KVM: nSVM: Drop pointless pdptrs_changed() check on nested transition

Remove the "PDPTRs unchanged" check to skip PDPTR loading during nested
SVM transitions as it's not at all an optimization.  Reading guest memory
to get the PDPTRs isn't magically cheaper by doing it in pdptrs_changed(),
and if the PDPTRs did change, KVM will end up doing the read twice.

Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210607090203.133058-3-mlevitsk@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/svm/nested.c

@@ -391,10 +391,8 @@ static int nested_svm_load_cr3(struct kvm_vcpu *vcpu, unsigned long cr3,
 		return -EINVAL;
 
 	if (!nested_npt && is_pae_paging(vcpu) &&
-	    (cr3 != kvm_read_cr3(vcpu) || pdptrs_changed(vcpu))) {
-		if (CC(!load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)))
-			return -EINVAL;
-	}
+	    CC(!load_pdptrs(vcpu, vcpu->arch.walk_mmu, cr3)))
+		return -EINVAL;
 
 	/*
 	 * TODO: optimize unconditional TLB flush/MMU sync here and in