This reverts commit a7f523c7d1.
The nested event loop is broken by design. It's only user was removed.
Drop the code as well so that nobody ever tries to use it again.
I had to fix a couple of trivial conflicts around return values because
of 025faa872b ("vhost-user: stick to -errno error return convention").
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20230119172424.478268-3-groug@kaod.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Maxime Coquelin <maxime.coquelin@redhat.com>
(cherry picked from commit 4382138f64)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
This reverts commit db8a3772e3.
Motivation : this is breaking vhost-user with DPDK as reported in [0].
Received unexpected msg type. Expected 22 received 40
Fail to update device iotlb
Received unexpected msg type. Expected 40 received 22
Received unexpected msg type. Expected 22 received 11
Fail to update device iotlb
Received unexpected msg type. Expected 11 received 22
vhost VQ 1 ring restore failed: -71: Protocol error (71)
Received unexpected msg type. Expected 22 received 11
Fail to update device iotlb
Received unexpected msg type. Expected 11 received 22
vhost VQ 0 ring restore failed: -71: Protocol error (71)
unable to start vhost net: 71: falling back on userspace virtio
The failing sequence that leads to the first error is :
- QEMU sends a VHOST_USER_GET_STATUS (40) request to DPDK on the master
socket
- QEMU starts a nested event loop in order to wait for the
VHOST_USER_GET_STATUS response and to be able to process messages from
the slave channel
- DPDK sends a couple of legitimate IOTLB miss messages on the slave
channel
- QEMU processes each IOTLB request and sends VHOST_USER_IOTLB_MSG (22)
updates on the master socket
- QEMU assumes to receive a response for the latest VHOST_USER_IOTLB_MSG
but it gets the response for the VHOST_USER_GET_STATUS instead
The subsequent errors have the same root cause : the nested event loop
breaks the order by design. It lures QEMU to expect responses to the
latest message sent on the master socket to arrive first.
Since this was only needed for DAX enablement which is still not merged
upstream, just drop the code for now. A working solution will have to
be merged later on. Likely protect the master socket with a mutex
and service the slave channel with a separate thread, as discussed with
Maxime in the mail thread below.
[0] https://lore.kernel.org/qemu-devel/43145ede-89dc-280e-b953-6a2b436de395@redhat.com/
Reported-by: Yanghang Liu <yanghliu@redhat.com>
Buglink: https://bugzilla.redhat.com/show_bug.cgi?id=2155173
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20230119172424.478268-2-groug@kaod.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Stefan Hajnoczi <stefanha@redhat.com>
Acked-by: Maxime Coquelin <maxime.coquelin@redhat.com>
(cherry picked from commit f340a59d5a)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
During protocol negotiation, when we the QEMU
stub does not support a backend with F_CONFIG,
it throws a warning and supresses the
VHOST_USER_PROTOCOL_F_CONFIG bit.
However, the warning uses warn_reportf_err macro
and passes an unitialized errp pointer. However,
the macro tries to edit the 'msg' member of the
unitialized Error and segfaults.
Instead, just use warn_report, which prints a
warning message directly to the output.
Fixes: 5653493 ("hw/virtio/vhost-user: don't suppress F_CONFIG when supported")
Signed-off-by: Albert Esteve <aesteve@redhat.com>
Message-Id: <20230302121719.9390-1-aesteve@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
(cherry picked from commit 90e31232cf)
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
..and use for both virtio-user-blk and virtio-user-gpio. This avoids
the circular close by deferring shutdown due to disconnection until a
later point. virtio-user-blk already had this mechanism in place so
generalise it as a vhost-user helper function and use for both blk and
gpio devices.
While we are at it we also fix up vhost-user-gpio to re-establish the
event handler after close down so we can reconnect later.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20221130112439.2527228-5-alex.bennee@linaro.org>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
The motivation of adding vhost-user vhost_dev_start support is to
improve backend configuration speed and reduce live migration VM
downtime.
