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 02/14] userfaultfd: try to map write-unprotected pages
Date: Mon, 18 Jul 2022 05:02:00 -0700 [thread overview]
Message-ID: <20220718120212.3180-3-namit@vmware.com> (raw)
In-Reply-To: <20220718120212.3180-1-namit@vmware.com>
From: Nadav Amit <namit@vmware.com>
When using userfaultfd write-(un)protect ioctl, try to change the PTE to
be writable. This would save a page-fault afterwards.
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/userfaultfd.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/userfaultfd.c b/mm/userfaultfd.c
index e0492f5f06a0..6013b217e9f3 100644
--- a/mm/userfaultfd.c
+++ b/mm/userfaultfd.c
@@ -799,6 +799,8 @@ int mwriteprotect_range(struct mm_struct *dst_mm, unsigned long start,
cp_flags = enable_wp ? MM_CP_UFFD_WP : MM_CP_UFFD_WP_RESOLVE;
if (uffd_flags & (UFFD_FLAGS_ACCESS_LIKELY|UFFD_FLAGS_WRITE_LIKELY))
cp_flags |= MM_CP_WILL_NEED;
+ if (!enable_wp && (uffd_flags & UFFD_FLAGS_WRITE_LIKELY))
+ cp_flags |= MM_CP_TRY_CHANGE_WRITABLE;
tlb_gather_mmu(&tlb, dst_mm);
change_protection(&tlb, dst_vma, start, start + len, newprot, cp_flags);
--
2.25.1
next prev parent reply other threads:[~2022-07-18 19:37 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-18 12:01 [RFC PATCH 00/14] mm: relaxed TLB flushes and other optimi Nadav Amit
2022-07-18 12:01 ` [RFC PATCH 01/14] userfaultfd: set dirty and young on writeprotect Nadav Amit
2022-07-19 20:47 ` Peter Xu
2022-07-20 9:39 ` David Hildenbrand
2022-07-20 13:10 ` Peter Xu
2022-07-20 15:10 ` David Hildenbrand
2022-07-20 19:15 ` Peter Xu
2022-07-20 19:33 ` David Hildenbrand
2022-07-20 19:48 ` Peter Xu
2022-07-20 19:55 ` David Hildenbrand
2022-07-20 20:22 ` Nadav Amit
2022-07-20 20:38 ` David Hildenbrand
2022-07-20 20:56 ` Nadav Amit
2022-07-21 7:52 ` David Hildenbrand
2022-07-21 14:10 ` David Hildenbrand
2022-07-20 9:42 ` David Hildenbrand
2022-07-20 17:36 ` Nadav Amit
2022-07-20 18:00 ` David Hildenbrand
2022-07-20 18:09 ` Nadav Amit
2022-07-20 18:11 ` David Hildenbrand
2022-07-18 12:02 ` Nadav Amit [this message]
2022-07-19 20:49 ` [RFC PATCH 02/14] userfaultfd: try to map write-unprotected pages Peter Xu
2022-07-18 12:02 ` [RFC PATCH 03/14] mm/mprotect: allow exclusive anon pages to be writable Nadav Amit
2022-07-20 15:19 ` David Hildenbrand
2022-07-20 17:25 ` Nadav Amit
2022-07-21 7:45 ` David Hildenbrand
2022-07-18 12:02 ` [RFC PATCH 04/14] mm/mprotect: preserve write with MM_CP_TRY_CHANGE_WRITABLE Nadav Amit
2022-07-18 12:02 ` [RFC PATCH 05/14] x86/mm: check exec permissions on fault Nadav Amit
2022-07-18 12:02 ` [RFC PATCH 06/14] mm/rmap: avoid flushing on page_vma_mkclean_one() when possible Nadav Amit
2022-07-18 12:02 ` [RFC PATCH 07/14] mm: do fix spurious page-faults for instruction faults Nadav Amit
2022-07-18 12:02 ` [RFC PATCH 08/14] x86/mm: introduce flush_tlb_fix_spurious_fault Nadav Amit
2022-07-18 12:02 ` [RFC PATCH 09/14] mm: introduce relaxed TLB flushes Nadav Amit
2022-07-18 12:02 ` [RFC PATCH 10/14] x86/mm: " Nadav Amit
2022-07-18 12:02 ` [RFC PATCH 11/14] x86/mm: use relaxed TLB flushes when protection is removed Nadav Amit
2022-07-18 12:02 ` [RFC PATCH 12/14] x86/tlb: no flush on PTE change from RW->RO when PTE is clean Nadav Amit
2022-07-18 12:02 ` [RFC PATCH 13/14] mm/mprotect: do not check flush type if a strict is needed Nadav Amit
2022-07-18 12:02 ` [RFC PATCH 14/14] mm: conditional check of pfn in pte_flush_type Nadav Amit
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20220718120212.3180-3-namit@vmware.com \
--to=nadav.amit@gmail.com \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=andrew.cooper3@citrix.com \
--cc=axelrasmussen@google.com \
--cc=dave.hansen@linux.intel.com \
--cc=david@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=luto@kernel.org \
--cc=namit@vmware.com \
--cc=npiggin@gmail.com \
--cc=peterx@redhat.com \
--cc=peterz@infradead.org \
--cc=rppt@linux.ibm.com \
--cc=tglx@linutronix.de \
--cc=will@kernel.org \
--cc=yuzhao@google.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.