM_HC_PPC_MAP_MAGIC_PAGE 4 +#define KVM_HC_KICK_CPU 5 /* * hypercalls use architecture specific -- To unsubscribe from this list: send the line "unsubscribe linux-doc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html