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KVM: Fix leak vCPU's VMCS value into other pCPU
commit17e433b543
upstream. After commitd73eb57b80
(KVM: Boost vCPUs that are delivering interrupts), a five years old bug is exposed. Running ebizzy benchmark in three 80 vCPUs VMs on one 80 pCPUs Skylake server, a lot of rcu_sched stall warning splatting in the VMs after stress testing: INFO: rcu_sched detected stalls on CPUs/tasks: { 4 41 57 62 77} (detected by 15, t=60004 jiffies, g=899, c=898, q=15073) Call Trace: flush_tlb_mm_range+0x68/0x140 tlb_flush_mmu.part.75+0x37/0xe0 tlb_finish_mmu+0x55/0x60 zap_page_range+0x142/0x190 SyS_madvise+0x3cd/0x9c0 system_call_fastpath+0x1c/0x21 swait_active() sustains to be true before finish_swait() is called in kvm_vcpu_block(), voluntarily preempted vCPUs are taken into account by kvm_vcpu_on_spin() loop greatly increases the probability condition kvm_arch_vcpu_runnable(vcpu) is checked and can be true, when APICv is enabled the yield-candidate vCPU's VMCS RVI field leaks(by vmx_sync_pir_to_irr()) into spinning-on-a-taken-lock vCPU's current VMCS. This patch fixes it by checking conservatively a subset of events. Cc: Paolo Bonzini <pbonzini@redhat.com> Cc: Radim Krčmář <rkrcmar@redhat.com> Cc: Christian Borntraeger <borntraeger@de.ibm.com> Cc: Marc Zyngier <Marc.Zyngier@arm.com> Cc: stable@vger.kernel.org Fixes:98f4a1467
(KVM: add kvm_arch_vcpu_runnable() test to kvm_vcpu_on_spin() loop) Signed-off-by: Wanpeng Li <wanpengli@tencent.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
d1489f0b4d
commit
2bc73d9141
7 changed files with 59 additions and 1 deletions
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@ -61,6 +61,11 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *v)
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return !!(v->arch.pending_exceptions) || kvm_request_pending(v);
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}
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bool kvm_arch_dy_runnable(struct kvm_vcpu *vcpu)
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{
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return kvm_arch_vcpu_runnable(vcpu);
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}
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bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
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{
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return false;
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@ -1113,6 +1113,7 @@ struct kvm_x86_ops {
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int (*update_pi_irte)(struct kvm *kvm, unsigned int host_irq,
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uint32_t guest_irq, bool set);
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void (*apicv_post_state_restore)(struct kvm_vcpu *vcpu);
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bool (*dy_apicv_has_pending_interrupt)(struct kvm_vcpu *vcpu);
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int (*set_hv_timer)(struct kvm_vcpu *vcpu, u64 guest_deadline_tsc);
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void (*cancel_hv_timer)(struct kvm_vcpu *vcpu);
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@ -5146,6 +5146,11 @@ static void svm_deliver_avic_intr(struct kvm_vcpu *vcpu, int vec)
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kvm_vcpu_wake_up(vcpu);
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}
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static bool svm_dy_apicv_has_pending_interrupt(struct kvm_vcpu *vcpu)
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{
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return false;
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}
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static void svm_ir_list_del(struct vcpu_svm *svm, struct amd_iommu_pi_data *pi)
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{
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unsigned long flags;
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@ -7203,6 +7208,7 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
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.pmu_ops = &amd_pmu_ops,
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.deliver_posted_interrupt = svm_deliver_avic_intr,
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.dy_apicv_has_pending_interrupt = svm_dy_apicv_has_pending_interrupt,
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.update_pi_irte = svm_update_pi_irte,
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.setup_mce = svm_setup_mce,
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@ -10411,6 +10411,11 @@ static u8 vmx_has_apicv_interrupt(struct kvm_vcpu *vcpu)
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return ((rvi & 0xf0) > (vppr & 0xf0));
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}
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static bool vmx_dy_apicv_has_pending_interrupt(struct kvm_vcpu *vcpu)
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{
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return pi_test_on(vcpu_to_pi_desc(vcpu));
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}
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static void vmx_load_eoi_exitmap(struct kvm_vcpu *vcpu, u64 *eoi_exit_bitmap)
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{
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if (!kvm_vcpu_apicv_active(vcpu))
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@ -14387,6 +14392,7 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
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.guest_apic_has_interrupt = vmx_guest_apic_has_interrupt,
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.sync_pir_to_irr = vmx_sync_pir_to_irr,
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.deliver_posted_interrupt = vmx_deliver_posted_interrupt,
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.dy_apicv_has_pending_interrupt = vmx_dy_apicv_has_pending_interrupt,
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.set_tss_addr = vmx_set_tss_addr,
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.set_identity_map_addr = vmx_set_identity_map_addr,
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@ -9336,6 +9336,22 @@ int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
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return kvm_vcpu_running(vcpu) || kvm_vcpu_has_events(vcpu);
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}
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bool kvm_arch_dy_runnable(struct kvm_vcpu *vcpu)
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{
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if (READ_ONCE(vcpu->arch.pv.pv_unhalted))
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return true;
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if (kvm_test_request(KVM_REQ_NMI, vcpu) ||
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kvm_test_request(KVM_REQ_SMI, vcpu) ||
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kvm_test_request(KVM_REQ_EVENT, vcpu))
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return true;
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if (vcpu->arch.apicv_active && kvm_x86_ops->dy_apicv_has_pending_interrupt(vcpu))
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return true;
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return false;
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}
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bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu)
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{
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return vcpu->arch.preempted_in_kernel;
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@ -818,6 +818,7 @@ void kvm_arch_check_processor_compat(void *rtn);
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int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu);
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bool kvm_arch_vcpu_in_kernel(struct kvm_vcpu *vcpu);
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int kvm_arch_vcpu_should_kick(struct kvm_vcpu *vcpu);
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bool kvm_arch_dy_runnable(struct kvm_vcpu *vcpu);
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#ifndef __KVM_HAVE_ARCH_VM_ALLOC
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/*
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@ -2317,6 +2317,29 @@ static bool kvm_vcpu_eligible_for_directed_yield(struct kvm_vcpu *vcpu)
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#endif
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}
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/*
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* Unlike kvm_arch_vcpu_runnable, this function is called outside
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* a vcpu_load/vcpu_put pair. However, for most architectures
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* kvm_arch_vcpu_runnable does not require vcpu_load.
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*/
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bool __weak kvm_arch_dy_runnable(struct kvm_vcpu *vcpu)
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{
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return kvm_arch_vcpu_runnable(vcpu);
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}
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static bool vcpu_dy_runnable(struct kvm_vcpu *vcpu)
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{
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if (kvm_arch_dy_runnable(vcpu))
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return true;
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#ifdef CONFIG_KVM_ASYNC_PF
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if (!list_empty_careful(&vcpu->async_pf.done))
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return true;
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#endif
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return false;
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}
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void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode)
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{
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struct kvm *kvm = me->kvm;
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@ -2346,7 +2369,7 @@ void kvm_vcpu_on_spin(struct kvm_vcpu *me, bool yield_to_kernel_mode)
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continue;
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if (vcpu == me)
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continue;
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if (swait_active(&vcpu->wq) && !kvm_arch_vcpu_runnable(vcpu))
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if (swait_active(&vcpu->wq) && !vcpu_dy_runnable(vcpu))
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continue;
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if (yield_to_kernel_mode && !kvm_arch_vcpu_in_kernel(vcpu))
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continue;
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