From 52b5419016997f2960e9c8b6584c4acb3875d126 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Jan=20H=2E=20Sch=C3=B6nherr?= <jschoenh@amazon.de> Date: Sat, 20 May 2017 13:24:32 +0200 Subject: [PATCH] KVM: x86: Fix virtual wire mode MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit 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@amazon.de> Reviewed-by: Wanpeng Li <wanpeng.li@hotmail.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> --- 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 6e6f345adfe6a..d24c8742d9b0a 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -1936,7 +1936,8 @@ 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)); -- 2.30.2