[RFC PATCH 07/14] mm: do fix spurious page-faults for instruction faults

Nadav Amit
2022-07-18T19:37:30Z

From: Nadav Amit <namit@vmware.com>

The next patches might cause spurious instruction faults on x86. To
prevent them from occurring too much, call
flush_tlb_fix_spurious_fault() for page-faults on code fetching as well.
The callee is expected to do a full flush, or whatever is necessary to
avoid further TLB flushes.

Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Nick Piggin <npiggin@gmail.com>
Signed-off-by: Nadav Amit <namit@vmware.com>
---
mm/memory.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/memory.c b/mm/memory.c
index 31ec3f0071a2..152a47876c36 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -4924,7 +4924,7 @@ static vm_fault_t handle_pte_fault(struct vm_fault *vmf)
* This still avoids useless tlb flushes for .text page faults
* with threads.
*/
- if (vmf->flags & FAULT_FLAG_WRITE)
+ if (vmf->flags & (FAULT_FLAG_WRITE|FAULT_FLAG_INSTRUCTION))
flush_tlb_fix_spurious_fault(vmf->vma, vmf->address);
}
unlock:
--
2.25.1