From: Axel Rasmussen <axelrasmussen@google.com>
To: Alexander Viro <viro@zeniv.linux.org.uk>,
Andrea Arcangeli <aarcange@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
Jerome Glisse <jglisse@redhat.com>, Joe Perches <joe@perches.com>,
Lokesh Gidra <lokeshgidra@google.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Peter Xu <peterx@redhat.com>, Shaohua Li <shli@fb.com>,
Shuah Khan <shuah@kernel.org>,
Stephen Rothwell <sfr@canb.auug.org.au>,
Wang Qing <wangqing@vivo.com>
Cc: linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
linux-mm@kvack.org, Axel Rasmussen <axelrasmussen@google.com>,
Brian Geffon <bgeffon@google.com>,
"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
Mina Almasry <almasrymina@google.com>,
Oliver Upton <oupton@google.com>
Subject: [PATCH v5 05/10] userfaultfd/shmem: advertise shmem minor fault support
Date: Tue, 27 Apr 2021 15:52:39 -0700 [thread overview]
Message-ID: <20210427225244.4326-6-axelrasmussen@google.com> (raw)
In-Reply-To: <20210427225244.4326-1-axelrasmussen@google.com>
Now that the feature is fully implemented (the faulting path hooks exist
so userspace is notified, and the ioctl to resolve such faults is
available), advertise this as a supported feature.
Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
---
Documentation/admin-guide/mm/userfaultfd.rst | 3 ++-
fs/userfaultfd.c | 3 ++-
include/uapi/linux/userfaultfd.h | 7 ++++++-
3 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/Documentation/admin-guide/mm/userfaultfd.rst b/Documentation/admin-guide/mm/userfaultfd.rst
index 3aa38e8b8361..6528036093e1 100644
--- a/Documentation/admin-guide/mm/userfaultfd.rst
+++ b/Documentation/admin-guide/mm/userfaultfd.rst
@@ -77,7 +77,8 @@ events, except page fault notifications, may be generated:
- ``UFFD_FEATURE_MINOR_HUGETLBFS`` indicates that the kernel supports
``UFFDIO_REGISTER_MODE_MINOR`` registration for hugetlbfs virtual memory
- areas.
+ areas. ``UFFD_FEATURE_MINOR_SHMEM`` is the analogous feature indicating
+ support for shmem virtual memory areas.
The userland application should set the feature flags it intends to use
when invoking the ``UFFDIO_API`` ioctl, to request that those features be
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 468556fb04a9..9f3b8684cf3c 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1940,7 +1940,8 @@ static int userfaultfd_api(struct userfaultfd_ctx *ctx,
/* report all available features and ioctls to userland */
uffdio_api.features = UFFD_API_FEATURES;
#ifndef CONFIG_HAVE_ARCH_USERFAULTFD_MINOR
- uffdio_api.features &= ~UFFD_FEATURE_MINOR_HUGETLBFS;
+ uffdio_api.features &=
+ ~(UFFD_FEATURE_MINOR_HUGETLBFS | UFFD_FEATURE_MINOR_SHMEM);
#endif
uffdio_api.ioctls = UFFD_API_IOCTLS;
ret = -EFAULT;
diff --git a/include/uapi/linux/userfaultfd.h b/include/uapi/linux/userfaultfd.h
index bafbeb1a2624..159a74e9564f 100644
--- a/include/uapi/linux/userfaultfd.h
+++ b/include/uapi/linux/userfaultfd.h
@@ -31,7 +31,8 @@
UFFD_FEATURE_MISSING_SHMEM | \
UFFD_FEATURE_SIGBUS | \
UFFD_FEATURE_THREAD_ID | \
- UFFD_FEATURE_MINOR_HUGETLBFS)
+ UFFD_FEATURE_MINOR_HUGETLBFS | \
+ UFFD_FEATURE_MINOR_SHMEM)
#define UFFD_API_IOCTLS \
((__u64)1 << _UFFDIO_REGISTER | \
(__u64)1 << _UFFDIO_UNREGISTER | \
@@ -185,6 +186,9 @@ struct uffdio_api {
* UFFD_FEATURE_MINOR_HUGETLBFS indicates that minor faults
* can be intercepted (via REGISTER_MODE_MINOR) for
* hugetlbfs-backed pages.
+ *
+ * UFFD_FEATURE_MINOR_SHMEM indicates the same support as
+ * UFFD_FEATURE_MINOR_HUGETLBFS, but for shmem-backed pages instead.
*/
#define UFFD_FEATURE_PAGEFAULT_FLAG_WP (1<<0)
#define UFFD_FEATURE_EVENT_FORK (1<<1)
@@ -196,6 +200,7 @@ struct uffdio_api {
#define UFFD_FEATURE_SIGBUS (1<<7)
#define UFFD_FEATURE_THREAD_ID (1<<8)
#define UFFD_FEATURE_MINOR_HUGETLBFS (1<<9)
+#define UFFD_FEATURE_MINOR_SHMEM (1<<10)
__u64 features;
__u64 ioctls;
--
2.31.1.498.g6c1eba8ee3d-goog
next prev parent reply other threads:[~2021-04-27 22:54 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-27 22:52 [PATCH v5 00/10] userfaultfd: add minor fault handling for shmem Axel Rasmussen
2021-04-27 22:52 ` [PATCH v5 01/10] userfaultfd/hugetlbfs: avoid including userfaultfd_k.h in hugetlb.h Axel Rasmussen
2021-04-27 22:52 ` [PATCH v5 02/10] userfaultfd/shmem: combine shmem_{mcopy_atomic,mfill_zeropage}_pte Axel Rasmussen
2021-04-27 22:52 ` [PATCH v5 03/10] userfaultfd/shmem: support minor fault registration for shmem Axel Rasmussen
2021-04-28 0:02 ` Hugh Dickins
2021-04-27 22:52 ` [PATCH v5 04/10] userfaultfd/shmem: support UFFDIO_CONTINUE " Axel Rasmussen
2021-04-28 0:03 ` Hugh Dickins
2021-04-28 15:10 ` Peter Xu
2021-04-27 22:52 ` Axel Rasmussen [this message]
2021-04-28 0:04 ` [PATCH v5 05/10] userfaultfd/shmem: advertise shmem minor fault support Hugh Dickins
2021-04-28 15:11 ` Peter Xu
2021-04-27 22:52 ` [PATCH v5 06/10] userfaultfd/shmem: modify shmem_mcopy_atomic_pte to use install_pte() Axel Rasmussen
2021-04-28 0:58 ` Hugh Dickins
2021-04-28 15:56 ` Peter Xu
2021-04-28 15:59 ` Axel Rasmussen
2021-04-28 16:23 ` Peter Xu
2021-04-27 22:52 ` [PATCH v5 07/10] userfaultfd/selftests: use memfd_create for shmem test type Axel Rasmussen
2021-04-27 22:52 ` [PATCH v5 08/10] userfaultfd/selftests: create alias mappings in the shmem test Axel Rasmussen
2021-04-27 22:52 ` [PATCH v5 09/10] userfaultfd/selftests: reinitialize test context in each test Axel Rasmussen
2021-04-28 17:23 ` Peter Xu
2021-05-18 20:57 ` Peter Xu
2021-05-18 22:28 ` Axel Rasmussen
2021-04-27 22:52 ` [PATCH v5 10/10] userfaultfd/selftests: exercise minor fault handling shmem support Axel Rasmussen
2021-04-28 17:26 ` Peter Xu
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