Virtual interrupt delivery avoids KVM to inject vAPIC interrupts
manually, which is fully taken care of by the hardware. This needs
some special awareness into existing interrupr injection path:
- for pending interrupt, instead of direct injection, we may need
update architecture specific indicators before resuming to guest.
- A pending interrupt, which is masked by ISR, should be also
considered in above update action, since hardware will decide
when to inject it at right time. Current has_interrupt and
get_interrupt only returns a valid vector from injection p.o.v.
Three new interfaces are introduced accordingly:
kvm_apic_get_highest_irr
kvm_cpu_has_interrupt_apicv_vid
kvm_cpu_get_interrupt_apic_vid
Signed-off-by: Kevin Tian <kevin.tian@xxxxxxxxx>
Signed-off-by: Jiongxi Li <jiongxi.li@xxxxxxxxx>
---
arch/x86/include/asm/kvm_host.h | 2 +
arch/x86/kvm/irq.c | 44 +++++++++++++++++++++++++++++++++++++++
arch/x86/kvm/lapic.c | 13 +++++++++++
arch/x86/kvm/lapic.h | 10 ++++++++
arch/x86/kvm/svm.c | 6 +++++
arch/x86/kvm/vmx.c | 6 +++++
arch/x86/kvm/x86.c | 22 +++++++++++++++++-
7 files changed, 101 insertions(+), 2 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 09155d6..ef74df5 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -669,6 +669,8 @@ struct kvm_x86_ops {
void (*enable_nmi_window)(struct kvm_vcpu *vcpu);
void (*enable_irq_window)(struct kvm_vcpu *vcpu);
void (*update_cr8_intercept)(struct kvm_vcpu *vcpu, int tpr, int irr);
+ int (*has_virtual_interrupt_delivery)(struct kvm_vcpu *vcpu);
+ void (*update_irq)(struct kvm_vcpu *vcpu);
int (*set_tss_addr)(struct kvm *kvm, unsigned int addr);
int (*get_tdp_level)(void);
u64 (*get_mt_mask)(struct kvm_vcpu *vcpu, gfn_t gfn, bool is_mmio);
diff --git a/arch/x86/kvm/irq.c b/arch/x86/kvm/irq.c
index 7e06ba1..abd3831 100644
--- a/arch/x86/kvm/irq.c
+++ b/arch/x86/kvm/irq.c
@@ -60,6 +60,29 @@ int kvm_cpu_has_interrupt(struct kvm_vcpu *v)
EXPORT_SYMBOL_GPL(kvm_cpu_has_interrupt);
/*
+ * check if there is pending interrupt without
+ * intack. This _apicv version is used when hardware
+ * supports APIC virtualization with virtual interrupt
+ * delivery support. In such case, KVM is not required
+ * to poll pending APIC interrupt, and thus this
+ * interface is used to poll pending interupts from
+ * non-APIC source.
+ */
+int kvm_cpu_has_interrupt_apic_vid(struct kvm_vcpu *v)
+{
+ struct kvm_pic *s;
+
+ if (!irqchip_in_kernel(v->kvm))
+ return v->arch.interrupt.pending;
+
+ if (kvm_apic_accept_pic_intr(v)) {
+ s = pic_irqchip(v->kvm); /* PIC */
+ return s->output;
+ } else
+ return 0;
+}
+
+/*
* Read pending interrupt vector and intack.
*/
int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
@@ -82,6 +105,27 @@ int kvm_cpu_get_interrupt(struct kvm_vcpu *v)
}
EXPORT_SYMBOL_GPL(kvm_cpu_get_interrupt);
+/*
+ * Read pending interrupt vector and intack.
+ * Similar to kvm_cpu_has_interrupt_apicv, to get
+ * interrupts from non-APIC sources.
+ */
+int kvm_cpu_get_interrupt_apic_vid(struct kvm_vcpu *v)
+{
+ struct kvm_pic *s;
+ int vector = -1;
+
+ if (!irqchip_in_kernel(v->kvm))
+ return v->arch.interrupt.nr;
+
+ if (kvm_apic_accept_pic_intr(v)) {
+ s = pic_irqchip(v->kvm);
+ s->output = 0; /* PIC */
+ vector = kvm_pic_read_irq(v->kvm);
+ }
+ return vector;
+}
+
void kvm_inject_pending_timer_irqs(struct kvm_vcpu *vcpu)
{
kvm_inject_apic_timer_irqs(vcpu);
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 4a6d3a4..c47f3d3 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1310,6 +1310,8 @@ int kvm_create_lapic(struct kvm_vcpu *vcpu)
kvm_lapic_reset(vcpu);
kvm_iodevice_init(&apic->dev, &apic_mmio_ops);
+ if (kvm_x86_ops->has_virtual_interrupt_delivery(vcpu))
+ apic->vid_enabled = true;
return 0;
nomem_free_apic:
kfree(apic);
@@ -1333,6 +1335,17 @@ int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu)
return highest_irr;
}
+int kvm_apic_get_highest_irr(struct kvm_vcpu *vcpu)
+{
+ struct kvm_lapic *apic = vcpu->arch.apic;
+
+ if (!apic || !apic_enabled(apic))
+ return -1;
+
+ return apic_find_highest_irr(apic);
+}
+EXPORT_SYMBOL_GPL(kvm_apic_get_highest_irr);
+
int kvm_apic_accept_pic_intr(struct kvm_vcpu *vcpu)
{
u32 lvt0 = apic_get_reg(vcpu->arch.apic, APIC_LVT0);
diff --git a/arch/x86/kvm/lapic.h b/arch/x86/kvm/lapic.h
index cd4875e..4e3b435 100644
