Commit f4ef1910 authored Aug 01, 2017 by Wanpeng Li Committed by Radim Krčmář Aug 02, 2017

KVM: X86: Fix loss of pending INIT due to race



When SMP VM start, AP may lost INIT because of receiving INIT between
kvm_vcpu_ioctl_x86_get/set_vcpu_events.

       vcpu 0                             vcpu 1
                                   kvm_vcpu_ioctl_x86_get_vcpu_events
                                     events->smi.latched_init = 0
  send INIT to vcpu1
    set vcpu1's pending_events
                                   kvm_vcpu_ioctl_x86_set_vcpu_events
                                      if (events->smi.latched_init == 0)
                                        clear INIT in pending_events

This patch fixes it by just update SMM related flags if we are in SMM.

Thanks Peng Hao for the report and original commit message.

Reported-by: Peng Hao <peng.hao2@zte.com.cn>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>

parent 337c017c

arch/x86/kvm/x86.c

+11 −8

Original line number	Diff line number	Diff line
		@@ -3159,6 +3159,8 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu,
		kvm_set_hflags(vcpu, hflags);

		vcpu->arch.smi_pending = events->smi.pending;

		if (events->smi.smm) {
		if (events->smi.smm_inside_nmi)
		vcpu->arch.hflags \|= HF_SMM_INSIDE_NMI_MASK;
		else
		@@ -3170,6 +3172,7 @@ static int kvm_vcpu_ioctl_x86_set_vcpu_events(struct kvm_vcpu *vcpu,
		clear_bit(KVM_APIC_INIT, &vcpu->arch.apic->pending_events);
		}
		}
		}

		kvm_make_request(KVM_REQ_EVENT, vcpu);

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