KVM: x86: Split the APIC from the rest of IRQCHIP.
First patch in a series which enables the relocation of the
PIC/IOAPIC to userspace.
Adds capability KVM_CAP_SPLIT_IRQCHIP;
KVM_CAP_SPLIT_IRQCHIP enables the construction of LAPICs without the
rest of the irqchip.
Compile tested for x86.
Signed-off-by: Steve Rutherford <srutherford@google.com>
Suggested-by: Andrew Honig <ahonig@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 28c98c8..f720774 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -2448,6 +2448,7 @@
case KVM_CAP_ENABLE_CAP_VM:
case KVM_CAP_DISABLE_QUIRKS:
case KVM_CAP_SET_BOOT_CPU_ID:
+ case KVM_CAP_SPLIT_IRQCHIP:
#ifdef CONFIG_KVM_DEVICE_ASSIGNMENT
case KVM_CAP_ASSIGN_DEV_IRQ:
case KVM_CAP_PCI_2_3:
@@ -3555,6 +3556,24 @@
kvm->arch.disabled_quirks = cap->args[0];
r = 0;
break;
+ case KVM_CAP_SPLIT_IRQCHIP: {
+ mutex_lock(&kvm->lock);
+ r = -EEXIST;
+ if (irqchip_in_kernel(kvm))
+ goto split_irqchip_unlock;
+ if (atomic_read(&kvm->online_vcpus))
+ goto split_irqchip_unlock;
+ r = kvm_setup_empty_irq_routing(kvm);
+ if (r)
+ goto split_irqchip_unlock;
+ /* Pairs with irqchip_in_kernel. */
+ smp_wmb();
+ kvm->arch.irqchip_split = true;
+ r = 0;
+split_irqchip_unlock:
+ mutex_unlock(&kvm->lock);
+ break;
+ }
default:
r = -EINVAL;
break;
@@ -3668,7 +3687,7 @@
}
r = -ENXIO;
- if (!irqchip_in_kernel(kvm))
+ if (!irqchip_in_kernel(kvm) || irqchip_split(kvm))
goto get_irqchip_out;
r = kvm_vm_ioctl_get_irqchip(kvm, chip);
if (r)
@@ -3692,7 +3711,7 @@
}
r = -ENXIO;
- if (!irqchip_in_kernel(kvm))
+ if (!irqchip_in_kernel(kvm) || irqchip_split(kvm))
goto set_irqchip_out;
r = kvm_vm_ioctl_set_irqchip(kvm, chip);
if (r)
