Re: [PATCH v6 0/2] check magic value for deciding the mapping of channels

["manish.mishra" <manish.mishra@nutanix.com>]

[-- Attachment #1: Type: text/plain, Size: 4052 bytes --]

Hi Peter, Daniel,

Just a gentle reminder on this patch if it can be merged, and really sorry i see now earlier reminders i sent were on v6[0/2] and somehow you were not CCed on that earlier. You were CCed just on v6[1/2] and v6[2,2] so that's why probably missed it.

Thanks

Manish Mishra

On 21/12/22 12:06 am, manish.mishra wrote:
> Current logic assumes that channel connections on the destination side are
> always established in the same order as the source and the first one will
> always be the main channel followed by the multifid or post-copy
> preemption channel. This may not be always true, as even if a channel has a
> connection established on the source side it can be in the pending state on
> the destination side and a newer connection can be established first.
> Basically causing out of order mapping of channels on the destination side.
> Currently, all channels except post-copy preempt send a magic number, this
> patch uses that magic number to decide the type of channel. This logic is
> applicable only for precopy(multifd) live migration, as mentioned, the
> post-copy preempt channel does not send any magic number. Also, tls live
> migrations already does tls handshake before creating other channels, so
> this issue is not possible with tls, hence this logic is avoided for tls
> live migrations. This patch uses MSG_PEEK to check the magic number of
> channels so that current data/control stream management remains
> un-effected.
>
> v2:
>    TLS does not support MSG_PEEK, so V1 was broken for tls live
>    migrations. For tls live migration, while initializing main channel
>    tls handshake is done before we can create other channels, so this
>    issue is not possible for tls live migrations. In V2 added a check
>    to avoid checking magic number for tls live migration and fallback
>    to older method to decide mapping of channels on destination side.
>
> v3:
>    1. Split change in two patches, io patch for read_peek routines,
>       migration patch for migration related changes.
>    2. Add flags to io_readv calls to get extra read flags like
>       MSG_PEEK.
>    3. Some other minor fixes.
>
> v4:
>    1. Removed common *all_eof routines for read peek and added one
>       specific to live migration.
>    2. Updated to use qemu_co_sleep_ns instead of qio_channel_yield.
>    3. Some other minor fixes.
>
> v5:
>    1. Handle busy-wait in migration_channel_read_peek due partial reads.
>
> v6:
>    With earlier patch, multifd_load_setup was done only in
>    migration_incoming_setup but if multifd channel is received before
>    default channel, multifd channels will be uninitialized. Moved
>    multifd_load_setup to migration_ioc_process_incoming.
>    
>
> manish.mishra (2):
>    io: Add support for MSG_PEEK for socket channel
>    migration: check magic value for deciding the mapping of channels
>
>   chardev/char-socket.c               |  4 +--
>   include/io/channel.h                |  6 ++++
>   io/channel-buffer.c                 |  1 +
>   io/channel-command.c                |  1 +
>   io/channel-file.c                   |  1 +
>   io/channel-null.c                   |  1 +
>   io/channel-socket.c                 | 17 ++++++++-
>   io/channel-tls.c                    |  1 +
>   io/channel-websock.c                |  1 +
>   io/channel.c                        | 16 ++++++---
>   migration/channel-block.c           |  1 +
>   migration/channel.c                 | 45 ++++++++++++++++++++++++
>   migration/channel.h                 |  5 +++
>   migration/migration.c               | 54 ++++++++++++++++++++---------
>   migration/multifd.c                 | 19 +++++-----
>   migration/multifd.h                 |  2 +-
>   migration/postcopy-ram.c            |  5 +--
>   migration/postcopy-ram.h            |  2 +-
>   scsi/qemu-pr-helper.c               |  2 +-
>   tests/qtest/tpm-emu.c               |  2 +-
>   tests/unit/test-io-channel-socket.c |  1 +
>   util/vhost-user-server.c            |  2 +-
>   22 files changed, 148 insertions(+), 41 deletions(-)
>

[-- Attachment #2: Type: text/html, Size: 4360 bytes --]