x86, apicv: add APICv register virtualization support
- APIC read doesn't cause VM-Exit
- APIC write becomes trap-like
Reviewed-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Kevin Tian <kevin.tian@intel.com>
Signed-off-by: Yang Zhang <yang.z.zhang@intel.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index 9392f52..0664c13 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -1212,6 +1212,21 @@
}
EXPORT_SYMBOL_GPL(kvm_lapic_set_eoi);
+/* emulate APIC access in a trap manner */
+void kvm_apic_write_nodecode(struct kvm_vcpu *vcpu, u32 offset)
+{
+ u32 val = 0;
+
+ /* hw has done the conditional check and inst decode */
+ offset &= 0xff0;
+
+ apic_reg_read(vcpu->arch.apic, offset, 4, &val);
+
+ /* TODO: optimize to just emulate side effect w/o one more write */
+ apic_reg_write(vcpu->arch.apic, offset, val);
+}
+EXPORT_SYMBOL_GPL(kvm_apic_write_nodecode);
+
void kvm_free_lapic(struct kvm_vcpu *vcpu)
{
struct kvm_lapic *apic = vcpu->arch.apic;