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Berrange" , Markus Armbruster , Steve Sistare Subject: [PATCH V1 06/26] migration: precreate vmstate for exec Date: Mon, 29 Apr 2024 08:55:15 -0700 Message-Id: <1714406135-451286-7-git-send-email-steven.sistare@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1714406135-451286-1-git-send-email-steven.sistare@oracle.com> References: <1714406135-451286-1-git-send-email-steven.sistare@oracle.com> X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1011,Hydra:6.0.650,FMLib:17.11.176.26 definitions=2024-04-29_14,2024-04-29_01,2023-05-22_02 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 mlxlogscore=999 malwarescore=0 adultscore=0 mlxscore=0 suspectscore=0 phishscore=0 spamscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2404010000 definitions=main-2404290101 X-Proofpoint-GUID: ZbprD0pcIER2DImXWwmIew0YnfdbXrb_ X-Proofpoint-ORIG-GUID: ZbprD0pcIER2DImXWwmIew0YnfdbXrb_ Received-SPF: pass client-ip=205.220.177.32; envelope-from=steven.sistare@oracle.com; helo=mx0b-00069f02.pphosted.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_MED=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham 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+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Provide migration_precreate_save for saving precreate vmstate across exec. Create a memfd, save its value in the environment, and serialize state to it. Reverse the process in migration_precreate_load. Signed-off-by: Steve Sistare Reviewed-by: Fabiano Rosas --- include/migration/misc.h | 5 ++ migration/meson.build | 1 + migration/precreate.c | 139 +++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 145 insertions(+) create mode 100644 migration/precreate.c diff --git a/include/migration/misc.h b/include/migration/misc.h index c9e200f..cf30351 100644 --- a/include/migration/misc.h +++ b/include/migration/misc.h @@ -56,6 +56,11 @@ AnnounceParameters *migrate_announce_params(void); void dump_vmstate_json_to_file(FILE *out_fp); +/* migration/precreate.c */ +int migration_precreate_save(Error **errp); +void migration_precreate_unsave(void); +int migration_precreate_load(Error **errp); + /* migration/migration.c */ void migration_object_init(void); void migration_shutdown(void); diff --git a/migration/meson.build b/migration/meson.build index f76b1ba..50e7cb2 100644 --- a/migration/meson.build +++ b/migration/meson.build @@ -26,6 +26,7 @@ system_ss.add(files( 'ram-compress.c', 'options.c', 'postcopy-ram.c', + 'precreate.c', 'savevm.c', 'socket.c', 'tls.c', diff --git a/migration/precreate.c b/migration/precreate.c new file mode 100644 index 0000000..0bf5e1f --- /dev/null +++ b/migration/precreate.c @@ -0,0 +1,139 @@ +/* + * Copyright (c) 2022, 2024 Oracle and/or its affiliates. + * + * This work is licensed under the terms of the GNU GPL, version 2 or later. + * See the COPYING file in the top-level directory. + */ + +#include "qemu/osdep.h" +#include "qemu/cutils.h" +#include "qemu/memfd.h" +#include "qapi/error.h" +#include "io/channel-file.h" +#include "migration/misc.h" +#include "migration/qemu-file.h" +#include "migration/savevm.h" + +#define PRECREATE_STATE_NAME "QEMU_PRECREATE_STATE" + +static QEMUFile *qemu_file_new_fd_input(int fd, const char *name) +{ + g_autoptr(QIOChannelFile) fioc = qio_channel_file_new_fd(fd); + QIOChannel *ioc = QIO_CHANNEL(fioc); + qio_channel_set_name(ioc, name); + return qemu_file_new_input(ioc); +} + +static QEMUFile *qemu_file_new_fd_output(int fd, const char *name) +{ + g_autoptr(QIOChannelFile) fioc = qio_channel_file_new_fd(fd); + QIOChannel *ioc = QIO_CHANNEL(fioc); + qio_channel_set_name(ioc, name); + return qemu_file_new_output(ioc); +} + +static int memfd_create_named(const char *name, Error **errp) +{ + int mfd; + char val[16]; + + mfd = memfd_create(name, 0); + if (mfd < 0) { + error_setg_errno(errp, errno, "memfd_create failed"); + return -1; + } + + /* Remember mfd in environment for post-exec load */ + qemu_clear_cloexec(mfd); + snprintf(val, sizeof(val), "%d", mfd); + g_setenv(name, val, 1); + + return mfd; +} + +static int memfd_find_named(const char *name, int *mfd_p, Error **errp) +{ + const char *val = g_getenv(name); + + if (!val) { + *mfd_p = -1; + return 0; /* No memfd was created, not an error */ + } + g_unsetenv(name); + if (qemu_strtoi(val, NULL, 10, mfd_p)) { + error_setg(errp, "Bad %s env value %s", PRECREATE_STATE_NAME, val); + return -1; + } + lseek(*mfd_p, 0, SEEK_SET); + return 0; +} + +static void memfd_delete_named(const char *name) +{ + int mfd; + const char *val = g_getenv(name); + + if (val) { + g_unsetenv(name); + if (!qemu_strtoi(val, NULL, 10, &mfd)) { + close(mfd); + } + } +} + +static QEMUFile *qemu_file_new_memfd_output(const char *name, Error **errp) +{ + int mfd = memfd_create_named(name, errp); + + if (mfd < 0) { + return NULL; + } + + return qemu_file_new_fd_output(mfd, name); +} + +static QEMUFile *qemu_file_new_memfd_input(const char *name, Error **errp) +{ + int ret, mfd; + + ret = memfd_find_named(name, &mfd, errp); + if (ret || mfd < 0) { + return NULL; + } + + return qemu_file_new_fd_input(mfd, name); +} + +int migration_precreate_save(Error **errp) +{ + QEMUFile *f = qemu_file_new_memfd_output(PRECREATE_STATE_NAME, errp); + + if (!f) { + return -1; + } else if (qemu_savevm_precreate_save(f, errp)) { + memfd_delete_named(PRECREATE_STATE_NAME); + return -1; + } else { + /* Do not close f, as mfd must remain open. */ + return 0; + } +} + +void migration_precreate_unsave(void) +{ + memfd_delete_named(PRECREATE_STATE_NAME); +} + +int migration_precreate_load(Error **errp) +{ + int ret; + QEMUFile *f = qemu_file_new_memfd_input(PRECREATE_STATE_NAME, errp); + + if (!f) { + return -1; + } + ret = qemu_savevm_precreate_load(f, errp); + qemu_fclose(f); + g_unsetenv(PRECREATE_STATE_NAME); + return ret; +}