Today VQ configuration is issued one by one. For virtio net with
multi-queue support, backend needs to update RSS (Receive side
scaling) on every rx queue enable. Updating RSS is time-consuming
(typical time like 7ms).
Implement already defined vhost status and message in the vhost
specification [1].
(a) VHOST_USER_PROTOCOL_F_STATUS
(b) VHOST_USER_SET_STATUS
(c) VHOST_USER_GET_STATUS
Send message VHOST_USER_SET_STATUS with VIRTIO_CONFIG_S_DRIVER_OK for
device start and reset(0) for device stop.
On reception of the DRIVER_OK message, backend can apply the needed setting
only once (instead of incremental) and also utilize parallelism on enabling
queues.
This improves QEMU's live migration downtime with vhost user backend
implementation by great margin, specially for the large number of VQs of 64
from 800 msec to 250 msec.
[1] https://qemu-project.gitlab.io/qemu/interop/vhost-user.html
Signed-off-by: Yajun Wu <yajunw@nvidia.com>
Acked-by: Parav Pandit <parav@nvidia.com>
Message-Id: <20221017064452.1226514-3-yajunw@nvidia.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
vhost backend sends host notification for every VQ. If backend creates
VQs in parallel, the VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG may
arrive to QEMU in different order than incremental queue index order.
For example VQ 1's message arrive earlier than VQ 0's:
After alloc VhostUserHostNotifier for VQ 1. GPtrArray becomes
[ nil, VQ1 pointer ]
After alloc VhostUserHostNotifier for VQ 0. GPtrArray becomes
[ VQ0 pointer, nil, VQ1 pointer ]
This is wrong. fetch_notifier will return NULL for VQ 1 in
vhost_user_get_vring_base, causes host notifier miss removal(leak).
The fix is to remove current element from GPtrArray, make the right
position for element to insert.
Fixes: 503e355465 ("virtio/vhost-user: dynamically assign VhostUserHostNotifiers")
Signed-off-by: Yajun Wu <yajunw@nvidia.com>
Acked-by: Parav Pandit <parav@nvidia.com>
Message-Id: <20221018023651.1359420-1-yajunw@nvidia.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20220802095010.3330793-8-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
There are some extra bits used over a vhost-user connection which are
hidden from the device itself. We need to set them here to ensure we
enable things like the protocol extensions.
Currently net/vhost-user.c has it's own inscrutable way of persisting
this data but it really should live in the core vhost_user code.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220726192150.2435175-7-alex.bennee@linaro.org>
Message-Id: <20220802095010.3330793-2-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
As the close-on-exec flags is not set on the file descriptors returned
by socketpair() at default, the fds will survive across exec' function.
In the case that exec' function get invoked, such as the live-update feature
which is been developing, it will cause fd leaks.
To address this problem, we should call qemu_socketpair() to create an pair of
connected sockets with the close-on-exec flag set.
Signed-off-by: Guoyi Tu <tugy@chinatelecom.cn>
Reviewed-by: Christian Schoenebeck <qemu_oss@crudebyte.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <7002b12a5fb0a30cd878e14e07da61c36da72913.1661240709.git.tugy@chinatelecom.cn>
As reads happen in the callback we were never seeing them. We only
really care about the header so move the tracepoint to when the header
is complete.
Fixes: 6ca6d8ee9d (hw/virtio: add vhost_user_[read|write] trace points)
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20220728135503.1060062-5-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Kernel and user vhost may report virtqueue errors via eventfd.
This is only reliable way to get notification about protocol error.
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Message-Id: <20220623161325.18813-2-vsementsov@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Roman Kagan <rvkagan@yandex-team.ru>
In fetch_or_create_notifier, idx begins with 0. So the GPtrArray size
should be idx + 1 and g_ptr_array_set_size should be called with idx + 1.
This wrong GPtrArray size causes fetch_or_create_notifier return an invalid
address. Passing this invalid pointer to vhost_user_host_notifier_remove
causes assert fail:
qemu/include/qemu/int128.h:27: int128_get64: Assertion `r == a' failed.
shutting down, reason=crashed
Backends like dpdk-vdpa which sends out vhost notifier requests almost always
hit qemu crash.
