commit 59fd132340b3e37b83179d2fcb673980035edf62
author Radim Krčmář <rkrcmar@redhat.com> Tue Jun 30 22:19:16 2015 +0200
committer Paolo Bonzini <pbonzini@redhat.com> Fri Jul 03 18:55:18 2015 +0200
tree 205f62686d47c95eb3c4dbbc2b3d48b42b26510d
parent db1385624c686fe99fe2d1b61a36e1537b915d08

KVM: x86: keep track of LVT0 changes under APICv

Memory-mapped LVT0 register already contains the new value when APICv
traps so we can't directly detect a change.
Memorize a bit we are interested in to enable legacy NMI watchdog.

Suggested-by: Yoshida Nobuo <yoshida.nb@ncos.nec.co.jp>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/lapic.c

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index e0f721b..954e98a 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1257,16 +1257,17 @@
 
 static void apic_manage_nmi_watchdog(struct kvm_lapic *apic, u32 lvt0_val)
 {
-	int nmi_wd_enabled = apic_lvt_nmi_mode(kvm_apic_get_reg(apic, APIC_LVT0));
+	bool lvt0_in_nmi_mode = apic_lvt_nmi_mode(lvt0_val);
 
-	if (apic_lvt_nmi_mode(lvt0_val)) {
-		if (!nmi_wd_enabled) {
+	if (apic->lvt0_in_nmi_mode != lvt0_in_nmi_mode) {
+		apic->lvt0_in_nmi_mode = lvt0_in_nmi_mode;
+		if (lvt0_in_nmi_mode) {
 			apic_debug("Receive NMI setting on APIC_LVT0 "
 				   "for cpu %d\n", apic->vcpu->vcpu_id);
 			atomic_inc(&apic->vcpu->kvm->arch.vapics_in_nmi_mode);
-		}
-	} else if (nmi_wd_enabled)
-		atomic_dec(&apic->vcpu->kvm->arch.vapics_in_nmi_mode);
+		} else
+			atomic_dec(&apic->vcpu->kvm->arch.vapics_in_nmi_mode);
+	}
 }
 
 static int apic_reg_write(struct kvm_lapic *apic, u32 reg, u32 val)
@@ -1597,6 +1598,7 @@
 	if (!(vcpu->kvm->arch.disabled_quirks & KVM_QUIRK_LINT0_REENABLED))
 		apic_set_reg(apic, APIC_LVT0,
 			     SET_APIC_DELIVERY_MODE(0, APIC_MODE_EXTINT));
+	apic_manage_nmi_watchdog(apic, kvm_apic_get_reg(apic, APIC_LVT0));
 
 	apic_set_reg(apic, APIC_DFR, 0xffffffffU);
 	apic_set_spiv(apic, 0xff);