x86/speculation/l1tf: Invert all not present mappings

Andi Kleen · KAGA-KOKO · commit f22cc87f6c1f · 2018-08-08T09:23:43.000+02:00
For kernel mappings PAGE_PROTNONE is not necessarily set for a non present
mapping, but the inversion logic explicitely checks for !PRESENT and
PROT_NONE.

Remove the PROT_NONE check and make the inversion unconditional for all not
present mappings.

Signed-off-by: Andi Kleen &lt;ak@linux.intel.com&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
diff --git a/arch/x86/include/asm/pgtable-invert.h b/arch/x86/include/asm/pgtable-invert.h
@@ -6,7 +6,7 @@
 
 static inline bool __pte_needs_invert(u64 val)
 {
-	return (val & (_PAGE_PRESENT|_PAGE_PROTNONE)) == _PAGE_PROTNONE;
+	return !(val & _PAGE_PRESENT);
 }
 
 /* Get a mask to xor with the page table entry to get the correct pfn. */

Original file line number	Diff line number	Diff line change
`@@ -6,7 +6,7 @@`
`6`	`6`
`7`	`7`	`static inline bool __pte_needs_invert(u64 val)`
`8`	`8`	`{`
`9`		`- return (val & (_PAGE_PRESENT\|_PAGE_PROTNONE)) == _PAGE_PROTNONE;`
	`9`	`+ return !(val & _PAGE_PRESENT);`
`10`	`10`	`}`
`11`	`11`
`12`	`12`	`/* Get a mask to xor with the page table entry to get the correct pfn. */`