KVM: VMX: Mark VCPU_EXREG_PDPTR available in ept_save_pdptrs()

mmu->pdptrs[] and vmcs.GUEST_PDPTR[0-3] are synced, so mmu->pdptrs is
available and GUEST_PDPTR[0-3] is not dirty.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
Message-Id: <20211108124407.12187-3-jiangshanlai@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/vmx/vmx.c

@@ -2989,7 +2989,7 @@ void ept_save_pdptrs(struct kvm_vcpu *vcpu)
 	mmu->pdptrs[2] = vmcs_read64(GUEST_PDPTR2);
 	mmu->pdptrs[3] = vmcs_read64(GUEST_PDPTR3);
 
-	kvm_register_mark_dirty(vcpu, VCPU_EXREG_PDPTR);
+	kvm_register_mark_available(vcpu, VCPU_EXREG_PDPTR);
 }
 
 #define CR3_EXITING_BITS (CPU_BASED_CR3_LOAD_EXITING | \