2017-05-20 19:24 GMT+08:00 Jan H. Schönherr <jschoenh@xxxxxxxxx>: > Intel SDM says, that at most one LAPIC should be configured with ExtINT > delivery. KVM configures all LAPICs this way. This causes pic_unlock() > to kick the first available vCPU from the internal KVM data structures. > If this vCPU is not the BSP, but some not-yet-booted AP, the BSP may > never realize that there is an interrupt. > > Fix that by enabling ExtINT delivery only for the BSP. > > This allows booting a Linux guest without a TSC in the above situation. > Otherwise the BSP gets stuck in calibrate_delay_converge(). > > Signed-off-by: Jan H. Schönherr <jschoenh@xxxxxxxxx> Reviewed-by: Wanpeng Li <wanpeng.li@xxxxxxxxxxx> > --- > arch/x86/kvm/lapic.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c > index c329d28..df1b865 100644 > --- a/arch/x86/kvm/lapic.c > +++ b/arch/x86/kvm/lapic.c > @@ -1934,7 +1934,8 @@ void kvm_lapic_reset(struct kvm_vcpu *vcpu, bool init_event) > for (i = 0; i < KVM_APIC_LVT_NUM; i++) > kvm_lapic_set_reg(apic, APIC_LVTT + 0x10 * i, APIC_LVT_MASKED); > apic_update_lvtt(apic); > - if (kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_LINT0_REENABLED)) > + if (kvm_vcpu_is_reset_bsp(vcpu) && > + kvm_check_has_quirk(vcpu->kvm, KVM_X86_QUIRK_LINT0_REENABLED)) > kvm_lapic_set_reg(apic, APIC_LVT0, > SET_APIC_DELIVERY_MODE(0, APIC_MODE_EXTINT)); > apic_manage_nmi_watchdog(apic, kvm_lapic_get_reg(apic, APIC_LVT0)); > -- > 2.3.1.dirty >
