Merge tag 'migration-20240621-pull-request' of https://gitlab.com/farosas/qemu into staging

Migration pull request

- Fabiano's fix for fdset + file migration truncating the migration
  file

- Fabiano's fdset + direct-io support for mapped-ram

- Peter's various cleanups (multifd sync, thread names, migration
  states, tests)

- Peter's new migration state postcopy-recover-setup

- Philippe's unused vmstate macro cleanup

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# gpg:                using RSA key AA1B48B0A22326A5A4C364CFC798DC741BEC319D
# gpg:                issuer "farosas@suse.de"
# gpg: Good signature from "Fabiano Rosas <farosas@suse.de>" [unknown]
# gpg:                 aka "Fabiano Almeida Rosas <fabiano.rosas@suse.com>" [unknown]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: AA1B 48B0 A223 26A5 A4C3  64CF C798 DC74 1BEC 319D

* tag 'migration-20240621-pull-request' of https://gitlab.com/farosas/qemu: (28 commits)
  migration: Remove unused VMSTATE_ARRAY_TEST() macro
  tests/migration-tests: Cover postcopy failure on reconnect
  tests/migration-tests: Verify postcopy-recover-setup status
  tests/migration-tests: migration_event_wait()
  tests/migration-tests: Always enable migration events
  tests/migration-tests: Drop most WIN32 ifdefs for postcopy failure tests
  migration/docs: Update postcopy recover session for SETUP phase
  migration/postcopy: Add postcopy-recover-setup phase
  migration: Cleanup incoming migration setup state change
  migration: Use MigrationStatus instead of int
  migration: Rename thread debug names
  migration/multifd: Avoid the final FLUSH in complete()
  tests/qtest/migration: Add a test for mapped-ram with passing of fds
  migration: Add documentation for fdset with multifd + file
  monitor: fdset: Match against O_DIRECT
  tests/qtest/migration: Add tests for file migration with direct-io
  migration/multifd: Add direct-io support
  migration: Add direct-io parameter
  io: Stop using qemu_open_old in channel-file
  monitor: Report errors from monitor_fdset_dup_fd_add
  ...

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

1 files changed, 38 insertions, 7 deletions

diff --git a/migration/file.c b/migration/file.c
index ab18ba505a..db870f2cf0 100644
--- a/migration/file.c
+++ b/migration/file.c
@@ -50,12 +50,31 @@ void file_cleanup_outgoing_migration(void)
     outgoing_args.fname = NULL;
 }
 
+static void file_enable_direct_io(int *flags)
+{
+#ifdef O_DIRECT
+    *flags |= O_DIRECT;
+#else
+    /* it should have been rejected when setting the parameter */
+    g_assert_not_reached();
+#endif
+}
+
 bool file_send_channel_create(gpointer opaque, Error **errp)
 {
     QIOChannelFile *ioc;
     int flags = O_WRONLY;
     bool ret = true;
 
+    if (migrate_direct_io()) {
+        /*
+         * Enable O_DIRECT for the secondary channels. These are used
+         * for sending ram pages and writes should be guaranteed to be
+         * aligned to at least page size.
+         */
+        file_enable_direct_io(&flags);
+    }
+
     ioc = qio_channel_file_new_path(outgoing_args.fname, flags, 0, errp);
     if (!ioc) {
         ret = false;
@@ -84,16 +103,24 @@ void file_start_outgoing_migration(MigrationState *s,
 
     trace_migration_file_outgoing(filename);
 
-    fioc = qio_channel_file_new_path(filename, O_CREAT | O_WRONLY | O_TRUNC,
-                                     0600, errp);
+    fioc = qio_channel_file_new_path(filename, O_CREAT | O_WRONLY, 0600, errp);
     if (!fioc) {
         return;
     }
 
+    if (ftruncate(fioc->fd, offset)) {
+        error_setg_errno(errp, errno,
+                         "failed to truncate migration file to offset %" PRIx64,
+                         offset);
+        object_unref(OBJECT(fioc));
+        return;
+    }
+
     outgoing_args.fname = g_strdup(filename);
 
     ioc = QIO_CHANNEL(fioc);
     if (offset && qio_channel_io_seek(ioc, offset, SEEK_SET, errp) < 0) {
+        object_unref(OBJECT(fioc));
         return;
     }
     qio_channel_set_name(ioc, "migration-file-outgoing");
@@ -109,21 +136,25 @@ static gboolean file_accept_incoming_migration(QIOChannel *ioc,
     return G_SOURCE_REMOVE;
 }
 
-void file_create_incoming_channels(QIOChannel *ioc, Error **errp)
+static void file_create_incoming_channels(QIOChannel *ioc, char *filename,
+                                          Error **errp)
 {
-    int i, fd, channels = 1;
+    int i, channels = 1;
     g_autofree QIOChannel **iocs = NULL;
+    int flags = O_RDONLY;
 
     if (migrate_multifd()) {
         channels += migrate_multifd_channels();
+        if (migrate_direct_io()) {
+            file_enable_direct_io(&flags);
+        }
     }
 
     iocs = g_new0(QIOChannel *, channels);
-    fd = QIO_CHANNEL_FILE(ioc)->fd;
     iocs[0] = ioc;
 
     for (i = 1; i < channels; i++) {
-        QIOChannelFile *fioc = qio_channel_file_new_dupfd(fd, errp);
+        QIOChannelFile *fioc = qio_channel_file_new_path(filename, flags, 0, errp);
 
         if (!fioc) {
             while (i) {
@@ -163,7 +194,7 @@ void file_start_incoming_migration(FileMigrationArgs *file_args, Error **errp)
         return;
     }
 
-    file_create_incoming_channels(QIO_CHANNEL(fioc), errp);
+    file_create_incoming_channels(QIO_CHANNEL(fioc), filename, errp);
 }
 
 int file_write_ramblock_iov(QIOChannel *ioc, const struct iovec *iov,