diff --git a/src/asahi/genxml/cmdbuf.xml b/src/asahi/genxml/cmdbuf.xml
index 7496c60e050..62d6e028cc7 100644
--- a/src/asahi/genxml/cmdbuf.xml
+++ b/src/asahi/genxml/cmdbuf.xml
@@ -1127,7 +1127,7 @@
     <field name="S Resolve" start="58" size="1" type="bool"/>
   </struct>
 
-  <struct name="IOGPU Header" size="64">
+  <struct name="IOGPU Header" size="64" os="darwin">
     <field name="Unk 0" start="0:0" size="32" default="0x10000" type="hex"/>
     <field name="Total size" start="1:0" size="32" type="uint"/>
     <!-- 0x7 in 11.x -->
@@ -1140,7 +1140,7 @@
     <field name="Encoder" start="14:0" size="64" type="address"/>
   </struct>
 
-  <struct name="Spill Buffer Histogram" size="60">
+  <struct name="Spill Buffer Histogram" size="60" os="darwin">
     <field name="Bin 0" start="0:0" size="4" type="uint"/>
     <field name="Bin 1" start="1:0" size="4" type="uint"/>
     <field name="Bin 2" start="2:0" size="4" type="uint"/>
@@ -1158,7 +1158,7 @@
     <field name="Bin 14" start="14:0" size="4" type="uint"/>
   </struct>
 
-  <struct name="IOGPU Compute" size="384">
+  <struct name="IOGPU Compute" size="384" os="darwin">
     <field name="Deflake 1" start="20:0" size="64" type="address"/>
     <field name="Terminate of encoder" start="22:0" size="64" type="address"/>
     <field name="Deflake 2" start="26:0" size="64" type="address"/>
@@ -1185,7 +1185,7 @@
     <field name="Unk 95" start="95:0" size="32" default="0xffffffff" type="hex"/>
   </struct>
 
-  <struct name="IOGPU Graphics" size="1920">
+  <struct name="IOGPU Graphics" size="1920" os="darwin">
     <!-- if either deflake address is null, rendering gets flaky for high
          geometry counts -->
     <field name="Deflake 1" start="22:0" size="64" type="address"/>
@@ -1302,7 +1302,7 @@
     <field name="Unk 70:0" start="410:0" size="32" default="1" type="uint"/>
   </struct>
 
-  <struct name="IOGPU Attachment Count" size="16">
+  <struct name="IOGPU Attachment Count" size="16" os="darwin">
     <field name="Count" start="3:0" size="32" type="uint"/>
   </struct>
 
diff --git a/src/asahi/genxml/gen_pack.py b/src/asahi/genxml/gen_pack.py
index 911cc5d188f..d5f45eff119 100644
--- a/src/asahi/genxml/gen_pack.py
+++ b/src/asahi/genxml/gen_pack.py
@@ -9,6 +9,7 @@ import xml.parsers.expat
 import sys
 import operator
 import math
+import platform
 from functools import reduce
 
 global_prefix = "agx"
@@ -449,6 +450,7 @@ class Parser(object):
         self.parser = xml.parsers.expat.ParserCreate()
         self.parser.StartElementHandler = self.start_element
         self.parser.EndElementHandler = self.end_element
+        self.os = platform.system().lower()
 
         self.struct = None
         self.structs = {}
@@ -459,6 +461,9 @@ class Parser(object):
         return f'{global_prefix.upper()}_{name}'
 
     def start_element(self, name, attrs):
+        if "os" in attrs and attrs["os"] != self.os:
+            return
+
         if name == "genxml":
             print(pack_header)
         elif name == "struct":
@@ -471,7 +476,7 @@ class Parser(object):
                 self.group.length = int(attrs["size"])
             self.group.align = int(attrs["align"]) if "align" in attrs else None
             self.structs[attrs["name"]] = self.group
-        elif name == "field":
+        elif name == "field" and self.group is not None:
             self.group.fields.append(Field(self, attrs))
             self.values = []
         elif name == "enum":
@@ -487,10 +492,12 @@ class Parser(object):
 
     def end_element(self, name):
         if name == "struct":
-            self.emit_struct()
-            self.struct = None
+            if self.struct is not None:
+                self.emit_struct()
+                self.struct = None
+
             self.group = None
-        elif name  == "field":
+        elif name  == "field" and self.group is not None:
             self.group.fields[-1].values = self.values
         elif name  == "enum":
             self.emit_enum()