On Fri, 9 Jan 2026 at 18:12, Fabiano Rosas <[email protected]> wrote:
>
> Centralize, on both sides of migration, the setting of the to_src_file
> and from_dst_file QEMUFiles. This will clean up the interface with
> channel.c and rdma.c, allowing those files to stop dealing with
> QEMUFile themselves.
>
> (multifd_recv_new_channel was changed to return bool+errp for
> convenience)
>
> Reviewed-by: Peter Xu <[email protected]>
> Signed-off-by: Fabiano Rosas <[email protected]>
> ---
> migration/channel.c | 9 +----
> migration/migration.c | 84 ++++++++++++++++++++++++++-----------------
> migration/migration.h | 2 ++
> migration/multifd.c | 8 +++--
> migration/multifd.h | 2 +-
> 5 files changed, 61 insertions(+), 44 deletions(-)
>
> diff --git a/migration/channel.c b/migration/channel.c
> index 26cb7bf059..6acce7b2a2 100644
> --- a/migration/channel.c
> +++ b/migration/channel.c
> @@ -14,7 +14,6 @@
> #include "channel.h"
> #include "tls.h"
> #include "migration.h"
> -#include "qemu-file.h"
> #include "trace.h"
> #include "qapi/error.h"
> #include "io/channel-tls.h"
> @@ -80,14 +79,8 @@ void migration_channel_connect(MigrationState *s,
> QIOChannel *ioc)
> return;
> }
>
> - QEMUFile *f = qemu_file_new_output(ioc);
> -
> migration_ioc_register_yank(ioc);
> -
> - qemu_mutex_lock(&s->qemu_file_lock);
> - s->to_dst_file = f;
> - qemu_mutex_unlock(&s->qemu_file_lock);
> -
> + migration_outgoing_setup(ioc);
> migration_connect(s);
> }
>
> diff --git a/migration/migration.c b/migration/migration.c
> index 1ea6125454..b7367eb5cf 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -930,17 +930,56 @@ out:
> migrate_incoming_unref_outgoing_state();
> }
>
> -/**
> - * migration_incoming_setup: Setup incoming migration
> - * @f: file for main migration channel
> +static bool migration_has_main_and_multifd_channels(void);
> +
> +/*
> + * Returns whether all the necessary channels to proceed with the
> + * incoming migration have been established without error.
> */
> -static void migration_incoming_setup(QEMUFile *f)
> +bool migration_incoming_setup(QIOChannel *ioc, uint8_t channel, Error **errp)
> {
> MigrationIncomingState *mis = migration_incoming_get_current();
> + QEMUFile *f;
>
> - assert(!mis->from_src_file);
> - mis->from_src_file = f;
> - qemu_file_set_blocking(f, false, &error_abort);
> + if (multifd_recv_setup(errp) != 0) {
> + return false;
> + }
> +
> + switch (channel) {
> + case CH_MAIN:
> + f = qemu_file_new_input(ioc);
> + assert(!mis->from_src_file);
> + mis->from_src_file = f;
> + qemu_file_set_blocking(f, false, &error_abort);
> + break;
> +
> + case CH_MULTIFD:
> + if (!multifd_recv_new_channel(ioc, errp)) {
> + return false;
> + }
> + break;
> +
> + case CH_POSTCOPY:
> + assert(!mis->postcopy_qemufile_dst);
> + f = qemu_file_new_input(ioc);
> + postcopy_preempt_new_channel(mis, f);
> + return false;
> +
> + default:
> + g_assert_not_reached();
> + }
> +
> + return migration_has_main_and_multifd_channels();
> +}
> +
> +void migration_outgoing_setup(QIOChannel *ioc)
> +{
> + MigrationState *s = migrate_get_current();
> + QEMUFile *f = qemu_file_new_output(ioc);
> +
> + qemu_mutex_lock(&s->qemu_file_lock);
> + s->to_dst_file = f;
> + qemu_mutex_unlock(&s->qemu_file_lock);
> }
* Shouldn't migration_outgoing_setup() also return bool, to be
consistent with migration_incoming_setup() above? OR make
migration_incoming_setup() return void.
> /* Returns true if recovered from a paused migration, otherwise false */
> @@ -988,7 +1027,11 @@ void migration_incoming_process(void)
>
> void migration_fd_process_incoming(QEMUFile *f)
> {
> - migration_incoming_setup(f);
> + MigrationIncomingState *mis = migration_incoming_get_current();
> +
> + assert(!mis->from_src_file);
> + mis->from_src_file = f;
> + qemu_file_set_blocking(f, false, &error_abort);
> migration_incoming_process();
> }
* Is it possible to move above mis->from_src_file = f part to
migration_incoming_setup()?