Fixes: 503e355465 ("virtio/vhost-user: dynamically assign VhostUserHostNotifiers")
Signed-off-by: Yajun Wu <yajunw@nvidia.com>
Acked-by: Parav Pandit <parav@nvidia.com>
Change-Id: I87e0f7591ca9a59d210879b260704a2d9e9d6bcd
Message-Id: <20220526034851.683258-1-yajunw@nvidia.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Eddie Dong <eddie.dong@intel.com>
Variable `vdev` in `struct vhost_dev` will not be ready
until start the device, so let's not use it for the error
output here.
Fixes: 5653493 ("hw/virtio/vhost-user: don't suppress F_CONFIG when supported")
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
Message-Id: <20220525125540.50979-1-changpeng.liu@intel.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Fixes: 5653493 ("hw/virtio/vhost-user: don't suppress F_CONFIG when supported")
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
Fixes: 5653493 ("hw/virtio/vhost-user: don't suppress F_CONFIG when supported")
Signed-off-by: Changpeng Liu <changpeng.liu@intel.com>
At a couple of hundred bytes per notifier allocating one for every
potential queue is very wasteful as most devices only have a few
queues. Instead of having this handled statically dynamically assign
them and track in a GPtrArray.
[AJB: it's hard to trigger the vhost notifiers code, I assume as it
requires a KVM guest with appropriate backend]
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220321153037.3622127-14-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Previously we would silently suppress VHOST_USER_PROTOCOL_F_CONFIG
during the protocol negotiation if the QEMU stub hadn't implemented
the vhost_dev_config_notifier. However this isn't the only way we can
handle config messages, the existing vdc->get/set_config can do this
as well.
Lightly re-factor the code to check for both potential methods and
instead of silently squashing the feature error out. It is unlikely
that a vhost-user backend expecting to handle CONFIG messages will
behave correctly if they never get sent.
Fixes: 1c3e5a2617 ("vhost-user: back SET/GET_CONFIG requests with a protocol feature")
Cc: Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220321153037.3622127-13-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
These are useful when trying to debug the initial vhost-user
negotiation, especially when it hard to get logging from the low level
library on the other side.
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220321153037.3622127-4-alex.bennee@linaro.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
The correct name of the macro is TARGET_PPC64.
Fixes: 27598393a2 ("Lift max memory slots limit imposed by vhost-user")
Reported-by: Fabiano Rosas <farosas@linux.ibm.com>
Signed-off-by: Murilo Opsfelder Araujo <muriloo@linux.ibm.com>
Cc: Raphael Norwitz <raphael.norwitz@nutanix.com>
Cc: Peter Turschmid <peter.turschm@nutanix.com>
Reviewed-by: Daniel Henrique Barboza <danielhb413@gmail.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20220503180108.34506-1-muriloo@linux.ibm.com>
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
The spec clarifies now that QEMU should not send a file descriptor in a
request to remove a memory region. Change it accordingly.
For libvhost-user, this is a bug fix that makes it compatible with
rust-vmm's implementation that doesn't send a file descriptor. Keep
accepting, but ignoring a file descriptor for compatibility with older
QEMU versions.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20220407133657.155281-4-kwolf@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
The qemu_*block() functions are meant to be be used with sockets (the
win32 implementation expects SOCKET)
Over time, those functions where used with Win32 SOCKET or
file-descriptors interchangeably. But for portability, they must only be
used with socket-like file-descriptors. FDs can use
g_unix_set_fd_nonblocking() instead.
Rename the functions with "socket" in the name to prevent bad usages.
This is effectively reverting commit f9e8cacc55 ("oslib-posix:
rename socket_set_nonblock() to qemu_set_nonblock()").
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Replace the global variables with inlined helper functions. getpagesize() is very
likely annotated with a "const" function attribute (at least with glibc), and thus
optimization should apply even better.
