linux-toradex.git/include/uapi/linux/vhost.h, branch v6.16-rc6

vhost: fix VHOST_*_OWNER documentation

2025-04-14T13:51:31+00:00

VHOST_OWNER_SET and VHOST_OWNER_RESET are used in the documentation
instead of VHOST_SET_OWNER and VHOST_RESET_OWNER respectively.

To avoid confusion, let's use the right names in the documentation.
No change to the API, only the documentation is involved.

Signed-off-by: Stefano Garzarella 
Message-Id: <20250303085237.19990-1-sgarzare@redhat.com>
Signed-off-by: Michael S. Tsirkin

vhost-vdpa: change ioctl # for VDPA_GET_VRING_SIZE

2024-04-08T08:11:04+00:00

VDPA_GET_VRING_SIZE by mistake uses the already occupied
ioctl # 0x80 and we never noticed - it happens to work
because the direction and size are different, but confuses
tools such as perf which like to look at just the number,
and breaks the extra robustness of the ioctl numbering macros.

To fix, sort the entries and renumber the ioctl - not too late
since it wasn't in any released kernels yet.

Cc: Arnaldo Carvalho de Melo 
Reported-by: Namhyung Kim 
Fixes: 1496c47065f9 ("vhost-vdpa: uapi to support reporting per vq size")
Cc: "Zhu Lingshan" 
Signed-off-by: Michael S. Tsirkin 
Message-Id: <41c1c5489688abe5bfef9f7cf15584e3fb872ac5.1712092759.git.mst@redhat.com>
Reviewed-by: Eugenio Pérez 
Reviewed-by: Zhu Lingshan 
Reviewed-by: Stefano Garzarella 
Acked-by: Jason Wang

vhost-vdpa: uapi to support reporting per vq size

2024-03-19T06:45:49+00:00

The size of a virtqueue is a per vq configuration.
This commit introduce a new ioctl uAPI to support this flexibility.

Signed-off-by: Zhu Lingshan 
Message-Id: <20240202163905.8834-2-lingshan.zhu@intel.com>
Signed-off-by: Michael S. Tsirkin

vhost-vdpa: uAPI to get dedicated descriptor group id

2023-11-01T13:19:55+00:00

With _F_DESC_ASID backend feature, the device can now support the
VHOST_VDPA_GET_VRING_DESC_GROUP ioctl, and it may expose the descriptor
table (including avail and used ring) in a different group than the
buffers it contains. This new uAPI will fetch the group ID of the
descriptor table.

Signed-off-by: Si-Wei Liu 
Acked-by: Eugenio Pérez 
Acked-by: Jason Wang 
Message-Id: <20231018171456.1624030-6-dtatulea@nvidia.com>
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Si-Wei Liu 
Tested-by: Si-Wei Liu 
Tested-by: Lei Yang

vhost: Allow worker switching while work is queueing

2023-07-03T16:15:14+00:00

This patch drops the requirement that we can only switch workers if work
has not been queued by using RCU for the vq based queueing paths and a
mutex for the device wide flush.

We can also use this to support SIGKILL properly in the future where we
should exit almost immediately after getting that signal. With this
patch, when get_signal returns true, we can set the vq->worker to NULL
and do a synchronize_rcu to prevent new work from being queued to the
vhost_task that has been killed.

Signed-off-by: Mike Christie 
Message-Id: <20230626232307.97930-18-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin

vhost: allow userspace to create workers

2023-07-03T16:15:14+00:00

For vhost-scsi with 3 vqs or more and a workload that tries to use
them in parallel like:

fio --filename=/dev/sdb  --direct=1 --rw=randrw --bs=4k \
--ioengine=libaio --iodepth=128  --numjobs=3

the single vhost worker thread will become a bottlneck and we are stuck
at around 500K IOPs no matter how many jobs, virtqueues, and CPUs are
used.

To better utilize virtqueues and available CPUs, this patch allows
userspace to create workers and bind them to vqs. You can have N workers
per dev and also share N workers with M vqs on that dev.

This patch adds the interface related code and the next patch will hook
vhost-scsi into it. The patches do not try to hook net and vsock into
the interface because:

1. multiple workers don't seem to help vsock. The problem is that with
only 2 virtqueues we never fully use the existing worker when doing
bidirectional tests. This seems to match vhost-scsi where we don't see
the worker as a bottleneck until 3 virtqueues are used.

2. net already has a way to use multiple workers.

Signed-off-by: Mike Christie 
Message-Id: <20230626232307.97930-16-michael.christie@oracle.com>
Signed-off-by: Michael S. Tsirkin

vhost-vdpa: uAPI to resume the device

2023-02-21T00:26:56+00:00

This new ioctl adds support for resuming the device from userspace.

This is required when trying to restore the device in a functioning
state after it's been suspended. It is already possible to reset a
suspended device, but that means the device must be reconfigured and
all the IOMMU/IOTLB mappings must be recreated. This new operation
allows the device to be resumed without going through a full reset.

This is particularly useful when trying to perform offline migration of
a virtual machine (also known as snapshot/restore) as it allows the VMM
to resume the virtual machine back to a running state after the snapshot
is performed.

Acked-by: Jason Wang 
Signed-off-by: Sebastien Boeuf 
Message-Id: <73b75fb87d25cff59768b4955a81fe7ffe5b4770.1672742878.git.sebastien.boeuf@intel.com>
Signed-off-by: Michael S. Tsirkin 
Reviewed-by: Stefano Garzarella

vhost-vdpa: uAPI to suspend the device

2022-08-11T08:31:15+00:00

The ioctl adds support for suspending the device from userspace.

This is a must before getting virtqueue indexes (base) for live migration,
since the device could modify them after userland gets them. There are
individual ways to perform that action for some devices
(VHOST_NET_SET_BACKEND, VHOST_VSOCK_SET_RUNNING, ...) but there was no
way to perform it for any vhost device (and, in particular, vhost-vdpa).

After a successful return of the ioctl call the device must not process
more virtqueue descriptors. The device can answer to read or writes of
config fields as if it were not suspended. In particular, writing to
"queue_enable" with a value of 1 will not make the device start
processing buffers of the virtqueue.

Signed-off-by: Eugenio Pérez 
Message-Id: <20220810171512.2343333-4-eperezma@redhat.com>
Signed-off-by: Michael S. Tsirkin

vhost-vdpa: introduce uAPI to set group ASID

2022-05-31T16:44:31+00:00

Follows the vDPA support for associating ASID to a specific virtqueue
group. This patch adds a uAPI to support setting them from userspace.

Signed-off-by: Jason Wang 
Signed-off-by: Gautam Dawar 
Message-Id: <20220330180436.24644-15-gdawar@xilinx.com>
Signed-off-by: Michael S. Tsirkin

vhost-vdpa: uAPI to get virtqueue group id

2022-05-31T16:44:31+00:00

Follows the support for virtqueue group in vDPA. This patches
introduces uAPI to get the virtqueue group ID for a specific virtqueue
in vhost-vdpa.

Signed-off-by: Jason Wang 
Signed-off-by: Gautam Dawar 
Message-Id: <20220330180436.24644-14-gdawar@xilinx.com>
Signed-off-by: Michael S. Tsirkin