KVM: Cache pdptrs

Instead of reloading the pdptrs on every entry and exit (vmcs writes on vmx,
guest memory access on svm) extract them on demand.

Signed-off-by: Avi Kivity <avi@redhat.com>

arch/x86/include/asm/kvm_host.h

@@ -120,6 +120,10 @@ enum kvm_reg {
 	NR_VCPU_REGS
 };
 
+enum kvm_reg_ex {
+	VCPU_EXREG_PDPTR = NR_VCPU_REGS,
+};
+
 enum {
 	VCPU_SREG_ES,
 	VCPU_SREG_CS,