KVM: VMX: Add the deliver posted interrupt algorithm

Only deliver the posted interrupt when target vcpu is running
and there is no previous interrupt pending in pir.

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, 83 insertions, 1 deletions

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index d197579435d0..dbf74c922aa1 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -318,6 +318,19 @@ static u8 count_vectors(void *bitmap)
         return count;
 }
 
+void kvm_apic_update_irr(struct kvm_vcpu *vcpu, u32 *pir)
+{
+        u32 i, pir_val;
+        struct kvm_lapic *apic = vcpu->arch.apic;
+
+        for (i = 0; i <= 7; i++) {
+                pir_val = xchg(&pir[i], 0);
+                if (pir_val)
+                        *((u32 *)(apic->regs + APIC_IRR + i * 0x10)) |= pir_val;
+        }
+}
+EXPORT_SYMBOL_GPL(kvm_apic_update_irr);
+
 static inline int apic_test_and_set_irr(int vec, struct kvm_lapic *apic)
 {
         apic->irr_pending = true;
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index 7fe0c9180ea1..c730ac9fe801 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -54,6 +54,7 @@ u64 kvm_lapic_get_base(struct kvm_vcpu *vcpu);
 void kvm_apic_set_version(struct kvm_vcpu *vcpu);
 
 void kvm_apic_update_tmr(struct kvm_vcpu *vcpu, u32 *tmr);
+void kvm_apic_update_irr(struct kvm_vcpu *vcpu, u32 *pir);
 int kvm_apic_match_physical_addr(struct kvm_lapic *apic, u16 dest);
 int kvm_apic_match_logical_addr(struct kvm_lapic *apic, u8 mda);
 int kvm_apic_set_irq(struct kvm_vcpu *vcpu, struct kvm_lapic_irq *irq,
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 2f8fe3f06837..d6713e18bbc1 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3577,6 +3577,11 @@ static void svm_hwapic_isr_update(struct kvm *kvm, int isr)
         return;
 }
 
+static void svm_sync_pir_to_irr(struct kvm_vcpu *vcpu)
+{
+        return;
+}
+
 static int svm_nmi_allowed(struct kvm_vcpu *vcpu)
 {
         struct vcpu_svm *svm = to_svm(vcpu);
@@ -4305,6 +4310,7 @@ static struct kvm_x86_ops svm_x86_ops = {
         .vm_has_apicv = svm_vm_has_apicv,
         .load_eoi_exitmap = svm_load_eoi_exitmap,
         .hwapic_isr_update = svm_hwapic_isr_update,
+        .sync_pir_to_irr = svm_sync_pir_to_irr,
 
         .set_tss_addr = svm_set_tss_addr,
         .get_tdp_level = get_npt_level,
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 8535519d0352..3a14d8a0ee46 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -375,6 +375,23 @@ struct pi_desc {
         u32 rsvd[7];
 } __aligned(64);
 
+static bool pi_test_and_set_on(struct pi_desc *pi_desc)
+{
+        return test_and_set_bit(POSTED_INTR_ON,
+                        (unsigned long *)&pi_desc->control);
+}
+
+static bool pi_test_and_clear_on(struct pi_desc *pi_desc)
+{
+        return test_and_clear_bit(POSTED_INTR_ON,
+                        (unsigned long *)&pi_desc->control);
+}
+
+static int pi_test_and_set_pir(int vector, struct pi_desc *pi_desc)
+{
+        return test_and_set_bit(vector, (unsigned long *)pi_desc->pir);
+}
+
 struct vcpu_vmx {
         struct kvm_vcpu       vcpu;
         unsigned long         host_rsp;
@@ -639,6 +656,7 @@ static void vmx_get_segment(struct kvm_vcpu *vcpu,
                             struct kvm_segment *var, int seg);
 static bool guest_state_valid(struct kvm_vcpu *vcpu);
 static u32 vmx_segment_access_rights(struct kvm_segment *var);
+static void vmx_sync_pir_to_irr_dummy(struct kvm_vcpu *vcpu);
 
 static DEFINE_PER_CPU(struct vmcs *, vmxarea);
 static DEFINE_PER_CPU(struct vmcs *, current_vmcs);
@@ -2846,8 +2864,11 @@ static __init int hardware_setup(void)
 
         if (enable_apicv)
                 kvm_x86_ops->update_cr8_intercept = NULL;
-        else
+        else {
                 kvm_x86_ops->hwapic_irr_update = NULL;
+                kvm_x86_ops->deliver_posted_interrupt = NULL;
+                kvm_x86_ops->sync_pir_to_irr = vmx_sync_pir_to_irr_dummy;
+        }
 
         if (nested)
                 nested_vmx_setup_ctls_msrs();
@@ -3909,6 +3930,45 @@ static int vmx_vm_has_apicv(struct kvm *kvm)
 }
 
 /*
+ * Send interrupt to vcpu via posted interrupt way.
+ * 1. If target vcpu is running(non-root mode), send posted interrupt
+ * notification to vcpu and hardware will sync PIR to vIRR atomically.
+ * 2. If target vcpu isn't running(root mode), kick it to pick up the
+ * interrupt from PIR in next vmentry.
+ */
+static void vmx_deliver_posted_interrupt(struct kvm_vcpu *vcpu, int vector)
+{
+        struct vcpu_vmx *vmx = to_vmx(vcpu);
+        int r;
+
+        if (pi_test_and_set_pir(vector, &vmx->pi_desc))
+                return;
+
+        r = pi_test_and_set_on(&vmx->pi_desc);
+        kvm_make_request(KVM_REQ_EVENT, vcpu);
+        if (!r && (vcpu->mode == IN_GUEST_MODE))
+                apic->send_IPI_mask(get_cpu_mask(vcpu->cpu),
+                                POSTED_INTR_VECTOR);
+        else
+                kvm_vcpu_kick(vcpu);
+}
+
+static void vmx_sync_pir_to_irr(struct kvm_vcpu *vcpu)
+{
+        struct vcpu_vmx *vmx = to_vmx(vcpu);
+
+        if (!pi_test_and_clear_on(&vmx->pi_desc))
+                return;
+
+        kvm_apic_update_irr(vcpu, vmx->pi_desc.pir);
+}
+
+static void vmx_sync_pir_to_irr_dummy(struct kvm_vcpu *vcpu)
+{
+        return;
+}
+
+/*
  * Set up the vmcs's constant host-state fields, i.e., host-state fields that
  * will not change in the lifetime of the guest.
  * Note that host-state that does change is set elsewhere. E.g., host-state
@@ -7784,6 +7844,8 @@ static struct kvm_x86_ops vmx_x86_ops = {
         .load_eoi_exitmap = vmx_load_eoi_exitmap,
         .hwapic_irr_update = vmx_hwapic_irr_update,
         .hwapic_isr_update = vmx_hwapic_isr_update,
+        .sync_pir_to_irr = vmx_sync_pir_to_irr,
+        .deliver_posted_interrupt = vmx_deliver_posted_interrupt,
 
         .set_tss_addr = vmx_set_tss_addr,
         .get_tdp_level = get_ept_level,