--- a/arch/x86/kvm/lapic.h
+++ b/arch/x86/kvm/lapic.h
@@ -13,6 +13,7 @@ struct kvm_lapic {
u32 divide_count;
struct kvm_vcpu *vcpu;
bool irr_pending;
+ bool vid_enabled;
/* Number of bits set in ISR. */
s16 isr_count;
/* The highest vector set in ISR; if -1 - invalid, must scan ISR. */
@@ -32,6 +33,9 @@ void kvm_free_lapic(struct kvm_vcpu *vcpu);
int kvm_apic_has_interrupt(struct kvm_vcpu *vcpu);
int kvm_apic_accept_pic_intr(struct kvm_vcpu *vcpu);
int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu);
+int kvm_cpu_has_interrupt_apic_vid(struct kvm_vcpu *v);
+int kvm_cpu_get_interrupt_apic_vid(struct kvm_vcpu *v);
+int kvm_apic_get_highest_irr(struct kvm_vcpu *vcpu);
void kvm_lapic_reset(struct kvm_vcpu *vcpu);
u64 kvm_lapic_get_cr8(struct kvm_vcpu *vcpu);
void kvm_lapic_set_tpr(struct kvm_vcpu *vcpu, unsigned long cr8);
@@ -72,5 +76,11 @@ static inline bool kvm_hv_vapic_assist_page_enabled(struct kvm_vcpu *vcpu)
return vcpu->arch.hv_vapic & HV_X64_MSR_APIC_ASSIST_PAGE_ENABLE;
}
+static inline bool kvm_apic_vid_enabled(struct kvm_vcpu *vcpu)
+{
+ struct kvm_lapic *apic = vcpu->arch.apic;
+ return apic->vid_enabled;
+}
+
int kvm_lapic_enable_pv_eoi(struct kvm_vcpu *vcpu, u64 data);
#endif
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index baead95..65a301a 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3580,6 +3580,11 @@ static void update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr)
set_cr_intercept(svm, INTERCEPT_CR8_WRITE);
}
+static int svm_has_virtual_interrupt_delivery(struct kvm_vcpu *vcpu)
+{
+ return 0;
+}
+
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 = {
.enable_nmi_window = enable_nmi_window,
.enable_irq_window = enable_irq_window,
.update_cr8_intercept = update_cr8_intercept,
+ .has_virtual_interrupt_delivery = svm_has_virtual_interrupt_delivery,
.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 3d92277..4a26d04 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -6080,6 +6080,11 @@ static void update_cr8_intercept(struct kvm_vcpu *vcpu, int tpr, int irr)
vmcs_write32(TPR_THRESHOLD, irr);
}
+static int vmx_has_virtual_interrupt_delivery(struct kvm_vcpu *vcpu)
+{
+ return 0;
+}
+
static void vmx_complete_atomic_exit(struct vcpu_vmx *vmx)
{
u32 exit_intr_info;
@@ -7339,6 +7344,7 @@ static struct kvm_x86_ops vmx_x86_ops = {
.enable_nmi_window = enable_nmi_window,
.enable_irq_window = enable_irq_window,
.update_cr8_intercept = update_cr8_intercept,
+ .has_virtual_interrupt_delivery = vmx_has_virtual_interrupt_delivery,
.set_tss_addr = vmx_set_tss_addr,
.get_tdp_level = get_ept_level,
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 148ed66..47ac609 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5194,6 +5194,13 @@ static void inject_pending_event(struct kvm_vcpu *vcpu)
vcpu->arch.nmi_injected = true;
kvm_x86_ops->set_nmi(vcpu);
}
+ } else if (kvm_apic_vid_enabled(vcpu)) {
+ if (kvm_cpu_has_interrupt_apic_vid(vcpu) &&
+ kvm_x86_ops->interrupt_allowed(vcpu)) {
+ kvm_queue_interrupt(vcpu,
+ kvm_cpu_get_interrupt_apic_vid(vcpu), false);
+ kvm_x86_ops->set_irq(vcpu);
+ }
} else if (kvm_cpu_has_interrupt(vcpu)) {
if (kvm_x86_ops->interrupt_allowed(vcpu)) {
kvm_queue_interrupt(vcpu, kvm_cpu_get_interrupt(vcpu),
@@ -5293,16 +5300,27 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
}
if (kvm_check_request(KVM_REQ_EVENT, vcpu) || req_int_win) {
+ /* update archtecture specific hints for APIC virtual interrupt delivery */
+ if (kvm_apic_vid_enabled(vcpu))
+ kvm_x86_ops->update_irq(vcpu);
+
inject_pending_event(vcpu);
/* enable NMI/IRQ window open exits if needed */
if (vcpu->arch.nmi_pending)
kvm_x86_ops->enable_nmi_window(vcpu);
- else if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
+ else if (kvm_apic_vid_enabled(vcpu)) {
+ if (kvm_cpu_has_interrupt_apic_vid(vcpu))
+ kvm_x86_ops->enable_irq_window(vcpu);
+ } else if (kvm_cpu_has_interrupt(vcpu) || req_int_win)
kvm_x86_ops->enable_irq_window(vcpu);
if (kvm_lapic_enabled(vcpu)) {
- update_cr8_intercept(vcpu);
+ /* no need for tpr_threshold update if APIC virtual
+ * interrupt delivery is enabled
+ */
+ if (!kvm_apic_vid_enabled(vcpu))
+ update_cr8_intercept(vcpu);
kvm_lapic_sync_to_vapic(vcpu);
}
}
--
1.7.1
--
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