> @@ -1011,8 +1054,6 @@ static bool
> migration_has_main_and_multifd_channels(void)
> void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp)
> {
> MigrationIncomingState *mis = migration_incoming_get_current();
> - Error *local_err = NULL;
> - QEMUFile *f;
> uint8_t channel;
> uint32_t channel_magic = 0;
> int ret = 0;
> @@ -1066,28 +1107,7 @@ void migration_ioc_process_incoming(QIOChannel *ioc,
> Error **errp)
> channel = CH_POSTCOPY;
> }
>
> - if (multifd_recv_setup(errp) != 0) {
> - return;
> - }
> -
> - if (channel == CH_MAIN) {
> - f = qemu_file_new_input(ioc);
> - migration_incoming_setup(f);
> - } else if (channel == CH_MULTIFD) {
> - /* Multiple connections */
> - multifd_recv_new_channel(ioc, &local_err);
> - if (local_err) {
> - error_propagate(errp, local_err);
> - return;
> - }
> - } else if (channel == CH_POSTCOPY) {
> - assert(!mis->postcopy_qemufile_dst);
> - f = qemu_file_new_input(ioc);
> - postcopy_preempt_new_channel(mis, f);
> - return;
> - }
> -
> - if (migration_has_main_and_multifd_channels()) {
> + if (migration_incoming_setup(ioc, channel, errp)) {
> migration_incoming_process();
> }
> }
> diff --git a/migration/migration.h b/migration/migration.h
> index d134881eaf..4dcf299719 100644
> --- a/migration/migration.h
> +++ b/migration/migration.h
> @@ -530,6 +530,8 @@ void migrate_set_state(MigrationStatus *state,
> MigrationStatus old_state,
> void migration_fd_process_incoming(QEMUFile *f);
> void migration_ioc_process_incoming(QIOChannel *ioc, Error **errp);
> void migration_incoming_process(void);
> +bool migration_incoming_setup(QIOChannel *ioc, uint8_t channel, Error
> **errp);
> +void migration_outgoing_setup(QIOChannel *ioc);
>
> bool migration_has_all_channels(void);
>
> diff --git a/migration/multifd.c b/migration/multifd.c
> index 3fb1a07ba9..4980ed4f04 100644
> --- a/migration/multifd.c
> +++ b/migration/multifd.c
> @@ -1521,7 +1521,7 @@ bool multifd_recv_all_channels_created(void)
> * Try to receive all multifd channels to get ready for the migration.
> * Sets @errp when failing to receive the current channel.
> */
> -void multifd_recv_new_channel(QIOChannel *ioc, Error **errp)
> +bool multifd_recv_new_channel(QIOChannel *ioc, Error **errp)
> {
> MultiFDRecvParams *p;
> Error *local_err = NULL;
> @@ -1536,7 +1536,7 @@ void multifd_recv_new_channel(QIOChannel *ioc, Error
> **errp)
> "failed to receive packet"
> " via multifd channel %d: ",
>
> qatomic_read(&multifd_recv_state->count));
> - return;
> + return false;
> }
> trace_multifd_recv_new_channel(id);
> } else {
> @@ -1549,7 +1549,7 @@ void multifd_recv_new_channel(QIOChannel *ioc, Error
> **errp)
> id);
> multifd_recv_terminate_threads(error_copy(local_err));
> error_propagate(errp, local_err);
> - return;
> + return false;
> }
> p->c = ioc;
> object_ref(OBJECT(ioc));
> @@ -1558,4 +1558,6 @@ void multifd_recv_new_channel(QIOChannel *ioc, Error
> **errp)
> qemu_thread_create(&p->thread, p->name, multifd_recv_thread, p,
> QEMU_THREAD_JOINABLE);
> qatomic_inc(&multifd_recv_state->count);
> +
> + return true;
> }
> diff --git a/migration/multifd.h b/migration/multifd.h
> index 9b6d81e7ed..89a395aef2 100644
> --- a/migration/multifd.h
> +++ b/migration/multifd.h
> @@ -42,7 +42,7 @@ int multifd_recv_setup(Error **errp);
> void multifd_recv_cleanup(void);
> void multifd_recv_shutdown(void);
> bool multifd_recv_all_channels_created(void);
> -void multifd_recv_new_channel(QIOChannel *ioc, Error **errp);
> +bool multifd_recv_new_channel(QIOChannel *ioc, Error **errp);
> void multifd_recv_sync_main(void);
> int multifd_send_sync_main(MultiFDSyncReq req);
> bool multifd_queue_page(RAMBlock *block, ram_addr_t offset);
> --
* Change looks okay.
Reviewed-by: Prasad Pandit <[email protected]>
Thank you.
---
- Prasad
