diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 9fcc2897b8..f7b961e04c 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -654,6 +654,7 @@ static Aml *aml_pci_pdsm(void)
     Aml *acpi_index = aml_local(2);
     Aml *zero = aml_int(0);
     Aml *one = aml_int(1);
+    Aml *not_supp = aml_int(0xFFFFFFFF);
     Aml *func = aml_arg(2);
     Aml *params = aml_arg(4);
     Aml *bnum = aml_derefof(aml_index(params, aml_int(0)));
@@ -678,7 +679,7 @@ static Aml *aml_pci_pdsm(void)
          */
         ifctx1 = aml_if(aml_lnot(
                      aml_or(aml_equal(acpi_index, zero),
-                            aml_equal(acpi_index, aml_int(0xFFFFFFFF)), NULL)
+                            aml_equal(acpi_index, not_supp), NULL)
                  ));
         {
             /* have supported functions */
@@ -704,18 +705,30 @@ static Aml *aml_pci_pdsm(void)
     {
        Aml *pkg = aml_package(2);
 
-       aml_append(pkg, zero);
-       /*
-        * optional, if not impl. should return null string
-        */
-       aml_append(pkg, aml_string("%s", ""));
-       aml_append(ifctx, aml_store(pkg, ret));
-
        aml_append(ifctx, aml_store(aml_call2("AIDX", bnum, sunum), acpi_index));
+       aml_append(ifctx, aml_store(pkg, ret));
        /*
-        * update acpi-index to actual value
+        * Windows calls func=7 without checking if it's available,
+        * as workaround Microsoft has suggested to return invalid for func7
+        * Package, so return 2 elements package but only initialize elements
+        * when acpi_index is supported and leave them uninitialized, which
+        * leads elements to being Uninitialized ObjectType and should trip
+        * Windows into discarding result as an unexpected and prevent setting
+        * bogus 'PCI Label' on the device.
         */
-       aml_append(ifctx, aml_store(acpi_index, aml_index(ret, zero)));
+       ifctx1 = aml_if(aml_lnot(aml_lor(
+                    aml_equal(acpi_index, zero), aml_equal(acpi_index, not_supp)
+                )));
+       {
+           aml_append(ifctx1, aml_store(acpi_index, aml_index(ret, zero)));
+           /*
+            * optional, if not impl. should return null string
+            */
+           aml_append(ifctx1, aml_store(aml_string("%s", ""),
+                                        aml_index(ret, one)));
+       }
+       aml_append(ifctx, ifctx1);
+
        aml_append(ifctx, aml_return(ret));
     }