On 21.10.25 02:51, Raphael Norwitz wrote:
For now a naming nit and a question.
On Thu, Oct 16, 2025 at 7:44 AM Vladimir Sementsov-Ogievskiy
<[email protected]> wrote:
Signed-off-by: Vladimir Sementsov-Ogievskiy <[email protected]>
---
hw/virtio/vhost-user.c | 95 ++++++++++++++++++++++++++++++++++
include/hw/virtio/vhost-user.h | 4 ++
2 files changed, 99 insertions(+)
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
index c5cb5ed528..a820214188 100644
--- a/hw/virtio/vhost-user.c
+++ b/hw/virtio/vhost-user.c
@@ -28,6 +28,8 @@
#include "system/runstate.h"
#include "system/cryptodev.h"
#include "migration/postcopy-ram.h"
+#include "migration/qemu-file-types.h"
+#include "migration/qemu-file.h"
#include "trace.h"
#include "system/ramblock.h"
@@ -3137,6 +3139,99 @@ void vhost_user_qmp_status(struct vhost_dev *dev,
VirtioStatus *status)
qmp_decode_protocols(u->protocol_features);
}
+typedef struct VhostUserMigTmp {
+ struct vhost_dev *parent;
+ bool has_backend_channel;
+ int backend_fd;
+ uint32_t memory_slots;
+ uint64_t protocol_features;
+} VhostUserMigTmp;
+
+static int vhost_user_tmp_pre_save(void *opaque)
+{
+ VhostUserMigTmp *tmp = opaque;
+ struct vhost_dev *dev = tmp->parent;
+ struct vhost_user *u = dev->opaque;
+ QIOChannelSocket *sioc = u->backend_sioc;
+
+ if (sioc && sioc->fd < 0) {
+ return -EINVAL;
+ }
+
+ tmp->backend_fd = sioc ? sioc->fd : -1;
+ tmp->has_backend_channel = !!sioc;
+ tmp->memory_slots = u->user->memory_slots;
+ tmp->protocol_features = u->protocol_features;
+
+ return 0;
+}
+
+static int vhost_user_tmp_post_load(void *opaque, int version_id)
+{
+ struct VhostUserMigTmp *tmp = opaque;
+ struct vhost_dev *dev = tmp->parent;
+ struct vhost_user *u = dev->opaque;
+ Error *local_err = NULL;
+
+ if (tmp->has_backend_channel) {
+ u->backend_sioc = qio_channel_socket_new_fd(tmp->backend_fd,
+ &local_err);
+ if (!u->backend_sioc) {
+ error_report_err(local_err);
+ return -EINVAL;
+ }
+ u->backend_src = qio_channel_add_watch_source(
+ QIO_CHANNEL(u->backend_sioc), G_IO_IN | G_IO_HUP,
+ backend_read, u->dev, NULL, NULL);
+ }
+
+ u->user->memory_slots = tmp->memory_slots;
+ u->protocol_features = tmp->protocol_features;
+
+ return 0;
+}
+
+static bool vhost_user_tmp_test_fd(void *opaque, int version_id)
+{
+ struct VhostUserMigTmp *tmp = opaque;
+
+ return tmp->has_backend_channel;
+}
+
Will this be vhost-user-blk specific? It should probably be something
like vhost_user_backend_transfer_tmp?
Oh right. a mistake.
+static const VMStateDescription vmstate_vhost_user_blk_tmp = {
+ .name = "vhost-user-blk-tmp",
+ .pre_save = vhost_user_tmp_pre_save,
+ .post_load = vhost_user_tmp_post_load,
+ .fields = (const VMStateField[]) {
+ VMSTATE_UINT64(protocol_features, VhostUserMigTmp),
+ VMSTATE_UINT32(memory_slots, VhostUserMigTmp),
+ VMSTATE_BOOL(has_backend_channel, VhostUserMigTmp),
+ VMSTATE_FD_TEST(backend_fd, VhostUserMigTmp, vhost_user_tmp_test_fd),
+ VMSTATE_END_OF_LIST()
+ },
+};
+
+static int vhost_user_post_load(void *opaque, int version_id)
+{
+ struct vhost_dev *dev = opaque;
+ struct vhost_user *u = dev->opaque;
+
+ u->postcopy_notifier.notify = vhost_user_postcopy_notifier;
+ postcopy_add_notifier(&u->postcopy_notifier);
+
+ return 0;
+}
+
Why do we need a second post_load() callback here? Why can't
u->postcopy_notifier.notify be set in vhost_user_tmp_post_load()?
Hmm.. Yes, looks strange, I don't remember. Will try to merge.
+const VMStateDescription vmstate_vhost_user = {
+ .name = "vhost-user",
+ .post_load = vhost_user_post_load,
+ .fields = (const VMStateField[]) {
+ VMSTATE_WITH_TMP(struct vhost_dev, VhostUserMigTmp,
+ vmstate_vhost_user_blk_tmp),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
const VhostOps user_ops = {
.backend_type = VHOST_BACKEND_TYPE_USER,
.vhost_backend_init = vhost_user_backend_init,
diff --git a/include/hw/virtio/vhost-user.h b/include/hw/virtio/vhost-user.h
index 36d96296a3..fb89268de2 100644
--- a/include/hw/virtio/vhost-user.h
+++ b/include/hw/virtio/vhost-user.h
@@ -114,4 +114,8 @@ void vhost_user_async_close(DeviceState *d,
void vhost_user_qmp_status(struct vhost_dev *dev, VirtioStatus *status);
+extern const VMStateDescription vmstate_vhost_user;
+#define VMSTATE_BACKEND_TRANSFER_VHOST_USER(_field, _state) \
+ VMSTATE_STRUCT(_field, _state, 0, vmstate_vhost_user, struct vhost_dev)
+
#endif
--
2.48.1
--
Best regards,
Vladimir