This avoids the need for a constructor initialization too.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Message-Id: <20220323155743.1585078-12-marcandre.lureau@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When vhost-user device cleanup, remove notifier MR and munmaps notifier
address in the event-handling thread, VM CPU thread writing the notifier
in concurrent fails with an error of accessing invalid address. It
happens because MR is still being referenced and accessed in another
thread while the underlying notifier mmap address is being freed and
becomes invalid.
This patch calls RCU and munmap notifiers in the callback after the
memory flatview update finish.
Fixes: 44866521bd ("vhost-user: support registering external host notifiers")
Cc: qemu-stable@nongnu.org
Signed-off-by: Xueming Li <xuemingl@nvidia.com>
Message-Id: <20220207071929.527149-3-xuemingl@nvidia.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Notifier set when vhost-user backend asks qemu to mmap an FD and
offset. When vhost-user backend restart or getting killed, VQ notifier
FD and mmap addresses become invalid. After backend restart, MR contains
the invalid address will be restored and fail on notifier access.
On the other hand, qemu should munmap the notifier, release underlying
hardware resources to enable backend restart and allocate hardware
notifier resources correctly.
Qemu shouldn't reference and use resources of disconnected backend.
This patch removes VQ notifier restore, uses the default vhost-user
notifier to avoid invalid address access.
After backend restart, the backend should ask qemu to install a hardware
notifier if needed.
Fixes: 44866521bd ("vhost-user: support registering external host notifiers")
Cc: qemu-stable@nongnu.org
Signed-off-by: Xueming Li <xuemingl@nvidia.com>
Message-Id: <20220207071929.527149-2-xuemingl@nvidia.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
VhostOps methods in user_ops are not very consistent in their error
returns: some return negated errno while others just -1.
Make sure all of them consistently return negated errno. This also
helps error propagation from the functions being called inside.
Besides, this synchronizes the error return convention with the other
two vhost backends, kernel and vdpa, and will therefore allow for
consistent error propagation in the generic vhost code (in a followup
patch).
Signed-off-by: Roman Kagan <rvkagan@yandex-team.ru>
Message-Id: <20211111153354.18807-9-rvkagan@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
In case of device resume after suspend, VQ notifier MR still valid.
Duplicated registrations explode memory block list and slow down device
resume.
Fixes: 44866521bd ("vhost-user: support registering external host notifiers")
Cc: tiwei.bie@intel.com
Cc: qemu-stable@nongnu.org
Cc: Yuwei Zhang <zhangyuwei.9149@bytedance.com>
Signed-off-by: Xueming Li <xuemingl@nvidia.com>
Message-Id: <20211008080215.590292-1-xuemingl@nvidia.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Qemu will crash on vhost backend unexpected exit and re-connect │
in some case due to access released memory.
Signed-off-by: Yuwei Zhang <zhangyuwei.9149@bytedance.com>
Message-Id: <20210830123433.45727-1-zhangyuwei.9149@bytedance.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
This would previously give error messages like
> Received unexpected msg type.Expected 0 received 1
Signed-off-by: Alyssa Ross <hi@alyssa.is>
Message-Id: <20210806143926.315725-1-hi@alyssa.is>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
On vhost-user-blk migration, qemu normally sends a number of commands
to enable logging if VHOST_USER_PROTOCOL_F_LOG_SHMFD is negotiated.
Qemu sends VHOST_USER_SET_FEATURES to enable buffers logging and
VHOST_USER_SET_VRING_ADDR per each started ring to enable "used ring"
data logging.
The issue is that qemu doesn't wait for reply from the vhost daemon
for these commands which may result in races between qemu expectation
of logging starting and actual login starting in vhost daemon.
