KVM: Accelerated apic support
This adds a mechanism for exposing the virtual apic tpr to the guest, and a
protocol for letting the guest update the tpr without causing a vmexit if
conditions allow (e.g. there is no interrupt pending with a higher priority
than the new tpr).
Signed-off-by: Avi Kivity <avi@qumranet.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index c2b8088..e7eac27 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -1173,6 +1173,19 @@
r = 0;
break;
};
+ case KVM_SET_VAPIC_ADDR: {
+ struct kvm_vapic_addr va;
+
+ r = -EINVAL;
+ if (!irqchip_in_kernel(vcpu->kvm))
+ goto out;
+ r = -EFAULT;
+ if (copy_from_user(&va, argp, sizeof va))
+ goto out;
+ r = 0;
+ kvm_lapic_set_vapic_addr(vcpu, va.vapic_addr);
+ break;
+ }
default:
r = -EINVAL;
}
@@ -2214,6 +2227,9 @@
}
switch (nr) {
+ case KVM_HC_VAPIC_POLL_IRQ:
+ ret = 0;
+ break;
default:
ret = -KVM_ENOSYS;
break;
@@ -2421,6 +2437,29 @@
vcpu->arch.irq_summary == 0);
}
+static void vapic_enter(struct kvm_vcpu *vcpu)
+{
+ struct kvm_lapic *apic = vcpu->arch.apic;
+ struct page *page;
+
+ if (!apic || !apic->vapic_addr)
+ return;
+
+ page = gfn_to_page(vcpu->kvm, apic->vapic_addr >> PAGE_SHIFT);
+ vcpu->arch.apic->vapic_page = page;
+}
+
+static void vapic_exit(struct kvm_vcpu *vcpu)
+{
+ struct kvm_lapic *apic = vcpu->arch.apic;
+
+ if (!apic || !apic->vapic_addr)
+ return;
+
+ kvm_release_page_dirty(apic->vapic_page);
+ mark_page_dirty(vcpu->kvm, apic->vapic_addr >> PAGE_SHIFT);
+}
+
static int __vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
{
int r;
@@ -2435,6 +2474,8 @@
vcpu->arch.mp_state = VCPU_MP_STATE_RUNNABLE;
}
+ vapic_enter(vcpu);
+
preempted:
if (vcpu->guest_debug.enabled)
kvm_x86_ops->guest_debug_pre(vcpu);
@@ -2444,6 +2485,14 @@
if (unlikely(r))
goto out;
+ if (vcpu->requests)
+ if (test_and_clear_bit(KVM_REQ_REPORT_TPR_ACCESS,
+ &vcpu->requests)) {
+ kvm_run->exit_reason = KVM_EXIT_TPR_ACCESS;
+ r = 0;
+ goto out;
+ }
+
kvm_inject_pending_timer_irqs(vcpu);
preempt_disable();
@@ -2469,6 +2518,8 @@
else
kvm_x86_ops->inject_pending_vectors(vcpu, kvm_run);
+ kvm_lapic_sync_to_vapic(vcpu);
+
vcpu->guest_mode = 1;
kvm_guest_enter();
@@ -2506,6 +2557,8 @@
if (vcpu->arch.exception.pending && kvm_x86_ops->exception_injected(vcpu))
vcpu->arch.exception.pending = false;
+ kvm_lapic_sync_from_vapic(vcpu);
+
r = kvm_x86_ops->handle_exit(kvm_run, vcpu);
if (r > 0) {
@@ -2527,6 +2580,8 @@
post_kvm_run_save(vcpu, kvm_run);
+ vapic_exit(vcpu);
+
return r;
}