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

Migartion pull request for 20240304

- Bryan's fix on multifd compression level API
- Fabiano's mapped-ram series (base + multifd only)
- Steve's amend on cpr document in qapi/

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* tag 'migration-next-pull-request' of https://gitlab.com/peterx/qemu: (27 commits)
  migration/multifd: Document two places for mapped-ram
  tests/qtest/migration: Add a multifd + mapped-ram migration test
  migration/multifd: Add mapped-ram support to fd: URI
  migration/multifd: Support incoming mapped-ram stream format
  migration/multifd: Support outgoing mapped-ram stream format
  migration/multifd: Prepare multifd sync for mapped-ram migration
  migration/multifd: Add incoming QIOChannelFile support
  migration/multifd: Add outgoing QIOChannelFile support
  migration/multifd: Add a wrapper for channels_created
  migration/multifd: Allow receiving pages without packets
  migration/multifd: Allow multifd without packets
  migration/multifd: Decouple recv method from pages
  migration/multifd: Rename MultiFDSend|RecvParams::data to compress_data
  tests/qtest/migration: Add tests for mapped-ram file-based migration
  migration/ram: Add incoming 'mapped-ram' migration
  migration/ram: Add outgoing 'mapped-ram' migration
  migration: Add mapped-ram URI compatibility check
  migration/ram: Introduce 'mapped-ram' migration capability
  migration/qemu-file: add utility methods for working with seekable channels
  io: fsync before closing a file channel
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

# Conflicts:
#	migration/ram.c

1 files changed, 106 insertions, 0 deletions

diff --git a/migration/qemu-file.c b/migration/qemu-file.c
index 94231ff295..b10c882629 100644
--- a/migration/qemu-file.c
+++ b/migration/qemu-file.c
@@ -33,6 +33,7 @@
 #include "options.h"
 #include "qapi/error.h"
 #include "rdma.h"
+#include "io/channel-file.h"
 
 #define IO_BUF_SIZE 32768
 #define MAX_IOV_SIZE MIN_CONST(IOV_MAX, 64)
@@ -255,6 +256,10 @@ static void qemu_iovec_release_ram(QEMUFile *f)
     memset(f->may_free, 0, sizeof(f->may_free));
 }
 
+bool qemu_file_is_seekable(QEMUFile *f)
+{
+    return qio_channel_has_feature(f->ioc, QIO_CHANNEL_FEATURE_SEEKABLE);
+}
 
 /**
  * Flushes QEMUFile buffer
@@ -447,6 +452,107 @@ void qemu_put_buffer(QEMUFile *f, const uint8_t *buf, size_t size)
     }
 }
 
+void qemu_put_buffer_at(QEMUFile *f, const uint8_t *buf, size_t buflen,
+                        off_t pos)
+{
+    Error *err = NULL;
+    size_t ret;
+
+    if (f->last_error) {
+        return;
+    }
+
+    qemu_fflush(f);
+    ret = qio_channel_pwrite(f->ioc, (char *)buf, buflen, pos, &err);
+
+    if (err) {
+        qemu_file_set_error_obj(f, -EIO, err);
+        return;
+    }
+
+    if ((ssize_t)ret == QIO_CHANNEL_ERR_BLOCK) {
+        qemu_file_set_error_obj(f, -EAGAIN, NULL);
+        return;
+    }
+
+    if (ret != buflen) {
+        error_setg(&err, "Partial write of size %zu, expected %zu", ret,
+                   buflen);
+        qemu_file_set_error_obj(f, -EIO, err);
+        return;
+    }
+
+    stat64_add(&mig_stats.qemu_file_transferred, buflen);
+
+    return;
+}
+
+
+size_t qemu_get_buffer_at(QEMUFile *f, const uint8_t *buf, size_t buflen,
+                          off_t pos)
+{
+    Error *err = NULL;
+    size_t ret;
+
+    if (f->last_error) {
+        return 0;
+    }
+
+    ret = qio_channel_pread(f->ioc, (char *)buf, buflen, pos, &err);
+
+    if ((ssize_t)ret == -1 || err) {
+        qemu_file_set_error_obj(f, -EIO, err);
+        return 0;
+    }
+
+    if ((ssize_t)ret == QIO_CHANNEL_ERR_BLOCK) {
+        qemu_file_set_error_obj(f, -EAGAIN, NULL);
+        return 0;
+    }
+
+    if (ret != buflen) {
+        error_setg(&err, "Partial read of size %zu, expected %zu", ret, buflen);
+        qemu_file_set_error_obj(f, -EIO, err);
+        return 0;
+    }
+
+    return ret;
+}
+
+void qemu_set_offset(QEMUFile *f, off_t off, int whence)
+{
+    Error *err = NULL;
+    off_t ret;
+
+    if (qemu_file_is_writable(f)) {
+        qemu_fflush(f);
+    } else {
+        /* Drop all cached buffers if existed; will trigger a re-fill later */
+        f->buf_index = 0;
+        f->buf_size = 0;
+    }
+
+    ret = qio_channel_io_seek(f->ioc, off, whence, &err);
+    if (ret == (off_t)-1) {
+        qemu_file_set_error_obj(f, -EIO, err);
+    }
+}
+
+off_t qemu_get_offset(QEMUFile *f)
+{
+    Error *err = NULL;
+    off_t ret;
+
+    qemu_fflush(f);
+
+    ret = qio_channel_io_seek(f->ioc, 0, SEEK_CUR, &err);
+    if (ret == (off_t)-1) {
+        qemu_file_set_error_obj(f, -EIO, err);
+    }
+    return ret;
+}
+
+
 void qemu_put_byte(QEMUFile *f, int v)
 {
     if (f->last_error) {