The race can appear as follows: on migration setup, qemu enables dirty page
logging by sending VHOST_USER_SET_FEATURES. The command doesn't arrive to a
vhost-user-blk daemon immediately and the daemon needs some time to turn the
logging on internally. If qemu doesn't wait for reply, after sending the
command, qemu may start migrateing memory pages to a destination. At this time,
the logging may not be actually turned on in the daemon but some guest pages,
which the daemon is about to write to, may have already been transferred
without logging to the destination. Since the logging wasn't turned on,
those pages won't be transferred again as dirty. So we may end up with
corrupted data on the destination.
The same scenario is applicable for "used ring" data logging, which is
turned on with VHOST_USER_SET_VRING_ADDR command.
To resolve this issue, this patch makes qemu wait for the command result
explicitly if VHOST_USER_PROTOCOL_F_REPLY_ACK is negotiated and logging enabled.
Signed-off-by: Denis Plotnikov <den-plotnikov@yandex-team.ru>
Message-Id: <20210809104824.78830-1-den-plotnikov@yandex-team.ru>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
If call virtio_queue_set_host_notifier_mr fails, should free
host-notifier memory-region.
Fixes: 44866521bd ("vhost-user: support registering external host notifiers")
Signed-off-by: Yajun Wu <yajunw@nvidia.com>
Message-Id: <1629077555-19907-1-git-send-email-yajunw@nvidia.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
vhost_user_backend_init() can fail without setting an error. Unclean.
Its caller vhost_dev_init() compensates by substituting a generic
error then. Goes back to commit 28770ff935 "vhost: Distinguish errors
in vhost_backend_init()".
Clean up by moving the generic error from vhost_dev_init() to all the
failure paths that neglect to set an error.
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20210720125408.387910-14-armbru@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
vhost_user_get_config() can fail without setting an error. Unclean.
Its caller vhost_dev_get_config() compensates by substituting a
generic error then. Goes back to commit 50de51387f "vhost:
Distinguish errors in vhost_dev_get_config()".
Clean up by moving the generic error from vhost_dev_get_config() to
all the failure paths that neglect to set an error.
Cc: Kevin Wolf <kwolf@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20210720125408.387910-13-armbru@redhat.com>
Acked-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
[Sign of error_setg_errno()'s second argument fixed in both calls]
Since commit 9894dc0cdc "char: convert
from GIOChannel to QIOChannel", the first argument to the watch callback
can actually be a QIOChannel, which is not a GIOChannel (but a QEMU
Object).
Even though we never used that pointer, change the callback type to warn
the users. Possibly a better fix later, we may want to store the
callback and call it from intermediary functions.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
dev->max_queues was never initialised for backends that don't support
VHOST_USER_PROTOCOL_F_MQ, so it would use 0 as the maximum number of
queues to check against and consequently fail for any such backend.
Set it to 1 if the backend doesn't have multiqueue support.
Fixes: c90bd505a3
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210705171429.29286-1-kwolf@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Instead of just returning 0/-1 and letting the caller make up a
meaningless error message, add an Error parameter to allow reporting the
real error and switch to 0/-errno so that different kind of errors can
be distinguished in the caller.
config_len in vhost_user_get_config() is defined by the device, so if
it's larger than VHOST_USER_MAX_CONFIG_SIZE, this is a programming
error. Turn the corresponding check into an assertion.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210609154658.350308-6-kwolf@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Instead of just returning 0/-1 and letting the caller make up a
meaningless error message, switch to 0/-errno so that different kinds of
errors can be distinguished in the caller.
This involves changing a few more callbacks in VhostOps to return
0/-errno: .vhost_set_owner(), .vhost_get_features() and
.vhost_virtqueue_set_busyloop_timeout(). The implementations of these
functions are trivial as they generally just send a message to the
backend.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210609154658.350308-4-kwolf@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Instead of just returning 0/-1 and letting the caller make up a
meaningless error message, add an Error parameter to allow reporting the
real error and switch to 0/-errno so that different kind of errors can
be distinguished in the caller.
Specifically, in vhost-user, EPROTO is used for all errors that relate
to the connection itself, whereas other error codes are used for errors
relating to the content of the connection. This will allow us later to
automatically reconnect when the connection goes away, without ending up
in an endless loop if it's a permanent error in the configuration.
