KVM: Add reset/restore rtc_status support

restore rtc_status from migration or save/restore

Signed-off-by: Yang Zhang <yang.z.zhang@Intel.com>
Reviewed-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

4 files changed, 70 insertions, 0 deletions

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 0b734025fc87..67962188c775 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -94,6 +94,14 @@ static inline int apic_test_vector(int vec, void *bitmap)
         return test_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
 }
 
+bool kvm_apic_pending_eoi(struct kvm_vcpu *vcpu, int vector)
+{
+        struct kvm_lapic *apic = vcpu->arch.apic;
+
+        return apic_test_vector(vector, apic->regs + APIC_ISR) ||
+                apic_test_vector(vector, apic->regs + APIC_IRR);
+}
+
 static inline void apic_set_vector(int vec, void *bitmap)
 {
         set_bit(VEC_POS(vec), (bitmap) + REG_POS(vec));
@@ -1618,6 +1626,7 @@ void kvm_apic_post_state_restore(struct kvm_vcpu *vcpu,
         apic->highest_isr_cache = -1;
         kvm_x86_ops->hwapic_isr_update(vcpu->kvm, apic_find_highest_isr(apic));
         kvm_make_request(KVM_REQ_EVENT, vcpu);
+        kvm_rtc_eoi_tracking_restore_one(vcpu);
 }
 
 void __kvm_migrate_apic_timer(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index 3e5a43160cb7..16304b1a8cba 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -166,4 +166,6 @@ static inline bool kvm_apic_has_events(struct kvm_vcpu *vcpu)
         return vcpu->arch.apic->pending_events;
 }
 
+bool kvm_apic_pending_eoi(struct kvm_vcpu *vcpu, int vector);
+
 #endif
diff --git a/virt/kvm/ioapic.c b/virt/kvm/ioapic.c
index 27ae8dd64e29..9d76baa78e89 100644
--- a/virt/kvm/ioapic.c
+++ b/virt/kvm/ioapic.c
@@ -90,6 +90,62 @@ static unsigned long ioapic_read_indirect(struct kvm_ioapic *ioapic,
         return result;
 }
 
+static void rtc_irq_eoi_tracking_reset(struct kvm_ioapic *ioapic)
+{
+        ioapic->rtc_status.pending_eoi = 0;
+        bitmap_zero(ioapic->rtc_status.dest_map, KVM_MAX_VCPUS);
+}
+
+static void __rtc_irq_eoi_tracking_restore_one(struct kvm_vcpu *vcpu)
+{
+        bool new_val, old_val;
+        struct kvm_ioapic *ioapic = vcpu->kvm->arch.vioapic;
+        union kvm_ioapic_redirect_entry *e;
+
+        e = &ioapic->redirtbl[RTC_GSI];
+        if (!kvm_apic_match_dest(vcpu, NULL, 0, e->fields.dest_id,
+                                e->fields.dest_mode))
+                return;
+
+        new_val = kvm_apic_pending_eoi(vcpu, e->fields.vector);
+        old_val = test_bit(vcpu->vcpu_id, ioapic->rtc_status.dest_map);
+
+        if (new_val == old_val)
+                return;
+
+        if (new_val) {
+                __set_bit(vcpu->vcpu_id, ioapic->rtc_status.dest_map);
+                ioapic->rtc_status.pending_eoi++;
+        } else {
+                __clear_bit(vcpu->vcpu_id, ioapic->rtc_status.dest_map);
+                ioapic->rtc_status.pending_eoi--;
+        }
+
+        WARN_ON(ioapic->rtc_status.pending_eoi < 0);
+}
+
+void kvm_rtc_eoi_tracking_restore_one(struct kvm_vcpu *vcpu)
+{
+        struct kvm_ioapic *ioapic = vcpu->kvm->arch.vioapic;
+
+        spin_lock(&ioapic->lock);
+        __rtc_irq_eoi_tracking_restore_one(vcpu);
+        spin_unlock(&ioapic->lock);
+}
+
+static void kvm_rtc_eoi_tracking_restore_all(struct kvm_ioapic *ioapic)
+{
+        struct kvm_vcpu *vcpu;
+        int i;
+
+        if (RTC_GSI >= IOAPIC_NUM_PINS)
+                return;
+
+        rtc_irq_eoi_tracking_reset(ioapic);
+        kvm_for_each_vcpu(i, vcpu, ioapic->kvm)
+            __rtc_irq_eoi_tracking_restore_one(vcpu);
+}
+
 static int ioapic_service(struct kvm_ioapic *ioapic, unsigned int idx)
 {
         union kvm_ioapic_redirect_entry *pent;
@@ -428,6 +484,7 @@ void kvm_ioapic_reset(struct kvm_ioapic *ioapic)
         ioapic->ioregsel = 0;
         ioapic->irr = 0;
         ioapic->id = 0;
+        rtc_irq_eoi_tracking_reset(ioapic);
         update_handled_vectors(ioapic);
 }
 
@@ -494,6 +551,7 @@ int kvm_set_ioapic(struct kvm *kvm, struct kvm_ioapic_state *state)
         memcpy(ioapic, state, sizeof(struct kvm_ioapic_state));
         update_handled_vectors(ioapic);
         kvm_ioapic_make_eoibitmap_request(kvm);
+        kvm_rtc_eoi_tracking_restore_all(ioapic);
         spin_unlock(&ioapic->lock);
         return 0;
 }
diff --git a/virt/kvm/ioapic.h b/virt/kvm/ioapic.h
index 761e5b57099e..313fc4ea61d9 100644
--- a/virt/kvm/ioapic.h
+++ b/virt/kvm/ioapic.h
@@ -79,6 +79,7 @@ static inline struct kvm_ioapic *ioapic_irqchip(struct kvm *kvm)
         return kvm->arch.vioapic;
 }
 
+void kvm_rtc_eoi_tracking_restore_one(struct kvm_vcpu *vcpu);
 int kvm_apic_match_dest(struct kvm_vcpu *vcpu, struct kvm_lapic *source,
                 int short_hand, int dest, int dest_mode);
 int kvm_apic_compare_prio(struct kvm_vcpu *vcpu1, struct kvm_vcpu *vcpu2);