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Berrange" , Markus Armbruster , Steve Sistare Subject: [PATCH V2 10/11] migration: cpr-exec save and load Date: Sun, 30 Jun 2024 12:40:33 -0700 Message-Id: <1719776434-435013-11-git-send-email-steven.sistare@oracle.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1719776434-435013-1-git-send-email-steven.sistare@oracle.com> References: <1719776434-435013-1-git-send-email-steven.sistare@oracle.com> X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1039,Hydra:6.0.680,FMLib:17.12.28.16 definitions=2024-06-30_16,2024-06-28_01,2024-05-17_01 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 malwarescore=0 adultscore=0 bulkscore=0 mlxlogscore=999 phishscore=0 spamscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2406180000 definitions=main-2406300157 X-Proofpoint-GUID: dfX4xSzsgK0SbDrY6mNJmAPiS-CwiTHy X-Proofpoint-ORIG-GUID: dfX4xSzsgK0SbDrY6mNJmAPiS-CwiTHy Received-SPF: pass client-ip=205.220.165.32; envelope-from=steven.sistare@oracle.com; helo=mx0a-00069f02.pphosted.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_MED=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_MSPIKE_H3=-0.01, RCVD_IN_MSPIKE_WL=-0.01, 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 To preserve CPR state across exec, create a QEMUFile based on a memfd, and keep the memfd open across exec. Save the value of the memfd in an environment variable so post-exec QEMU can find it. These new functions are called in a subsequent patch. Signed-off-by: Steve Sistare --- include/migration/cpr.h | 5 +++ migration/cpr-exec.c | 95 +++++++++++++++++++++++++++++++++++++++++++++++++ migration/meson.build | 1 + 3 files changed, 101 insertions(+) create mode 100644 migration/cpr-exec.c diff --git a/include/migration/cpr.h b/include/migration/cpr.h index 42b4019..76d6ccb 100644 --- a/include/migration/cpr.h +++ b/include/migration/cpr.h @@ -25,4 +25,9 @@ void cpr_resave_fd(const char *name, int id, int fd); int cpr_state_save(Error **errp); int cpr_state_load(Error **errp); +QEMUFile *cpr_exec_output(Error **errp); +QEMUFile *cpr_exec_input(Error **errp); +void cpr_exec_persist_state(QEMUFile *f); +bool cpr_exec_has_state(void); +void cpr_exec_unpersist_state(void); #endif diff --git a/migration/cpr-exec.c b/migration/cpr-exec.c new file mode 100644 index 0000000..5c40457 --- /dev/null +++ b/migration/cpr-exec.c @@ -0,0 +1,95 @@ +/* + * Copyright (c) 2021-2024 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 "io/channel-socket.h" +#include "migration/cpr.h" +#include "migration/qemu-file.h" +#include "migration/misc.h" +#include "migration/vmstate.h" +#include "sysemu/runstate.h" + +#define CPR_EXEC_STATE_NAME "QEMU_CPR_EXEC_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); +} + +void cpr_exec_persist_state(QEMUFile *f) +{ + QIOChannelFile *fioc = QIO_CHANNEL_FILE(qemu_file_get_ioc(f)); + int mfd = dup(fioc->fd); + char val[16]; + + /* Remember mfd in environment for post-exec load */ + qemu_clear_cloexec(mfd); + snprintf(val, sizeof(val), "%d", mfd); + g_setenv(CPR_EXEC_STATE_NAME, val, 1); +} + +static int cpr_exec_find_state(void) +{ + const char *val = g_getenv(CPR_EXEC_STATE_NAME); + int mfd; + + assert(val); + g_unsetenv(CPR_EXEC_STATE_NAME); + assert(!qemu_strtoi(val, NULL, 10, &mfd)); + return mfd; +} + +bool cpr_exec_has_state(void) +{ + return g_getenv(CPR_EXEC_STATE_NAME) != NULL; +} + +void cpr_exec_unpersist_state(void) +{ + int mfd; + const char *val = g_getenv(CPR_EXEC_STATE_NAME); + + g_unsetenv(CPR_EXEC_STATE_NAME); + assert(val); + assert(!qemu_strtoi(val, NULL, 10, &mfd)); + close(mfd); +} + +QEMUFile *cpr_exec_output(Error **errp) +{ + int mfd = memfd_create(CPR_EXEC_STATE_NAME, 0); + + if (mfd < 0) { + error_setg_errno(errp, errno, "memfd_create failed"); + return NULL; + } + + return qemu_file_new_fd_output(mfd, CPR_EXEC_STATE_NAME); +} + +QEMUFile *cpr_exec_input(Error **errp) +{ + int mfd = cpr_exec_find_state(); + + lseek(mfd, 0, SEEK_SET); + return qemu_file_new_fd_input(mfd, CPR_EXEC_STATE_NAME); +} diff --git a/migration/meson.build b/migration/meson.build index 87feb4c..dd1d315 100644 --- a/migration/meson.build +++ b/migration/meson.build @@ -14,6 +14,7 @@ system_ss.add(files( 'channel.c', 'channel-block.c', 'cpr.c', + 'cpr-exec.c', 'dirtyrate.c', 'exec.c', 'fd.c',