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20210609154658.350308-3-kwolf@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Creating a device with a number of queues that isn't supported by the
backend is pointless, the device won't work properly and the error
messages are rather confusing.
Just fail to create the device if num-queues is higher than what the
backend supports.
Since the relationship between num-queues and the number of virtqueues
depends on the specific device, this is an additional value that needs
to be initialised by the device. For convenience, allow leaving it 0 if
the check should be skipped. This makes sense for vhost-user-net where
separate vhost devices are used for the queues and custom initialisation
code is needed to perform the check.
Fixes: https://bugzilla.redhat.com/show_bug.cgi?id=1935031
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <20210429171316.162022-7-kwolf@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Now that everything is in place, have the nested event loop to monitor
the slave channel. The source in the main event loop is destroyed and
recreated to ensure any pending even for the slave channel that was
previously detected is purged. This guarantees that the main loop
wont invoke slave_read() based on an event that was already handled
by the nested loop.
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20210312092212.782255-7-groug@kaod.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
A deadlock condition potentially exists if a vhost-user process needs
to request something to QEMU on the slave channel while processing a
vhost-user message.
This doesn't seem to affect any vhost-user implementation so far, but
this is currently biting the upcoming enablement of DAX with virtio-fs.
The issue is being observed when the guest does an emergency reboot while
a mapping still exits in the DAX window, which is very easy to get with
a busy enough workload (e.g. as simulated by blogbench [1]) :
- QEMU sends VHOST_USER_GET_VRING_BASE to virtiofsd.
- In order to complete the request, virtiofsd then asks QEMU to remove
the mapping on the slave channel.
All these dialogs are synchronous, hence the deadlock.
As pointed out by Stefan Hajnoczi:
When QEMU's vhost-user master implementation sends a vhost-user protocol
message, vhost_user_read() does a "blocking" read during which slave_fd
is not monitored by QEMU.
The natural solution for this issue is an event loop. The main event
loop cannot be nested though since we have no guarantees that its
fd handlers are prepared for re-entrancy.
Introduce a new event loop that only monitors the chardev I/O for now
in vhost_user_read() and push the actual reading to a one-shot handler.
A subsequent patch will teach the loop to monitor and process messages
from the slave channel as well.
[1] https://github.com/jedisct1/Blogbench
Suggested-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20210312092212.782255-6-groug@kaod.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
The slave channel is implemented with socketpair() : QEMU creates
the pair, passes one of the socket to virtiofsd and monitors the
other one with the main event loop using qemu_set_fd_handler().
In order to fix a potential deadlock between QEMU and a vhost-user
external process (e.g. virtiofsd with DAX), we want to be able to
monitor and service the slave channel while handling vhost-user
requests.
Prepare ground for this by converting the slave channel to be a
QIOChannelSocket. This will make monitoring of the slave channel
as simple as calling qio_channel_add_watch_source(). Since the
connection is already established between the two sockets, only
incoming I/O (G_IO_IN) and disconnect (G_IO_HUP) need to be
serviced.
This also allows to get rid of the ancillary data parsing since
QIOChannelSocket can do this for us. Note that the MSG_CTRUNC
check is dropped on the way because QIOChannelSocket ignores this
case. This isn't a problem since slave_read() provisions space for
8 file descriptors, but affected vhost-user slave protocol messages
generally only convey one. If for some reason a buggy implementation
passes more file descriptors, no need to break the connection, just
like we don't break it if some other type of ancillary data is
received : this isn't explicitely violating the protocol per-se so
it seems better to ignore it.
The current code errors out on short reads and writes. Use the
qio_channel_*_all() variants to address this on the way.
