Rather than assuming which PTE the SMEP test is running on, look it up
to ensure we have the correct entry. If this test were to run on a
different page table (ie: run in an L2 test) the wrong PTE would be set.
Switch to looking up the PTE to avoid this from happening.
Signed-off-by: Aaron Lewis <aaronlewis@xxxxxxxxxx>
---
x86/access.c | 9 ++++++---
x86/cstart64.S | 1 -
2 files changed, 6 insertions(+), 4 deletions(-)
diff --git a/x86/access.c b/x86/access.c
index 4725bbd..a4d72d9 100644
--- a/x86/access.c
+++ b/x86/access.c
@@ -204,7 +204,7 @@ static void set_cr0_wp(int wp)
static unsigned set_cr4_smep(int smep)
{
unsigned long cr4 = shadow_cr4;
- extern u64 ptl2[];
+ pteval_t *pte;
unsigned r;
cr4 &= ~CR4_SMEP_MASK;
@@ -213,11 +213,14 @@ static unsigned set_cr4_smep(int smep)
if (cr4 == shadow_cr4)
return 0;
+ pte = get_pte(phys_to_virt(read_cr3()), set_cr4_smep);
+ assert(pte);
+
if (smep)
- ptl2[2] &= ~PT_USER_MASK;
+ *pte &= ~PT_USER_MASK;
r = write_cr4_checking(cr4);
if (r || !smep) {
- ptl2[2] |= PT_USER_MASK;
+ *pte |= PT_USER_MASK;
/* Flush to avoid spurious #PF */
invlpg((void *)(2 << 21));
diff --git a/x86/cstart64.S b/x86/cstart64.S
index 5c6ad38..4ba9943 100644
--- a/x86/cstart64.S
+++ b/x86/cstart64.S
@@ -26,7 +26,6 @@ ring0stacktop:
.data
.align 4096
-.globl ptl2
ptl2:
i = 0
.rept 512 * 4
--
2.33.1.1089.g2158813163f-goog
