Re: [PATCH V1 06/26] migration: precreate vmstate for exec
Steven Sistare writes:
> On 5/6/2024 7:34 PM, Fabiano Rosas wrote:
>> Steve Sistare writes:
>>
>>> 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
>>> ---
>>> 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 000..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, )) {
>>> +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, , 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) {
>>> +
Re: [PATCH V1 06/26] migration: precreate vmstate for exec
On 5/6/2024 7:34 PM, Fabiano Rosas wrote:
Steve Sistare writes:
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
---
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 000..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, )) {
+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, , 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);
Can we avoid the QEMUFile? I don't see it being exported from this file.
It is not exported, but within this file, it is the basis for all read and
write operations, via the existing functions
Re: [PATCH V1 06/26] migration: precreate vmstate for exec
Steve Sistare writes:
> 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
> ---
> 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 000..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, )) {
> +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, , 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)
> +{
> +
[PATCH V1 06/26] migration: precreate vmstate for exec
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
---
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 000..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, )) {
+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, , 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;
+}
--
1.8.3.1