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20210312092212.782255-5-groug@kaod.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20210312092212.782255-4-groug@kaod.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Some message types, e.g. VHOST_USER_SLAVE_VRING_HOST_NOTIFIER_MSG,
can convey file descriptors. These must be closed before returning
from slave_read() to avoid being leaked. This can currently be done
in two different places:
[1] just after the request has been processed
[2] on the error path, under the goto label err:
These path are supposed to be mutually exclusive but they are not
actually. If the VHOST_USER_NEED_REPLY_MASK flag was passed and the
sending of the reply fails, both [1] and [2] are performed with the
same descriptor values. This can potentially cause subtle bugs if one
of the descriptor was recycled by some other thread in the meantime.
This code duplication complicates rollback for no real good benefit.
Do the closing in a unique place, under a new fdcleanup: goto label
at the end of the function.
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20210312092212.782255-3-groug@kaod.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
slave_read() checks EAGAIN when reading or writing to the socket
fails. This gives the impression that the slave channel is in
non-blocking mode, which is certainly not the case with the current
code base. And the rest of the code isn't actually ready to cope
with non-blocking I/O.
Just drop the checks everywhere in this function for the sake of
clarity.
Signed-off-by: Greg Kurz <groug@kaod.org>
Message-Id: <20210312092212.782255-2-groug@kaod.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
QEMU currently truncates the mmap_offset field when sending
VHOST_USER_ADD_MEM_REG and VHOST_USER_REM_MEM_REG messages. The struct
layout looks like this:
typedef struct VhostUserMemoryRegion {
uint64_t guest_phys_addr;
uint64_t memory_size;
uint64_t userspace_addr;
uint64_t mmap_offset;
} VhostUserMemoryRegion;
typedef struct VhostUserMemRegMsg {
uint32_t padding;
/* WARNING: there is a 32-bit hole here! */
VhostUserMemoryRegion region;
} VhostUserMemRegMsg;
The payload size is calculated as follows when sending the message in
hw/virtio/vhost-user.c:
msg->hdr.size = sizeof(msg->payload.mem_reg.padding) +
sizeof(VhostUserMemoryRegion);
This calculation produces an incorrect result of only 36 bytes.
sizeof(VhostUserMemRegMsg) is actually 40 bytes.
The consequence of this is that the final field, mmap_offset, is
truncated. This breaks x86_64 TCG guests on s390 hosts. Other guest/host
combinations may get lucky if either of the following holds:
1. The guest memory layout does not need mmap_offset != 0.
2. The host is little-endian and mmap_offset <= 0xffffffff so the
truncation has no effect.
Fix this by extending the existing 32-bit padding field to 64-bit. Now
the padding reflects the actual compiler padding. This can be verified
using pahole(1).
Also document the layout properly in the vhost-user specification. The
vhost-user spec did not document the exact layout. It would be
impossible to implement the spec without looking at the QEMU source
code.
Existing vhost-user frontends and device backends continue to work after
this fix has been applied. The only change in the wire protocol is that
QEMU now sets hdr.size to 40 instead of 36. If a vhost-user
implementation has a hardcoded size check for 36 bytes, then it will
fail with new QEMUs. Both QEMU and DPDK/SPDK don't check the exact
payload size, so they continue to work.
Fixes: f1aeb14b08 ("Transmit vhost-user memory regions individually")
Cc: Raphael Norwitz <raphael.norwitz@nutanix.com>
Cc: Cornelia Huck <cohuck@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20201109174355.1069147-1-stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Fixes: f1aeb14b08 ("Transmit vhost-user memory regions individually")
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
The VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS vhost-user protocol
feature introduced a shadow-table, used by the backend to dynamically
determine how a vdev's memory regions have changed since the last
vhost_user_set_mem_table() call. On hot-remove, a memmove() operation
is used to overwrite the removed shadow region descriptor(s). The size
parameter of this memmove was off by 1 such that if a VM with a backend
supporting the VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS filled it's
shadow-table (by performing the maximum number of supported hot-add
operatons) and attempted to remove the last region, Qemu would read an
out of bounds value and potentially crash.
This change fixes the memmove() bounds such that this erroneous read can
never happen.
