KVM: do not treat noslot pfn as a error pfn

This patch filters noslot pfn out from error pfns based on Marcelo comment:
noslot pfn is not a error pfn

After this patch,
- is_noslot_pfn indicates that the gfn is not in slot
- is_error_pfn indicates that the gfn is in slot but the error is occurred
  when translate the gfn to pfn
- is_error_noslot_pfn indicates that the pfn either it is error pfns or it
  is noslot pfn
And is_invalid_pfn can be removed, it makes the code more clean

Signed-off-by: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>

arch/x86/kvm/mmu.c

@@ -2699,7 +2699,7 @@ static void transparent_hugepage_adjust(struct kvm_vcpu *vcpu,
 	 * PT_PAGE_TABLE_LEVEL and there would be no adjustment done
 	 * here.
 	 */
-	if (!is_error_pfn(pfn) && !kvm_is_mmio_pfn(pfn) &&
+	if (!is_error_noslot_pfn(pfn) && !kvm_is_mmio_pfn(pfn) &&
 	    level == PT_PAGE_TABLE_LEVEL &&
 	    PageTransCompound(pfn_to_page(pfn)) &&
 	    !has_wrprotected_page(vcpu->kvm, gfn, PT_DIRECTORY_LEVEL)) {
@@ -2733,7 +2733,7 @@ static bool handle_abnormal_pfn(struct kvm_vcpu *vcpu, gva_t gva, gfn_t gfn,
 	bool ret = true;
 
 	/* The pfn is invalid, report the error! */
-	if (unlikely(is_invalid_pfn(pfn))) {
+	if (unlikely(is_error_pfn(pfn))) {
 		*ret_val = kvm_handle_bad_page(vcpu, gfn, pfn);
 		goto exit;
 	}