[PATCH 4.9 101/107] x86/speculation/l1tf: Invert all not present mappings

From: Greg Kroah-Hartman
Date: Tue Aug 14 2018 - 13:45:44 EST

4.9-stable review patch. If anyone has any objections, please let me know.


From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

commit f22cc87f6c1f771b57c407555cfefd811cdd9507 upstream

For kernel mappings PAGE_PROTNONE is not necessarily set for a non present
mapping, but the inversion logic explicitely checks for !PRESENT and

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

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: David Woodhouse <dwmw@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
arch/x86/include/asm/pgtable-invert.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

--- 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);

/* Get a mask to xor with the page table entry to get the correct pfn. */