Signed-off-by: Peter Turschmid <peter.turschm@nutanix.com>
Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <1594799958-31356-1-git-send-email-raphael.norwitz@nutanix.com>
Fixes: f1aeb14b08 ("Transmit vhost-user memory regions individually")
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Cc: qemu-stable@nongnu.org
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Prior to this change, the vhost_user_fill_msg_region function filled out
all elements of the VhostUserMemoryRegion struct except the mmap_offset.
This function is often called on uninitialized structs, which are then
copied into VHOST_USER_SET_MEM_TABLE and VHOST_USER_ADD/REM_MEM_REG
messages. In some cases, where the mmap_offset was not needed, it was
left uninitialized, causing QEMU to send the backend uninitialized data,
which Coverity flagged as a series of issues.
This change augments the vhost_user_fill_msg_region API, adding a
mmap_offset paramenter, forcing the caller to initialize mmap_offset.
Fixes: ece99091c2
Fixes: f1aeb14b08
Reported-by: Coverity (CIDs 1429802, 1429803 and 1429804)
Suggested-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <1592650156-25845-1-git-send-email-raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Historically, sending all memory regions to vhost-user backends in a
single message imposed a limitation on the number of times memory
could be hot-added to a VM with a vhost-user device. Now that backends
which support the VHOST_USER_PROTOCOL_F_CONFIGURE_SLOTS send memory
regions individually, we no longer need to impose this limitation on
devices which support this feature.
With this change, VMs with a vhost-user device which supports the
VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS can support a configurable
number of memory slots, up to the maximum allowed by the target
platform.
Existing backends which do not support
VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS are unaffected.
Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Peter Turschmid <peter.turschm@nutanix.com>
Suggested-by: Mike Cui <cui@nutanix.com>
Message-Id: <1588533678-23450-6-git-send-email-raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
With this change, when the VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS
protocol feature has been negotiated, Qemu no longer sends the backend
all the memory regions in a single message. Rather, when the memory
tables are set or updated, a series of VHOST_USER_ADD_MEM_REG and
VHOST_USER_REM_MEM_REG messages are sent to transmit the regions to map
and/or unmap instead of sending send all the regions in one fixed size
VHOST_USER_SET_MEM_TABLE message.
The vhost_user struct maintains a shadow state of the VM’s memory
regions. When the memory tables are modified, the
vhost_user_set_mem_table() function compares the new device memory state
to the shadow state and only sends regions which need to be unmapped or
mapped in. The regions which must be unmapped are sent first, followed
by the new regions to be mapped in. After all the messages have been
sent, the shadow state is set to the current virtual device state.
Existing backends which do not support
VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS are unaffected.
Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Swapnil Ingle <swapnil.ingle@nutanix.com>
Signed-off-by: Peter Turschmid <peter.turschm@nutanix.com>
Suggested-by: Mike Cui <cui@nutanix.com>
Message-Id: <1588533678-23450-5-git-send-email-raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Marc-André Lureau <marcandre.lureau@redhat.com>
This change introduces a new feature to the vhost-user protocol allowing
a backend device to specify the maximum number of ram slots it supports.
At this point, the value returned by the backend will be capped at the
maximum number of ram slots which can be supported by vhost-user, which
is currently set to 8 because of underlying protocol limitations.
The returned value will be stored inside the VhostUserState struct so
that on device reconnect we can verify that the ram slot limitation
has not decreased since the last time the device connected.
Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Signed-off-by: Peter Turschmid <peter.turschm@nutanix.com>
Message-Id: <1588533678-23450-4-git-send-email-raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
When setting the memory tables, qemu uses a memory region's userspace
address to look up the region's MemoryRegion struct. Among other things,
the MemoryRegion contains the region's offset and associated file
descriptor, all of which need to be sent to the backend.
With VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS, this logic will be
needed in multiple places, so before feature support is added it
should be moved to a helper function.
This helper is also used to simplify the vhost_user_can_merge()
function.
Signed-off-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
Message-Id: <1588533678-23450-3-git-send-email-raphael.norwitz@nutanix.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
