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From:   Nadav Amit <nadav.amit@gmail.com>
To:     linux-mm@kvack.org
Cc:     linux-kernel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Axel Rasmussen <axelrasmussen@google.com>,
        Nadav Amit <namit@vmware.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Andrew Cooper <andrew.cooper3@citrix.com>,
        Andy Lutomirski <luto@kernel.org>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        David Hildenbrand <david@redhat.com>,
        Peter Xu <peterx@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Will Deacon <will@kernel.org>, Yu Zhao <yuzhao@google.com>,
        Nick Piggin <npiggin@gmail.com>
Subject: [RFC PATCH 07/14] mm: do fix spurious page-faults for instruction faults
Date:   Mon, 18 Jul 2022 05:02:05 -0700
Message-Id: <20220718120212.3180-8-namit@vmware.com>
In-Reply-To: <20220718120212.3180-1-namit@vmware.com>
References: <20220718120212.3180-1-namit@vmware.com>
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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