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Tsirkin" , Laurent Vivier , Ilya Leoshkevich , Halil Pasic , =?UTF-8?q?Marc-Andr=C3=A9=20Lureau?= , Coiby Xu , Eric Farman , Alex Williamson , Christian Borntraeger , Stefan Hajnoczi , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= , Stefan Berger , Eric Blake , Eduardo Habkost , "Dr. David Alan Gilbert" , Thomas Huth , David Hildenbrand , Marcel Apfelbaum , John Snow , Yanan Wang , =?UTF-8?q?Daniel=20P=2E=20Berrang=C3=A9?= , Vladimir Sementsov-Ogievskiy , qemu-block@nongnu.org, Paolo Bonzini , Juan Quintela , Fam Zheng , qemu-s390x@nongnu.org, Peter Xu Subject: [PULL 06/26] util/userfaultfd: Add uffd_open() Date: Thu, 2 Feb 2023 17:06:20 +0100 Message-Id: <20230202160640.2300-7-quintela@redhat.com> In-Reply-To: <20230202160640.2300-1-quintela@redhat.com> References: <20230202160640.2300-1-quintela@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.5 Received-SPF: pass (zohomail.com: domain of gnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; envelope-from=qemu-devel-bounces+importer2=patchew.org@nongnu.org; helo=lists.gnu.org; Received-SPF: pass client-ip=170.10.129.124; envelope-from=quintela@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+importer2=patchew.org@nongnu.org Sender: qemu-devel-bounces+importer2=patchew.org@nongnu.org X-ZohoMail-DKIM: pass (identity @redhat.com) X-ZM-MESSAGEID: 1675354171736100001 From: Peter Xu Add a helper to create the uffd handle. Reviewed-by: Philippe Mathieu-Daud=C3=A9 Reviewed-by: Juan Quintela Signed-off-by: Peter Xu Signed-off-by: Juan Quintela --- include/qemu/userfaultfd.h | 8 ++++++++ migration/postcopy-ram.c | 11 +++++------ tests/qtest/migration-test.c | 3 ++- util/userfaultfd.c | 13 +++++++++++-- 4 files changed, 26 insertions(+), 9 deletions(-) diff --git a/include/qemu/userfaultfd.h b/include/qemu/userfaultfd.h index 6b74f92792..2101115f70 100644 --- a/include/qemu/userfaultfd.h +++ b/include/qemu/userfaultfd.h @@ -17,6 +17,14 @@ #include "exec/hwaddr.h" #include =20 +/** + * uffd_open(): Open an userfaultfd handle for current context. + * + * @flags: The flags we want to pass in when creating the handle. + * + * Returns: the uffd handle if >=3D0, or <0 if error happens. + */ +int uffd_open(int flags); int uffd_query_features(uint64_t *features); int uffd_create_fd(uint64_t features, bool non_blocking); void uffd_close_fd(int uffd_fd); diff --git a/migration/postcopy-ram.c b/migration/postcopy-ram.c index b9a37ef255..0c55df0e52 100644 --- a/migration/postcopy-ram.c +++ b/migration/postcopy-ram.c @@ -37,6 +37,7 @@ #include "qemu-file.h" #include "yank_functions.h" #include "tls.h" +#include "qemu/userfaultfd.h" =20 /* Arbitrary limit on size of each discard command, * keeps them around ~200 bytes @@ -226,11 +227,9 @@ static bool receive_ufd_features(uint64_t *features) int ufd; bool ret =3D true; =20 - /* if we are here __NR_userfaultfd should exists */ - ufd =3D syscall(__NR_userfaultfd, O_CLOEXEC); + ufd =3D uffd_open(O_CLOEXEC); if (ufd =3D=3D -1) { - error_report("%s: syscall __NR_userfaultfd failed: %s", __func__, - strerror(errno)); + error_report("%s: uffd_open() failed: %s", __func__, strerror(errn= o)); return false; } =20 @@ -375,7 +374,7 @@ bool postcopy_ram_supported_by_host(MigrationIncomingSt= ate *mis) goto out; } =20 - ufd =3D syscall(__NR_userfaultfd, O_CLOEXEC); + ufd =3D uffd_open(O_CLOEXEC); if (ufd =3D=3D -1) { error_report("%s: userfaultfd not available: %s", __func__, strerror(errno)); @@ -1160,7 +1159,7 @@ static int postcopy_temp_pages_setup(MigrationIncomin= gState *mis) int postcopy_ram_incoming_setup(MigrationIncomingState *mis) { /* Open the fd for the kernel to give us userfaults */ - mis->userfault_fd =3D syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK= ); + mis->userfault_fd =3D uffd_open(O_CLOEXEC | O_NONBLOCK); if (mis->userfault_fd =3D=3D -1) { error_report("%s: Failed to open userfault fd: %s", __func__, strerror(errno)); diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c index 1dd32c9506..7a5d1922dd 100644 --- a/tests/qtest/migration-test.c +++ b/tests/qtest/migration-test.c @@ -62,13 +62,14 @@ static bool uffd_feature_thread_id; #include #include #include +#include "qemu/userfaultfd.h" =20 static bool ufd_version_check(void) { struct uffdio_api api_struct; uint64_t ioctl_mask; =20 - int ufd =3D syscall(__NR_userfaultfd, O_CLOEXEC); + int ufd =3D uffd_open(O_CLOEXEC); =20 if (ufd =3D=3D -1) { g_test_message("Skipping test: userfaultfd not available"); diff --git a/util/userfaultfd.c b/util/userfaultfd.c index f1cd6af2b1..4953b3137d 100644 --- a/util/userfaultfd.c +++ b/util/userfaultfd.c @@ -19,6 +19,15 @@ #include #include =20 +int uffd_open(int flags) +{ +#if defined(__NR_userfaultfd) + return syscall(__NR_userfaultfd, flags); +#else + return -EINVAL; +#endif +} + /** * uffd_query_features: query UFFD features * @@ -32,7 +41,7 @@ int uffd_query_features(uint64_t *features) struct uffdio_api api_struct =3D { 0 }; int ret =3D -1; =20 - uffd_fd =3D syscall(__NR_userfaultfd, O_CLOEXEC); + uffd_fd =3D uffd_open(O_CLOEXEC); if (uffd_fd < 0) { trace_uffd_query_features_nosys(errno); return -1; @@ -69,7 +78,7 @@ int uffd_create_fd(uint64_t features, bool non_blocking) uint64_t ioctl_mask =3D BIT(_UFFDIO_REGISTER) | BIT(_UFFDIO_UNREGISTER= ); =20 flags =3D O_CLOEXEC | (non_blocking ? O_NONBLOCK : 0); - uffd_fd =3D syscall(__NR_userfaultfd, flags); + uffd_fd =3D uffd_open(flags); if (uffd_fd < 0) { trace_uffd_create_fd_nosys(errno); return -1; --=20 2.39.1