qemu/io, branch master

crypto: propagate errors from TLS session I/O callbacks

2024-07-24T09:39:10Z

GNUTLS doesn't know how to perform I/O on anything other than plain FDs, so the TLS session provides it with some I/O callbacks. The GNUTLS API design requires these callbacks to return a unix errno value, which means we're currently loosing the useful QEMU "Error" object. This changes the I/O callbacks in QEMU to stash the "Error" object in the QCryptoTLSSession class, and fetch it when seeing an I/O error returned from GNUTLS, thus preserving useful error messages. Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Daniel P. Berrangé

crypto: push error reporting into TLS session I/O APIs

2024-07-24T09:39:10Z

The current TLS session I/O APIs just return a synthetic errno value on error, which has been translated from a gnutls error value. This looses a large amount of valuable information that distinguishes different scenarios. Pushing population of the "Error *errp" object into the TLS session I/O APIs gives more detailed error information. Reviewed-by: Philippe Mathieu-Daudé Signed-off-by: Daniel P. Berrangé

qio: add support for SO_PEERCRED for socket channel

2024-07-22T11:47:41Z

The function qio_channel_get_peercred() returns a pointer to the credentials of the peer process connected to this socket. This credentials structure is defined in as follows: struct ucred { pid_t pid; /* Process ID of the sending process */ uid_t uid; /* User ID of the sending process */ gid_t gid; /* Group ID of the sending process */ }; The use of this function is possible only for connected AF_UNIX stream sockets and for AF_UNIX stream and datagram socket pairs. On platform other than Linux, the function return 0. Signed-off-by: Anthony Harivel Link: https://lore.kernel.org/r/20240522153453.1230389-2-aharivel@redhat.com Signed-off-by: Paolo Bonzini

Revert "meson: Propagate gnutls dependency"

2024-07-03T16:41:26Z

This reverts commit 3eacf70bb5a83e4775ad8003cbca63a40f70c8c2. It was only needed because of duplicate objects caused by declare_dependency(link_whole: ...), and can be dropped now that meson.build specifies objects and dependencies separately for the internal dependencies. Signed-off-by: Akihiko Odaki Message-ID: <20240524-objects-v1-2-07cbbe96166b@daynix.com> Signed-off-by: Paolo Bonzini

io: Stop using qemu_open_old in channel-file

2024-06-21T12:47:22Z

We want to make use of the Error object to report fdset errors from qemu_open_internal() and passing the error pointer to qemu_open_old() would require changing all callers. Move the file channel to the new API instead. Reviewed-by: Daniel P. Berrangé Reviewed-by: Peter Xu Signed-off-by: Fabiano Rosas

qio: Inherit follow_coroutine_ctx across TLS

2024-05-29T23:30:31Z

Since qemu 8.2, the combination of NBD + TLS + iothread crashes on an assertion failure: qemu-kvm: ../io/channel.c:534: void qio_channel_restart_read(void *): Assertion `qemu_get_current_aio_context() == qemu_coroutine_get_aio_context(co)' failed. It turns out that when we removed AioContext locking, we did so by having NBD tell its qio channels that it wanted to opt in to qio_channel_set_follow_coroutine_ctx(); but while we opted in on the main channel, we did not opt in on the TLS wrapper channel. qemu-iotests has coverage of NBD+iothread and NBD+TLS, but apparently no coverage of NBD+TLS+iothread, or we would have noticed this regression sooner. (I'll add that in the next patch) But while we could manually opt in to the TLS channel in nbd/server.c (a one-line change), it is more generic if all qio channels that wrap other channels inherit the follow status, in the same way that they inherit feature bits. CC: Stefan Hajnoczi CC: Daniel P. Berrangé CC: qemu-stable@nongnu.org Fixes: https://issues.redhat.com/browse/RHEL-34786 Fixes: 06e0f098 ("io: follow coroutine AioContext in qio_channel_yield()", v8.2.0) Signed-off-by: Eric Blake Reviewed-by: Stefan Hajnoczi Reviewed-by: Daniel P. Berrangé Message-ID: <20240518025246.791593-5-eblake@redhat.com>

io: Introduce qio_channel_file_new_dupfd

2024-03-12T19:22:23Z

Add a new helper function for creating a QIOChannelFile channel with a duplicated file descriptor. This saves the calling code from having to do error checking on the dup() call. Suggested-by: "Daniel P. Berrangé" Signed-off-by: Fabiano Rosas Reviewed-by: "Daniel P. Berrangé" Link: https://lore.kernel.org/r/20240311233335.17299-2-farosas@suse.de Signed-off-by: Peter Xu

migration/multifd: Don't fsync when closing QIOChannelFile

2024-03-11T18:41:40Z

Commit bc38feddeb ("io: fsync before closing a file channel") added a fsync/fdatasync at the closing point of the QIOChannelFile to ensure integrity of the migration stream in case of QEMU crash. The decision to do the sync at qio_channel_close() was not the best since that function runs in the main thread and the fsync can cause QEMU to hang for several minutes, depending on the migration size and disk speed. To fix the hang, remove the fsync from qio_channel_file_close(). At this moment, the migration code is the only user of the fsync and we're taking the tradeoff of not having a sync at all, leaving the responsibility to the upper layers. Fixes: bc38feddeb ("io: fsync before closing a file channel") Reviewed-by: "Daniel P. Berrangé" Signed-off-by: Fabiano Rosas Link: https://lore.kernel.org/r/20240305195629.9922-1-farosas@suse.de Link: https://lore.kernel.org/r/20240305174332.2553-1-farosas@suse.de [peterx: add more comment to the qio_channel_close()] Signed-off-by: Peter Xu

io: fsync before closing a file channel

2024-03-01T07:42:04Z

Make sure the data is flushed to disk before closing file channels. This is to ensure data is on disk and not lost in the event of a host crash. This is currently being implemented to affect the migration code when migrating to a file, but all QIOChannelFile users should benefit from the change. Reviewed-by: "Daniel P. Berrangé" Acked-by: "Daniel P. Berrangé" Signed-off-by: Fabiano Rosas Link: https://lore.kernel.org/r/20240229153017.2221-6-farosas@suse.de Signed-off-by: Peter Xu

io: implement io_pwritev/preadv for QIOChannelFile

2024-03-01T07:42:04Z

The upcoming 'mapped-ram' feature will require qemu to write data to (and restore from) specific offsets of the migration file. Add a minimal implementation of pwritev/preadv and expose them via the io_pwritev and io_preadv interfaces. Signed-off-by: Nikolay Borisov Reviewed-by: "Daniel P. Berrangé" Reviewed-by: Peter Xu Signed-off-by: Fabiano Rosas Link: https://lore.kernel.org/r/20240229153017.2221-5-farosas@suse.de Signed-off-by: Peter Xu